- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 03:56:47 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 43
TRIGGER_NUM: 401774186
GRB_RA: 61.917d {+04h 07m 40s} (J2000),
62.058d {+04h 08m 14s} (current),
61.401d {+04h 05m 36s} (1950)
GRB_DEC: -27.000d {-27d 00' 00"} (J2000),
-26.964d {-26d 57' 50"} (current),
-27.132d {-27d 07' 55"} (1950)
GRB_ERROR: 30.52 [deg radius, statistical plus systematic]
GRB_INTEN: 44 [cnts/sec]
DATA_SIGNIF: 4.70 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14183.29 SOD {03:56:23.29} UT
GRB_PHI: 65.00 [deg]
GRB_THETA: 45.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 3.59
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 56% GRB
2nd_MOST_LIKELY: 38% Generic SGR
DETECTORS: 1,1,1, 0,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN: 182.07d {+12h 08m 16s} -0.90d {-00d 53' 42"}
SUN_DIST: 116.02 [deg] Sun_angle= 8.0 [hr] (West of Sun)
MOON_POSTN: 69.19d {+04h 36m 45s} +19.22d {+19d 13' 30"}
MOON_DIST: 46.70 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 224.50,-46.61 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 52.19,-46.82 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 323.60,17.35 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 03:57:01 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 56
TRIGGER_NUM: 401774186
GRB_RA: 63.340d {+04h 13m 22s} (J2000),
63.474d {+04h 13m 54s} (current),
62.854d {+04h 11m 25s} (1950)
GRB_DEC: -31.790d {-31d 47' 23"} (J2000),
-31.756d {-31d 45' 20"} (current),
-31.916d {-31d 54' 57"} (1950)
GRB_ERROR: 10.81 [deg radius, statistical only]
DATA_SIGNIF: 5.00 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14183.29 SOD {03:56:23.29} UT
GRB_PHI: 58.00 [deg]
GRB_THETA: 45.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4143 (Gnd S/W Version number)
SUN_POSTN: 182.07d {+12h 08m 16s} -0.90d {-00d 53' 42"}
SUN_DIST: 113.49 [deg] Sun_angle= 7.9 [hr] (West of Sun)
MOON_POSTN: 69.19d {+04h 36m 45s} +19.23d {+19d 13' 30"}
MOON_DIST: 51.27 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 231.65,-46.19 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 51.96,-51.77 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:09:51 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 48
TRIGGER_NUM: 401774969
GRB_RA: 39.933d {+02h 39m 44s} (J2000),
40.059d {+02h 40m 14s} (current),
39.477d {+02h 37m 55s} (1950)
GRB_DEC: -45.950d {-45d 57' 00"} (J2000),
-45.891d {-45d 53' 28"} (current),
-46.164d {-46d 09' 50"} (1950)
GRB_ERROR: 14.18 [deg radius, statistical plus systematic]
GRB_INTEN: 73 [cnts/sec]
DATA_SIGNIF: 5.10 [sigma]
INTEG_TIME: 2.048 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14966.73 SOD {04:09:26.73} UT
GRB_PHI: 252.00 [deg]
GRB_THETA: 25.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO: 1.16
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 98% GRB
2nd_MOST_LIKELY: 1% Generic SGR
DETECTORS: 0,0,0, 0,0,0, 1,1,0, 0,0,0, 0,0,
SUN_POSTN: 182.07d {+12h 08m 18s} -0.90d {-00d 53' 55"}
SUN_DIST: 122.50 [deg] Sun_angle= 9.5 [hr] (West of Sun)
MOON_POSTN: 69.30d {+04h 37m 13s} +19.23d {+19d 13' 56"}
MOON_DIST: 70.31 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 261.41,-61.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 13.05,-56.82 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 6.13,-2.33 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:10:01 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 58
TRIGGER_NUM: 401774969
GRB_RA: 40.067d {+02h 40m 16s} (J2000),
40.209d {+02h 40m 50s} (current),
39.548d {+02h 38m 11s} (1950)
GRB_DEC: -34.200d {-34d 12' 00"} (J2000),
-34.142d {-34d 08' 29"} (current),
-34.414d {-34d 24' 49"} (1950)
GRB_ERROR: 9.35 [deg radius, statistical plus systematic]
GRB_INTEN: 154 [cnts/sec]
DATA_SIGNIF: 17.40 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14966.73 SOD {04:09:26.73} UT
GRB_PHI: 225.00 [deg]
GRB_THETA: 20.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.73
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 97% GRB
2nd_MOST_LIKELY: 2% Generic Transient
DETECTORS: 0,0,0, 0,0,0, 1,1,0, 0,0,0, 0,0,
SUN_POSTN: 182.07d {+12h 08m 18s} -0.90d {-00d 53' 55"}
SUN_DIST: 129.95 [deg] Sun_angle= 9.5 [hr] (West of Sun)
MOON_POSTN: 69.30d {+04h 37m 13s} +19.23d {+19d 13' 56"}
MOON_DIST: 60.13 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 236.48,-65.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 22.71,-46.67 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 6.13,-2.33 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:10:04 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 57
TRIGGER_NUM: 401774969
GRB_RA: 37.210d {+02h 28m 50s} (J2000),
37.362d {+02h 29m 27s} (current),
36.656d {+02h 26m 37s} (1950)
GRB_DEC: -27.300d {-27d 18' 00"} (J2000),
-27.239d {-27d 14' 20"} (current),
-27.523d {-27d 31' 20"} (1950)
GRB_ERROR: 9.69 [deg radius, statistical only]
DATA_SIGNIF: 8.70 [sigma]
DATA_INTERVAL: 2.048 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14966.73 SOD {04:09:26.73} UT
GRB_PHI: 204.00 [deg]
GRB_THETA: 21.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4143 (Gnd S/W Version number)
SUN_POSTN: 182.07d {+12h 08m 18s} -0.90d {-00d 53' 55"}
SUN_DIST: 135.93 [deg] Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN: 69.31d {+04h 37m 13s} +19.23d {+19d 13' 56"}
MOON_DIST: 55.83 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 219.01,-68.38 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 23.70,-39.39 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: In the LAT Field-of-view.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:10:06 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 69
TRIGGER_NUM: 401774969
GRB_RA: 46.350d {+03h 05m 24s} (J2000),
46.493d {+03h 05m 58s} (current),
45.829d {+03h 03m 19s} (1950)
GRB_DEC: -30.717d {-30d 43' 00"} (J2000),
-30.664d {-30d 39' 49"} (current),
-30.910d {-30d 54' 34"} (1950)
GRB_ERROR: 6.77 [deg radius, statistical plus systematic]
GRB_INTEN: 227 [cnts/sec]
DATA_SIGNIF: 24.50 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14966.73 SOD {04:09:26.73} UT
GRB_PHI: 220.00 [deg]
GRB_THETA: 15.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 0.84
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 98% GRB
2nd_MOST_LIKELY: 1% Generic Transient
DETECTORS: 0,0,0, 0,0,0, 1,1,0, 0,0,0, 0,0,
SUN_POSTN: 182.07d {+12h 08m 18s} -0.90d {-00d 53' 55"}
SUN_DIST: 127.32 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 69.31d {+04h 37m 13s} +19.23d {+19d 13' 56"}
MOON_DIST: 54.50 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 228.00,-60.58 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 31.77,-45.73 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 6.13,-2.33 [deg].
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:10:08 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 68
TRIGGER_NUM: 401774969
GRB_RA: 43.260d {+02h 53m 02s} (J2000),
43.404d {+02h 53m 37s} (current),
42.736d {+02h 50m 57s} (1950)
GRB_DEC: -31.370d {-31d 22' 11"} (J2000),
-31.314d {-31d 18' 51"} (current),
-31.574d {-31d 34' 24"} (1950)
GRB_ERROR: 4.85 [deg radius, statistical only]
DATA_SIGNIF: 22.80 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14966.73 SOD {04:09:26.73} UT
GRB_PHI: 219.00 [deg]
GRB_THETA: 17.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4143 (Gnd S/W Version number)
SUN_POSTN: 182.07d {+12h 08m 18s} -0.90d {-00d 53' 55"}
SUN_DIST: 129.29 [deg] Sun_angle= 9.2 [hr] (West of Sun)
MOON_POSTN: 69.31d {+04h 37m 13s} +19.23d {+19d 13' 56"}
MOON_DIST: 56.33 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 229.37,-63.22 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 27.94,-45.26 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: In the LAT Field-of-view.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:10:16 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 71
TRIGGER_NUM: 401774969
GRB_RA: 45.480d {+03h 01m 55s} (J2000),
45.624d {+03h 02m 30s} (current),
44.955d {+02h 59m 49s} (1950)
GRB_DEC: -30.290d {-30d 17' 23"} (J2000),
-30.236d {-30d 14' 10"} (current),
-30.486d {-30d 29' 09"} (1950)
GRB_ERROR: 1.74 [deg radius, statistical only]
DATA_SIGNIF: 27.20 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 14966.73 SOD {04:09:26.73} UT
GRB_PHI: 218.00 [deg]
GRB_THETA: 16.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4143 (Gnd S/W Version number)
SUN_POSTN: 182.07d {+12h 08m 18s} -0.90d {-00d 53' 55"}
SUN_DIST: 128.18 [deg] Sun_angle= 9.1 [hr] (West of Sun)
MOON_POSTN: 69.31d {+04h 37m 14s} +19.23d {+19d 13' 56"}
MOON_DIST: 54.47 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 227.07,-61.31 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 31.03,-45.04 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: In the LAT Field-of-view.
COMMENTS: This Notice was ground-generated -- not flight-generated.
- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:12:41 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 571830, Seg_Num: 0
GRB_RA: 41.183d {+02h 44m 44s} (J2000),
41.335d {+02h 45m 20s} (current),
40.633d {+02h 42m 32s} (1950)
GRB_DEC: -26.134d {-26d 08' 03"} (J2000),
-26.077d {-26d 04' 36"} (current),
-26.345d {-26d 20' 40"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 0 [cnts] Image_Peak=5621 [image_cnts]
TRIGGER_DUR: 64.000 [sec]
TRIGGER_INDEX: 20000 E_range: 15-50 keV
BKG_INTEN: 0 [cnts]
BKG_TIME: 0.00 SOD {00:00:00.00} UT
BKG_DUR: 0 [sec]
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 15084.92 SOD {04:11:24.92} UT
GRB_PHI: 123.18 [deg]
GRB_THETA: 40.79 [deg]
SOLN_STATUS: 0x13
RATE_SIGNIF: 0.00 [sigma]
IMAGE_SIGNIF: 23.15 [sigma]
MERIT_PARAMS: +1 +0 +0 +6 +1 +8 +0 +0 +68 +0
SUN_POSTN: 182.08d {+12h 08m 18s} -0.90d {-00d 53' 58"}
SUN_DIST: 133.51 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.33d {+04h 37m 19s} +19.23d {+19d 14' 01"}
MOON_DIST: 52.84 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.18,-64.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 28.52,-39.74 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Coordinates.
COMMENTS: This is an image trigger. (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 340.00,9.06 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:14:30 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 571830, Seg_Num: 0
GRB_RA: 41.1766d {+02h 44m 42.38s} (J2000),
41.3278d {+02h 45m 18.67s} (current),
40.6260d {+02h 42m 30.24s} (1950)
GRB_DEC: -26.1544d {-26d 09' 15.8"} (J2000),
-26.0969d {-26d 05' 48.9"} (current),
-26.3648d {-26d 21' 53.3"} (1950)
GRB_ERROR: 5.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 5.86e-08 [erg/cm2/sec]
GRB_SIGNIF: 8.48 [sigma]
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15232.31 SOD {04:13:52.31} UT, 147.4 [sec] since BAT Trigger Time
TAM[0-3]: 327.66 237.20 261.69 243.49
AMPLIFIER: 2
WAVEFORM: 134
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 00"}
SUN_DIST: 133.51 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.34d {+04h 37m 23s} +19.23d {+19d 14' 05"}
MOON_DIST: 52.87 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.23,-64.72 [deg] galactic lon,lat of the burst
ECL_COORDS: 28.50,-39.75 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: The XRT position is 1.25 arcmin from the BAT position.
COMMENTS: The object found at this position is either a very bright burst or a cosmic ray hit.
COMMENTS: Examine the XRT Image to differentiate (CRs are much more compact); see examples at:
COMMENTS: http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:14:40 UT
NOTICE_TYPE: Swift-XRT Image
TRIGGER_NUM: 571830, Seg_Num: 0
GRB_RA: 41.1766d {+02h 44m 42.3s} (J2000),
41.3278d {+02h 45m 18.6s} (current),
40.6260d {+02h 42m 30.2s} (1950)
GRB_DEC: -26.1544d {-26d 09' 15.8"} (J2000),
-26.0969d {-26d 05' 48.9"} (current),
-26.3648d {-26d 21' 53.3"} (1950)
GRB_ERROR: 5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 72 [cnts]
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15232.31 SOD {04:13:52.31} UT, 147.4 [sec] since BAT Trigger Time
CENTROID_X: 327.67, raw= 328 [pixels]
CENTROID_Y: 274.10, raw= 274 [pixels]
ROLL: 119.41 [deg]
GAIN: 2
MODE: 2, Short Image mode
WAVEFORM: 134
EXPO_TIME: 0.10 [sec]
GRB_POS_XRT_Y: -56.32
GRB_POS_XRT_Z: 56.51
IMAGE_URL: sw00571830000msxps_rw.img
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 00"}
SUN_DIST: 133.51 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.35d {+04h 37m 23s} +19.23d {+19d 14' 05"}
MOON_DIST: 52.87 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.23,-64.72 [deg] galactic lon,lat of the burst
ECL_COORDS: 28.50,-39.75 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Image.
COMMENTS: The object found at this position is either a very bright burst or a cosmic ray hit.
COMMENTS: Examine the XRT Image to differentiate (CRs are much more compact); see examples at:
COMMENTS: http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:14:57 UT
NOTICE_TYPE: Swift-XRT Processed Image
TRIGGER_NUM: 571830, Seg_Num: 0
GRB_RA: 41.1766d {+02h 44m 42.3s} (J2000),
41.3278d {+02h 45m 18.6s} (current),
40.6260d {+02h 42m 30.2s} (1950)
GRB_DEC: -26.1544d {-26d 09' 15.8"} (J2000),
-26.0969d {-26d 05' 48.9"} (current),
-26.3648d {-26d 21' 53.3"} (1950)
GRB_ERROR: 5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 72 [cnts]
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15232.31 SOD {04:13:52.31} UT, 147.4 [sec] since BAT Trigger Time
CENTROID_X: 327.67, raw= 328 [pixels]
CENTROID_Y: 274.10, raw= 274 [pixels]
ROLL: 119.41 [deg]
GAIN: 2
MODE: 2, Short Image mode
WAVEFORM: 134
EXPO_TIME: 0.10 [sec]
GRB_POS_XRT_Y: -56.32
GRB_POS_XRT_Z: 56.51
IMAGE_URL: sw00571830000msxps_rw.img
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 00"}
SUN_DIST: 133.51 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.35d {+04h 37m 24s} +19.23d {+19d 14' 06"}
MOON_DIST: 52.87 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.23,-64.72 [deg] galactic lon,lat of the burst
ECL_COORDS: 28.50,-39.75 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Processed Image.
COMMENTS: The object found at this position is either a very bright burst or a cosmic ray hit.
COMMENTS: Examine the XRT Image to differentiate (CRs are much more compact); see examples at:
COMMENTS: http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:15:29 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 571830, Seg_Num: 0
GRB_RA: 41.183d {+02h 44m 44s} (J2000),
41.335d {+02h 45m 20s} (current),
40.633d {+02h 42m 32s} (1950)
GRB_DEC: -26.134d {-26d 08' 03"} (J2000),
-26.077d {-26d 04' 36"} (current),
-26.345d {-26d 20' 40"} (1950)
GRB_DATE: 16560 TJD; 268 DOY; 13/09/25
GRB_TIME: 15084.92 SOD {04:11:24.92} UT
TRIGGER_INDEX: 20000
GRB_PHI: 123.18 [deg]
GRB_THETA: 40.79 [deg]
DELTA_TIME: 0.00 [sec]
TRIGGER_DUR: 64.000 [sec]
SOLN_STATUS: 0x13
RATE_SIGNIF: 0.00 [sigma]
IMAGE_SIGNIF: 23.15 [sigma]
LC_URL: sw00571830000msb.lc
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 00"}
SUN_DIST: 133.51 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.35d {+04h 37m 25s} +19.24d {+19d 14' 07"}
MOON_DIST: 52.85 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.18,-64.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 28.52,-39.74 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS: The next comments were copied from the BAT_POS Notice:
COMMENTS: This is an image trigger.
COMMENTS: A point_source was found.
COMMENTS: This does not match any source in the on-board catalog.
COMMENTS: This does not match any source in the ground catalog.
COMMENTS: This is a GRB.
COMMENTS: This trigger occurred at longitude,latitude = 340.00,9.06 [deg].
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:17:07 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.202d {+02h 44m 48s} (J2000)
POINT_DEC: -26.145d {-26d 08' 41"} (J2000)
POINT_ROLL: 119.404d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15240.96 SOD {04:14:00.96} UT, 156.0 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 1.793
N_STARS: 190
X_OFFSET: 336 [pixels]
Y_OFFSET: 600 [pixels]
X_MAX: 1295 [pixels]
Y_MAX: 1559 [pixels]
DET_THRESH: 11
PHOTO_THRESH: 6
SL_URL: sw00571830000msufc0156.fits
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 02"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.37d {+04h 37m 28s} +19.24d {+19d 14' 10"}
MOON_DIST: 52.86 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.21,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.75 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:17:50 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.202d {+02h 44m 48s} (J2000)
POINT_DEC: -26.145d {-26d 08' 41"} (J2000)
POINT_ROLL: 119.404d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15240.96 SOD {04:14:00.96} UT, 156.0 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 1.793
N_STARS: 190
X_OFFSET: 336 [pixels]
Y_OFFSET: 600 [pixels]
X_MAX: 1295 [pixels]
Y_MAX: 1559 [pixels]
DET_THRESH: 11
PHOTO_THRESH: 6
SL_URL: sw00571830000msufc0156.fits
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 03"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.37d {+04h 37m 30s} +19.24d {+19d 14' 11"}
MOON_DIST: 52.87 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.21,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.75 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:18:22 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.202d {+02h 44m 48s} (J2000)
POINT_DEC: -26.145d {-26d 08' 41"} (J2000)
ROLL: 119.404d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15240.96 SOD {04:14:00.96} UT, 156.0 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 401775252
X_OFFSET: 751 [pixels]
Y_OFFSET: 1029 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 911
Y_GRB_POS: 1189
BINNING_INDEX: 1
IM_URL: sw00571830000msuni0168.fits
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 03"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.38d {+04h 37m 31s} +19.24d {+19d 14' 12"}
MOON_DIST: 52.87 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.21,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.75 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:18:40 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.202d {+02h 44m 48s} (J2000)
POINT_DEC: -26.145d {-26d 08' 41"} (J2000)
ROLL: 119.404d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15240.96 SOD {04:14:00.96} UT, 156.0 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 401775252
X_OFFSET: 751 [pixels]
Y_OFFSET: 1029 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 911
Y_GRB_POS: 1189
BINNING_INDEX: 1
IM_URL: sw00571830000msuni0168.fits
SUN_POSTN: 182.08d {+12h 08m 19s} -0.90d {-00d 54' 03"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.38d {+04h 37m 32s} +19.24d {+19d 14' 13"}
MOON_DIST: 52.87 [deg]
MOON_ILLUM: 69 [%]
GAL_COORDS: 217.21,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.75 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:23:34 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.149d {-26d 08' 54"} (J2000)
POINT_ROLL: 119.406d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15399.76 SOD {04:16:39.76} UT, 314.8 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 0.564
N_STARS: 190
X_OFFSET: 431 [pixels]
Y_OFFSET: 709 [pixels]
X_MAX: 1390 [pixels]
Y_MAX: 1668 [pixels]
DET_THRESH: 7
PHOTO_THRESH: 3
SL_URL: sw00571830000msufc0314.fits
SUN_POSTN: 182.08d {+12h 08m 20s} -0.90d {-00d 54' 08"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.43d {+04h 37m 42s} +19.24d {+19d 14' 22"}
MOON_DIST: 52.90 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:23:46 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.149d {-26d 08' 54"} (J2000)
POINT_ROLL: 119.406d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15399.76 SOD {04:16:39.76} UT, 314.8 [sec] since BAT Trigger Time
FILTER: 7, U
BKG_MEAN: 0.564
N_STARS: 190
X_OFFSET: 431 [pixels]
Y_OFFSET: 709 [pixels]
X_MAX: 1390 [pixels]
Y_MAX: 1668 [pixels]
DET_THRESH: 7
PHOTO_THRESH: 3
SL_URL: sw00571830000msufc0314.fits
SUN_POSTN: 182.08d {+12h 08m 20s} -0.90d {-00d 54' 08"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.43d {+04h 37m 42s} +19.24d {+19d 14' 23"}
MOON_DIST: 52.90 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:24:25 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.149d {-26d 08' 54"} (J2000)
ROLL: 119.406d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15399.76 SOD {04:16:39.76} UT, 314.8 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 401775410
X_OFFSET: 751 [pixels]
Y_OFFSET: 1029 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 911
Y_GRB_POS: 1189
BINNING_INDEX: 1
IM_URL: sw00571830000msuni0326.fits
SUN_POSTN: 182.08d {+12h 08m 20s} -0.90d {-00d 54' 09"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.43d {+04h 37m 44s} +19.24d {+19d 14' 24"}
MOON_DIST: 52.90 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:24:40 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.149d {-26d 08' 54"} (J2000)
ROLL: 119.406d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15399.76 SOD {04:16:39.76} UT, 314.8 [sec] since BAT Trigger Time
FILTER: 7, U
EXPOSURE_ID: 401775410
X_OFFSET: 751 [pixels]
Y_OFFSET: 1029 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 911
Y_GRB_POS: 1189
BINNING_INDEX: 1
IM_URL: sw00571830000msuni0326.fits
SUN_POSTN: 182.08d {+12h 08m 20s} -0.90d {-00d 54' 09"}
SUN_DIST: 133.49 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.43d {+04h 37m 44s} +19.24d {+19d 14' 25"}
MOON_DIST: 52.90 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: If you have elected to receive attachments:
COMMENTS: The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.
- GCN Circular #15246
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), M. H. Siegel (PSU) and T. N. Ukwatta (MSU)
report on behalf of the Swift Team:
At 04:11:24 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130925A (trigger=571830). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 41.183, -26.134 which is
RA(J2000) = 02h 44m 44s
Dec(J2000) = -26d 08' 03"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed that the burst
was active during the pre-planned slew before the nominal trigger
with an additional peak extending at least to T+170. The peak count
rate was ~2700 counts/sec (15-350 keV), at ~110 sec after the trigger.
The XRT began observing the field at 04:13:52.3 UT, 147.4 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 41.1766, -26.1544 which is equivalent to:
RA(J2000) = +02h 44m 42.38s
Dec(J2000) = -26d 09' 15.8"
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This
location is 76 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 156 seconds after the BAT trigger. No credible
afterglow candidate has been found in the initial data products. The
2.7'x2.7' covers 100% of the XRT error circle. The typical 3-sigma
upper limit has been about 19.6 mag. Results from the list of sources
generated on-board are not available at this time. No correction has
been made for the expected extinction corresponding to E(B-V) of
0.02.
Burst Advocate for this burst is A. Y. Lien (yarleen AT gmail.com).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:29:10 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.148d {-26d 08' 54"} (J2000)
POINT_ROLL: 119.407d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15954.59 SOD {04:25:54.59} UT, 869.7 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 2.102
N_STARS: 190
X_OFFSET: 191 [pixels]
Y_OFFSET: 469 [pixels]
X_MAX: 1630 [pixels]
Y_MAX: 1908 [pixels]
DET_THRESH: 12
PHOTO_THRESH: 6
SL_URL: sw00571830000msufc0869.fits
SUN_POSTN: 182.09d {+12h 08m 21s} -0.90d {-00d 54' 14"}
SUN_DIST: 133.50 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.47d {+04h 37m 54s} +19.24d {+19d 14' 33"}
MOON_DIST: 52.92 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:29:37 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.148d {-26d 08' 54"} (J2000)
POINT_ROLL: 119.407d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15954.59 SOD {04:25:54.59} UT, 869.7 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 2.102
N_STARS: 190
X_OFFSET: 191 [pixels]
Y_OFFSET: 469 [pixels]
X_MAX: 1630 [pixels]
Y_MAX: 1908 [pixels]
DET_THRESH: 12
PHOTO_THRESH: 6
SL_URL: sw00571830000msufc0869.fits
SUN_POSTN: 182.09d {+12h 08m 21s} -0.90d {-00d 54' 14"}
SUN_DIST: 133.50 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.48d {+04h 37m 55s} +19.24d {+19d 14' 34"}
MOON_DIST: 52.93 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Source List.
COMMENTS: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:30:35 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.148d {-26d 08' 54"} (J2000)
ROLL: 119.407d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15954.59 SOD {04:25:54.59} UT, 869.7 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 401775965
X_OFFSET: 750 [pixels]
Y_OFFSET: 1028 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 910
Y_GRB_POS: 1188
BINNING_INDEX: 1
IM_URL: sw00571830000msuni0881.fits
SUN_POSTN: 182.09d {+12h 08m 21s} -0.90d {-00d 54' 15"}
SUN_DIST: 133.50 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.49d {+04h 37m 57s} +19.24d {+19d 14' 36"}
MOON_DIST: 52.93 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:30:45 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 571830, Seg_Num: 0
POINT_RA: 41.200d {+02h 44m 48s} (J2000)
POINT_DEC: -26.148d {-26d 08' 54"} (J2000)
ROLL: 119.407d
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 15954.59 SOD {04:25:54.59} UT, 869.7 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 401775965
X_OFFSET: 750 [pixels]
Y_OFFSET: 1028 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 910
Y_GRB_POS: 1188
BINNING_INDEX: 1
IM_URL: sw00571830000msuni0881.fits
SUN_POSTN: 182.09d {+12h 08m 21s} -0.90d {-00d 54' 15"}
SUN_DIST: 133.50 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.49d {+04h 37m 57s} +19.24d {+19d 14' 36"}
MOON_DIST: 52.93 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.70 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 28.53,-39.76 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the Window Position in the Mode Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: All 4 attachments are included.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Wed 25 Sep 13 04:46:03 UT
NOTICE_TYPE: Swift-XRT Position UPDATE
TRIGGER_NUM: 571830, Seg_Num: 0
GRB_RA: 41.1769d {+02h 44m 42.45s} (J2000),
41.3281d {+02h 45m 18.75s} (current),
40.6263d {+02h 42m 30.31s} (1950)
GRB_DEC: -26.1525d {-26d 09' 08.9"} (J2000),
-26.0950d {-26d 05' 42.0"} (current),
-26.3629d {-26d 21' 46.5"} (1950)
GRB_ERROR: 3.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 1.00e-10 [erg/cm2/sec]
GRB_SIGNIF: 10.00 [sigma]
IMG_START_DATE: 16560 TJD; 268 DOY; 13/09/25
IMG_START_TIME: 16356.00 SOD {04:32:36.00} UT, 1271.1 [sec] since BAT Trigger Time
TAM[0-3]: 100.00 100.00 100.00 100.00
AMPLIFIER: 1
WAVEFORM: 31
SUN_POSTN: 182.10d {+12h 08m 23s} -0.91d {-00d 54' 30"}
SUN_DIST: 133.52 [deg] Sun_angle= 9.4 [hr] (West of Sun)
MOON_POSTN: 69.62d {+04h 38m 30s} +19.25d {+19d 15' 06"}
MOON_DIST: 53.02 [deg]
MOON_ILLUM: 68 [%]
GAL_COORDS: 217.22,-64.72 [deg] galactic lon,lat of the burst
ECL_COORDS: 28.50,-39.75 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.
COMMENTS: TAM values, flux and significance fields are not valid.
COMMENTS: This position was automatically generated on the ground using
COMMENTS: Photon Counting data telemetered via TDRSS (SPER data).
COMMENTS: See http://www.swift.ac.uk/sper/docs.php for details.
COMMENTS: The probability that this is a serendipitous source in the
COMMENTS: SPER window is 0.11% < P(seren) < 0.58%.
- GCN Circular #15247
V. Sudilovsky (MPE Garching), D.A. Kann, and J. Greiner
(all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 130925A (Lien et al., GCN #15246)
simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla
Observatory (Chile).
The first epoch observation started at 04:18:52 UT on 25 Sept 2013,
7 minutes after the GRB trigger. They were performed at an average
seeing of 0.7" and at an average airmass of 1.3. We do not find any
sources within the revised 3".6 Swift XRT error circle. However, we do
find an uncataloged red source 2" east of the error circle at position:
RA (J2000.0) = 02:44:42.96 = 41.1790
Dec. (J2000.0) = -26:09:11.16 = -26.1531
with an uncertainty of 0.3" in each coordinate.
Based on a total exposure of 4.4 minutes in g'r'i'z' and 4 minutes in
JHK, we estimate preliminary magnitudes (all in AB) of
g' > 21.5 mag,
r' > 22 mag,
i' = 21.8 +- 0.1 mag,
z' = 21.3 +- 0.1 mag,
J = 19.6 +- 0.1 mag,
H = 18.6 +- 0.1 mag, and
K = 18.0 +- 0.1 mag.
The source is seen to be brightening in the first images before
fading strongly. We suggest this source to be the afterglow of GRB
130925A.
Given magnitudes are calibrated against GROND zeropoints as well as
2MASS field stars and are not corrected for the expected Galactic
foreground extinction corresponding to a reddening of E_(B-V) =3D 0.02
mag in the direction of the burst (Schlegel et al. 1998).
- GCN Circular #15248
K. Suzuki, H. Sakakibara, H. Negoro (Nihon U.),
S. Nakahira, H. Tomida, S. Ueno, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA),
T. Mihara, M. Sugizaki, M. Morii, M. Serino, T. Yamamoto, J. Sugimoto,
T. Takagi, M. Matsuoka (RIKEN),
N. Kawai, R. Usui, K. Ishikawa, T. Yoshii (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Nakano (AGU),
H. Tsunemi, M. Sasaki (Osaka U.),
M. Nakajima, K. Fukushima, T. Onodera (Nihon U.),
Y. Ueda, M. Shidatsu, T. Kawamuro (Kyoto U.),
Y. Tsuboi, M. Higa (Chuo U.),
M. Yamauchi, K. Yoshidome, Y. Ogawa, H. Yamada (Miyazaki U.),
K. Yamaoka (Nagoya U.)
report on behalf of the MAXI team:
The MAXI/GSC Nova alert system triggered a bright uncatalogued X-ray transient source at
UT 2013-09-25T05:13:41.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(41.38 deg, -25.91 deg) = (02 45 32, -25 54 54)(J2000)
with a 90% C.L. statistical error of 0.2 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius).
The position is consistent with that of GRB 130925A (Lien et al. GCN #12526),
and apart from GRB 130925A by 0.30 deg.
This detection is, however, about 1 hour after the Swift detection.
The 2-20 keV flux was 290 (-51/+53) mCrab. An absorbed power-law fit to the burst spectrum
gives a photon index 1.62 +/- 0.27.
There was no significant excess flux in the previous transit at 03:41 UT
and in the next transit at 06:47 UT with an upper limit of 20 mCrab for each.
- GCN Circular #15249
P. M. Vreeswijk (Weizmann), D. Malesani, J. P. U. Fynbo (DARK/NBI),
A. De Cia (Weizmann) and C. Ledoux (ESO) report:
GRB 130925A (Lien et al., GCN 15246; Suzuki et al., GCN 15248) was
observed with UVES at the ESO-VLT, in Rapid Response Mode, starting at
around 5 UT (50 minutes after the Swift trigger). A series of spectra
were taken of the brightest object near the XRT error circle. We
caution that the small field of view of the UVES acquisition camera
and the lack of nearby bright stars does not allow us to identify this
object unambiguously as the optical counterpart discovered by
Sudilovsky et al. (GCN 15247).
Preliminary analysis of the automatically reduced spectra reveals the
presence of a very faint continuum in the red part and a pair of
emission lines at 8845 A and 8873 A. These lines can be identified
with Halpha and [NII] 6585 at a redshift of z=0.347.
We are grateful for the excellent support at Paranal provided by
Jonathan Smoker and Patricia Guajardo, and we thank D. A. Kann and the
GROND team for showing us a finding chart of the afterglow field.
- GCN Circular #15250
V. Sudilovsky, D.A. Kann, P. Schady (all MPE Garching), S. Klose (TLS
Tautenburg), J. Greiner (MPE Garching), and T. Kruehler (ESO) report:
We observed the optical/NIR afterglow (Sudilovsky et al., GCN 15247) of
GRB 130925A (Swift trigger 571830, Lien et al., GCN 15246) using ESO/VLT
UT2 equipped with the X-shooter spectrograph.
Observations started at 07:42 UT on 2013-09-25, about 3.5 hr after the
Swift trigger. A total exposure of 1.6 hr was obtained, covering the
spectral range from 3000 to 20500 AA.
In the spectrum we detect emission lines, which we interpret as being due
to [O II](3726,3729), H_beta, [O III](4959), [O III](5007) and H_alpha at
a common redshift of z = 0.35, in agreement with Vreeswijk et al. (GCN
15249).
We thank the Paranal staff for excellent support, in particular Linda
Schmidtobreick, Jonathan Smoker and Patricia.
- GCN Circular #15251
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 614 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 130925A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 41.17877, -26.15300 which is equivalent
to:
RA (J2000): 02h 44m 42.91s
Dec (J2000): -26d 09' 10.8"
with an uncertainty of 1.6 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
- GCN Circular #15252
Klotz A. (IRAP-CNRS-OMP), Gendre B. (IRAP-CNRS-OMP),
Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA),
Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 130925A detected by SWIFT
(trigger 571830) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.
The observations started 88.1s after the GRB trigger
(13.0s after the notice). The elevation of the field increased from
50 degrees above horizon and weather conditions
were good.
We do not detect the afterglow discovered by Sudilovsky
et al. (GCNC 15247, GCNC 15250) and confirmed by Vreeswijk
et al. (GCNC 15249). However, the observations of TAROT
give upper optical limits of the early afterglow.
The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39):
t0+88.1s to t0+148.1s : Rlim = 17.5
We co-added a series of exposures with diurnal drift:
t0+477s to t0+1081s : Rlim = 19.2
Magnitudes were estimated with the nearby NOMAD1 stars
and are not corrected for galactic dust extinction.
- GCN Circular #15253
D. N. Burrows (PSU), D. Malesani (DARK/NBI), A. Y. Lien (NASA/GSFC/ORAU),
S. B. Cenko (NASA/GSFC), and N. Gehrels (NASA/GSFC) report:
At 04:11:24 UT on 25 September 2013, the Swift BAT triggered on an object
denoted as GRB 130925A on the assumption that it is a gamma-ray burst
(Lien et al., GCN 15246). Here we note that this source presents several
unusual features that are atypical of GRBs.
The initial XRT observations show extremely rapid and dramatic flaring
over the first 10^4 s, far in excess of what we typically see in GRBs.
The high X-ray flux at these relatively late times is likely what resulted
in the detection of this source by MAXI ~ 1 hour after the GRB (Suzuki
et al., GCN 15248). The Swift/XRT light curve is available at the
following URL:
http://www.swift.ac.uk/xrt_curves/00571830/
We note that this behavior is at first glance similar to the highly
variable soft X-ray light curve observed from Swift J1644+57 (GRB
110328A), which has been interpreted as a newly formed relativistic jet
resulting from the tidal disruption of a star by a super-massive black
hole (Burrows et al. 2011; Levan et al. 2011; Zauderer et al. 2011; Bloom
et al. 2011). Like Swift J1644+57, GRB 130925A is a BAT image trigger,
is associated with highly absorbed optical/NIR transient emission
(Sudilovsky et al., GCN 15247), and lies at a relatively low redshift
(z = 0.347; Vreeswijk et al., GCN 15249; Sudilovsky et al., GCN 15250).
We encourage observations at all wavelengths to help determine the nature
of this interesting source.
- GCN Circular #15254
P.A. Evans, C. Pagani, K.L. Page, A.P. Beardmore, R.L.C. Starling (U.
Leicester) and A. Y. Lien (NASA/GSFC/ORAU) report on behalf of the
Swift-XRT team:
We have analysed 4.7 ks of XRT data for GRB 130925A (Lien et al. GCN
Circ. 15246), from 151 s to 12.0 ks after the BAT trigger. The data
comprise 3.2 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Evans et al. (GCN. Circ 15251).
The light curve behaviour is dominated by sharp, bright flares. The
initial decay follows a power-law with an index of 2.70 (+/- 0.03) and
then breaks at T0+464 (+9,-6) to a virtually flat segment, with a
formal decay index of 0.16 (+0.11, -0.17). At this point the XRT count
rate is 47 ct/sec (approx 2.1e-9 erg cm^-2 s^-1, 0.3-10 keV). Then at
T0+750 a flare begins, which peaks at T0+1000 s at a count rate of ~100
ct/sec. This flare fades steeply to ~8 ct/sec at T0+1240 s at which
point a second, steep and bright flare begins. This peaks at T0+1380 s
at a count rate of ~150 ct/sec. The Swift observations were interrupted
at T0+1503 s as the GRB entered Earth-eclipse; the count-rate by this
time had fallen to ~50 ct/sec.
The MAXI detection (Suzuki et al., GCN Circ. 15248) took place while
the GRB was thus unobservable by Swift and corresponds to an XRT count
rate of ~80 ct/sec.
Swift began observing the GRB again at T0+4.75 ks; the count rate was
~8 ct/sec, but rapidly rising due to another flare which peaked 200 s
later at ~130 ct/sec, and then faded to ~3 ct/sec by T0+6.1 ks. Another
flare began shortly after, at T0+6.6 ks and peaked at T0+7.1 ks at 150
ct/sec. Observations were interrupted soon after this as the GRB again
went into eclipse. The next observation began at T0+10.5 ks at which
time the count rate was ~5 ct/sec but again rising in a flare which
peaked at T0+11.2 ks, at a count rate of ~20 ct/sec. This decayed to ~5
ct/sec by T0+11.6ks and then began to rise again, but the Swift
observations stopped just after this. Further observations are planned.
The time-averaged WT mode spectrum can be modelled with an absorbed
power-law with a photon index of 1.73 (+/-0.02) and an absorption
column of 6.8e21 cm^-2 at z=0.347 (Vreeswijk et al., GCN Circ. 15249)
in addition to the Galactic value of 0.17e21 cm^-2 (Kalberla et al,
2005). However as is typical during flaring episodes, there is strong
spectral evolution during the XRT observations. We therefore extracted
a further 4 spectra, one before the flares and one during each of them.
These spectra were fitted above 0.5 keV to avoid possible instrumental
effects at low energies caused by the accumulation of charge traps due
to radiation damage since the release of the current CALDB WT gain file
(version 13).
In the spectra for the first 2 flares there is evidence for additional
soft emission above the simple power-law. There are known calibration
issues which can cause bumps such as these to appear artificially (see
http://www.swift.ac.uk/analysis/xrt/digest_cal.php#abs) so we extracted
the spectra using only single-pixel events, however the soft component
is still present. It can be well modelled by adding in a thermal
component (reducing the cstat of the fits by ~120). In the first flare
this has a temperature of 33 (+/-3) eV, and in the second flare 45 (+/-
6) eV.
Details of the power-law fits are given below (for the first two flare
spectra these are the fits which include the soft component); note that
it is likely that some spectral evolution occurred during the flares,
thus these are still aggregated values. As for the time-averaged fit,
the Galactic column was fixed to 0.17e21 cm^-2 (Kalberla et al 2005)
and the free absorber was set to have a redshift of z=0.347 (GCN Circ.
15249)
Pre-flare (T0+ 150-500 s):
NH = 1.66 (+/- 0.05) e22 cm^-2
Gamma = 1.70 (+/- 0.04)
Flare 1 (T0+ 1240-1500 s)
NH = 2.2 (+/- 0.1) e22 cm^-2
Gamma = 2.28 (+/- 0.06)
Flare 2 (T0+ 4650-6100 s)
NH = 1.59 (+/- 0.07) e22 cm^-2
Gamma = 2.03 (+/- 0.04)
Flare 3 (T0+ 6700-7300 s)
NH = 1.66 (+/- 0.06) e22 cm^-2
Gamma = 1.79 (+/- 0.03)
Flare 4 (T0+11.5-12.9 ks)
NH = 1.3 (+/- 0.2) e22 cm^-2
Gamma = 2.39 (+/- 0.2)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00571830.
This circular is an official product of the Swift-XRT team.
- GCN Circular #15255
Gerard Fitzpatrick (UCD) reports on behalf of the Fermi GBM Team:
At 04:09:26.73 UT on 25 September 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB130925A (trigger 401774969/130925173),
which was also detected approximately 2 minutes later by Swift (Lien et
al., GCN 15246). The on-ground
calculated location is consistent with the Swift location. The GBM data
show that the event
was still in progress at the time of the Swift trigger. The burst was
sufficiently
bright that a Fermi Automatic Repointing Request (ARR) was triggered. This
event may
not actually be a GRB, as indicated by Burrows et al. (GCN 15253). Downlink
of the full data set for
this event was delayed due to the ARR; more details will be provided when
the data are available.
At 03:56:23.29 UT, 15 minutes prior to the GBM detection of GRB130925A,
GBM triggered and located
GBM trigger 401774186/130925164. The on-ground calculated location, using
the GBM trigger
data, is RA = 48.3 , DEC = -21.8 (J2000 degrees,
equivalent to 03h 13m, -21d 42.0'), with an uncertainty
of 12.8 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
This is also consistent with the Swift location of GRB130925A
(Lien et al., GCN 15246). The temporal and positional coincidence indicate
that this may be
a precursor pulse to GRB130925A.
The GBM light curve for this possible precursor consists of a single peak
with a duration (T90) of about 6.6 s (50-300 keV).
The time-averaged spectrum from T0-4 s to T0+2.5 s is
adequately fit by a simple power law function with index -2.25 +/- 0.07
The event fluence (10-1000 keV) in this time interval is
(6.9 +/- 0.6)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-3 s in the 10-1000 keV band is 3.0 +/- 0.2 ph/s/cm^2.
- GCN Circular #15256
J. M. Gelbord (Eureka Scientific) reports:
Historical X-ray data covering the position of GRB 130925A (Evans et al., GCN Circ 15246) is available from the ROSAT archive at HEASARC. The deepest data set is a 5.5 ks observation with the ROSAT HRI taken 1997-07-01, in which the position of GRB 130925A is 9' off axis. There is no trace of an X-ray source at this position.
Using a source extraction region of 24" and a concentric annular background region from 80" to 240", formally I find 0.2 +/- 3.6 counts in the HRI band. The three sigma upper limit is 14.8 counts (using the Bayesian approach of Kraft, Burrows & Nousek 1991, ApJ 374, 344). Given the nominal exposure time of 5.5 ks, this translates to 2.7E-03 HRI counts per sec.
We use WebPIMMS ( http://heasarc.gsfc.nasa.gov/Tools/w3pimms.html ) to convert the 3-sigma HRI count rate limit to a limit in the Swift-XRT band. Assuming the auto-generated spectral model for GRB 130925A (available from http://www.swift.ac.uk/xrt_products/00571830 ) fitted to the XRT PC-mode data for GRB 130925A (through T0+29.8 ks; NH (intrinsic) = 9.4E+21, Gamma = 2.61), together with NH (Galactic) = 1.66E+20 and z=0.347 (Vreeswijk et al., GCN Circ 15249 and Sudilovsky et al., GCN Circ 15250), the 3-sigma HRI count rate limit translates to an XRT count rate of 5.7E-3 counts per second. If we instead adopt the harder spectral model resulting from the fit to the WT-mode data (NH (Intrinsic) = 6.8E+21 and Gamma = 1.73), the equivalent XRT count rate would be 7.8E-3 counts per second.
Thus, the Rosat HRI upper limit reveals that GRB 130925A at T0+200s was at least 10^6 times brighter and at T0+30ks was still at least 100 times brighter than any X-ray source at this position in July 1997.
- GCN Circular #15257
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), D. M. Palmer (LANL),
T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC),
T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+7152 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 130925A (trigger #571830)
(Lien, et al., GCN Circ. 15246). The BAT ground-calculated position is
RA, Dec = 41.186, -26.146 deg which is
RA(J2000) = 02h 44m 44.5s
Dec(J2000) = -26d 08' 47.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 9%.
The mask-weighted light curve covers only a small part of this exceptionally
long GRB (if indeed it is a GRB at all). As reported by the Fermi-GBM team
(Fitzpatrick, GCN Circ. # 15255) the event may have begun 17 minutes prior to
the BAT trigger, and the source was still detected in BAT at T+2 hours. Thus
we cannot estimate a T90 at this time. There were multiple peaks and several
late-time flares.
In the current analysis, the burst was first detected by BAT at T-59 sec, when
the target entered the BAT field of view already emitting, and last detected by
BAT in a survey interval ending at T+7152 sec.
BAT also detected a flux increase during the first flare detected by XRT (Evans
et al. GCN Circ. # 15254) that peaked at about T+1000 seconds. BAT did not see
a significant increase at the time of the next flare (brightest in XRT), peaking
at about T+1380 seconds, though the source was still detected. BAT did strongly
detect increases during the XRT-observed flares that peaked at approximately
T+4950 and T+7100 seconds. BAT did not detect emission during another, smaller,
flare observed by XRT that peaked at about T+11000 seconds.
BAT has not detected significant flux from this location in the 15-50 keV band
prior to the current event.
The time-averaged spectrum from T-59 to T+903 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.85 +- 0.14,
and Epeak of 33.4 +- 20.0 keV (chi squared 38.18 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 4.1 +- 0.1 x 10^-05 erg/cm2
and the 1-sec peak flux measured from T-35.64 sec in the 15-150 keV band is
7.3 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index
of 2.09 +- 0.04 (chi squared 45.62 for 57 d.o.f.). The flares at T+4950 and
T+7100 seconds have photon indices in simple power-law fits of 2.19 +- 0.36
and 2.34 +- 0.28 respectively. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/571830/BA/
- GCN Circular #15258
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia=
m
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB)=
,
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC)=
,
Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UN=
AM),
Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley=
(GSFC)
report:
We observed the field of GRB 130925A (Lien, et al., GCN 15246) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional =
on
Sierra San Pedro M=E1rtir from 2013/09 25.27 to 2013/09 25.50 UTC (2.30 t=
o
7.81 hours after the BAT trigger), obtaining a total of 3.67 hours exposu=
re
in the r and i bands and 1.43 hours exposure in the Z, Y, J, and H bands.
We find an uncatalogued source in the enhanced Swift-XRT error circle
(Evans et al., GCN 15251). In comparison with USNO-B1 and 2MASS, we obta=
in
the following detections and upper limits (3-sigma):
r 22.26 +/- 0.11
i 21.75 +/- 0.10
Z 20.25 +/- 0.06
Y 20.77 +/- 0.14
J 19.98 +/- 0.07
H 19.85 +/- 0.12
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The source is spatially coincide=
nt
and about as bright as the source reported by Sudilovsky et al. (GCN
15247), which was observed minutes rather than hours after the GRB.
Further observations are planned.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro
M=E1rtir.
- GCN Circular #15259
V. Savchenko, V. Beckmann (APC), C. Ferrigno, E. Bozzo, M. Beck (ISDC),
J. Borkowski (CAMK/Torun), D. Götz (CEA/Saclay), S. Mereghettik
(INAF/IASF-Milano), A. von Kienlin, A. Rau (MPE), and K. Hurley
(SSL/Berkeley)
The possible GRB or tidal disruption event (Burrows et al, GCN 15253,
15257) 130925A, detected by Swift/BAT (Lien et al. GCN 15246, Markwardt
et al GCN 15257) and Fermi/GBM (Fitzpatrick et al, GCN 15255), has been
independently detected by the SPI Anti-Coincidence System (ACS) on-board
INTEGRAL.
The SPI-ACS light curve reveals rich multi-peak structure with a total
duration of about 5000 seconds and evolution on a time scale as small
as 2 seconds.
The initial burst, detected by Fermi/GBM at 2013-09-25T04:09:26, also
triggered SPI-ACS at 04:09:25 (T0 hereafter). The light curve displays
two fast-rise slow-decay pulses, typical for a GRB, lasting a total of
about 200 seconds and reaching a peak count rate of about 3500
counts/s (approximately corresponding to 3.5e-7 erg/cm2/s in the 75
keV-1 MeV range, Vigano' and Mereghetti 2009, arXiv:0912.5329, assuming
a GRB-like spectrum) over 1s at T0+13s.
The second episode is brighter. It starts at about T0+1800s,
(04:42:00) and lasts for ~1700 seconds with a peak count rate of about
5000 counts/s (approximately 5e-7 erg/cm2/s) over 1s at T0+2770s
(04:55:10).
We note that this episode was not observed by Swift.
The last, weaker, episode spans from ~T0+4000 to ~T0+4500 seconds with a
peak count rate of ~1000 count/s (1e-7 erg/cm2/s).
A possible precursor observed by Fermi/GBM at 03:56:23.29 (T0-900) is
not visible in the SPI-ACS data. (note, however, that Fermi/GBM is
more sensitive to photons below 100keV than SPI-ACS).
Since SPI-ACS has no imaging capabilities, it is not possible to
conclude with absolute certainty that all three episodes, spanning
over almost 5000 seconds, belong to the same source. However, a chance
temporal coincidence of these events in the SPI-ACS data is unlikely.
No strong solar activity was reported at the time of the event.
Rapid X-ray flaring detected by XRT (Evans et al, GCN 15251, Burrows
et al, GCN 15253) for at least 10000 seconds strengthens the hypothesis
that this source was active much longer than a typical GRB.
The SPI-ACS light curve of this burst, in 10s bins is available:
http://www.apc.univ-paris7.fr/~savchenk/grb130925a/grb130925a_spiacs.png
Zoomed on the first and the second peaks:
http://www.apc.univ-paris7.fr/~savchenk/grb130925a/grb130925a_spiacs_peak1.png
http://www.apc.univ-paris7.fr/~savchenk/grb130925a/grb130925a_spiacs_peak2.png
The original SPI-ACS light curve of this event is available at:
http://www.apc.univ-paris7.fr/~savchenk/grb130925a/grb130925a_spiacs.txt.gz
Arbitrary interval of the SPI-ACS light curve can be accessed with:
http://isdc.unige.ch/~savchenk/spiacs-online/spiacs-ipnlc.pl
All SPI-ACS light curves are available (both as images and data files)
at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi. The light curves,
binned at 50 ms, are derived from 91 independent detectors with
different lower energy thresholds (mainly between 50 keV and 150 keV).
SPI-ACS has no upper energy threshold and can detect photons with
energies up to at least 100 MeV. The ACS response varies as a function
of the GRB incident angle. For these reasons we caution that the count
rates cannot be easily translated into physical flux units.
- GCN Circular #15260
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline,
on behalf of the Konus-Wind team, report:
The very long GRB 130925A
(Swift-BAT trigger #571830: Lien et al., GCN 15246;
Markwardt et al., GCN 15257;
MAXI/GSC detection: Suzuki et al., GCN 15248;
Fermi/GBM detection: Fitzpatrick, GCN 15255;
INTEGRAL/SPI-ACS observation: Savchenko et al., GCN 15259)
was detected by Konus-Wind in the waiting mode.
The light curve shows several multi-peaked pulses separated
by long periods of a low-level emission with a total duration of ~4500 s.
At least three major emission episodes can be distingushed:
the first one, which triggered BAT, started at ~T0(BAT)-130 s
and lasted until ~T0(BAT)+170 s; the second, more fluent episode,
from ~T0(BAT)+1750 s to ~T0(BAT)+2950 s;
and the third, the weakest one, which onset corresponds
to the MAXI detection, from ~T0(BAT)+3730 s to ~T0(BAT)+4360 s.
The possible precursor detected by GBM is clearly seen
at ~T0(BAT)-900 s in the softest KW energy band.
As observed by Konus-Wind, the burst had a fluence of
(5.0 =B1 0.1)x10^-4 erg/cm2 and a 2.944-s peak energy flux,
measured from T0(BAT)+2548.858, of (1.0 =B1 0.03)x10^-6 erg/cm2
(both in the 20 - 10000 keV energy range).
The emission shows no signs of strong spectral variability.
Modeling the KW 3-channel time-integrated spectrum
(from T0(BAT)-120 s to T0(BAT)+4340 s) by a power law
with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha =3D -1.42 =B1 0.04, and Ep =3D 181 =B1 10 keV.
Assuming z =3D 0.347 (Vreeswijk et al., GCN 15249) and a
standard cosmology model with H_0 =3D 71 km/s/Mpc, Omega_M =3D 0.27,
Omega_Lambda =3D 0.73,
the isotropic energy release E_iso =3D (1.50 =B1 0.03)x10^53 erg,
the peak isotropic luminosity L_iso =3D (4.0 =B1 0.1)x10^50 erg,
and Ep_rest is 244 =B1 13 keV.
Thus, the prompt gamma-ray emission properties of this GRB: fluence, Ep,
and E_iso are similar to those observed in other long energetic GRBs;
the only outstanding feature of the burst is its huge duration.
In that, it resembles other ultra-long bursts: GRB 111209A at z=3D0.677
(with total duration of ~10000 s: Golenetskii et al., GCN 12663)
and GRB 121027A at z=3D1.77 (with a total duration of >4000 s: Starling e=
t al.,
in preparation).
Therefore, we suggest that the extremely rapid and dramatic X-ray flaring
observed over the first 10^4 s after the BAT trigger (Evans et al., GCN 1=
5254)
at least partially corresponds to the burst prompt emission.
All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.
The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB130925A/
- GCN Circular #15261
P. Jenke (UAH) reports on behalf of the Fermi GBM Team:
"At 04:09:26.73 UT on September 25 2013, the Fermi Gamma-Ray
Burst Monitor triggered and located
GRB 130925A (trigger 401774969/130925173),
which was also detected by Swift (Lien et al. GCN 15246)
and MAXI (Suzuki et al., GCN 15248).
The trigger resulted in an Autonomous Repoint Request (ARR)
that was accepted and the LAT slewed to the GBM in-flight
location which was consistent with the Swift/XRT position
(Evans et al. GCN 15251). The angle from the Fermi LAT boresight
is 22 deg from Swift/XRT position.
The GBM light curve consists of multiple peaks with a
duration (T90) of about 212 s (50-300 keV).
The time-averaged spectrum from T0-6 s to T0+288 s is
best fit with a power law function with an exponential high-energy
cutoff parameterized as Epeak = 107 +/- 3 keV and
an Index = -1.50 +/- 0.05.
The event fluence (10-1000 keV) in this time interval is
(2.83 +/- 0.06)E-07 erg/cm^2. The 1.0-sec peak photon flux
measured starting from T0+83 s in the 10-1000 keV band
is 11.5 +/- 0.3 ph/s/cm^2.
This event, although initially classified as a GRB, has been
shown to exhibit behavior consistent with a Tidal Disruption
Event (Burrows et al. GCN 15253). Its location suggests that
it is the same source as
GBM trigger 401774186/130925164 (G. Fitzpatrick GCN 15255).
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
- GCN Circular #15262
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),
Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM),
Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley
(GSFC)
report:
We observed the field of GRB 130925A (Lien, et al., GCN 15246) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional
on
Sierra San Pedro M=E1rtir from 2013/09 26.28 to 2013/09 26.51 UTC (26.43
to
31.98 hours after the BAT trigger), obtaining a total of 3.66 hours
exposure in the r and i bands and 1.12 hours exposure in the Z, Y, J, and
H
bands.
For the uncatalogued source in the enhanced Swift-XRT error circle (Evans
et al., GCN 15251) reported previously (Butler et al., GCN 15258), in
comparison with 2MASS, we obtain the following detections and upper limit
(3-sigma):
r 22.29 +/- 0.16
i 21.36 +/- 0.13
Z > 21.5
Y 21.28 +/- 0.29
J 19.69 +/- 0.06
H 20.02 +/- 0.17
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. Compared to our observations the
night before (GCN 15258), the source has apparently remained approximately
constant in flux in all bands. We cannot determine, as did Sudilovsky et
al. (GCN 15247), that the source is fading.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro
M=E1rtir.
- GCN Circular #15263
A. Volnova (IKI), N. Minikulov (Institute of Astrophysics), S. Abdulaev
(Institute of Astrophysics), I. Molotov (KIAM), A. Pozanenko (IKI)
report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 130925A (Lien, et al., GCN 15246) with
AZT-8 (0.7m) telescope of Gissar observatory in R filter starting on
Sep. 25 (UT) 22:15. We do not detect optical afterglow (Sudilovsky et
al., GCN 15247). A preliminary photometry of combined image is following
T_start T0+ Filter, Exposure, OT, UL(3 sigma)
(UT) (mid, d) (s)
2013-09-25T22:16:55 0.7766 R 60x60 n/d 19.9
The photometry is based on the reference star USNO-B1.0 0638-0038928
RA 02:45:02.36 Dec -26:10:50.2 (J2000), assuming R = 17.07
- GCN Circular #15264
A. Zauderer, E. Berger (Harvard), and G. Petitpas (SMA) report on behalf of
a larger collaboration:
"We observed the position of GRB 130925A (Lien et al., GCN 15246) beginning
2013 Sep 26.31 UT
(dt = 1.1 d) with the SMA at a mean frequency of 230 GHz. We find no
significant radio emission
at the position of the enhanced Swift-XRT position (Evans et al., GCN
15250) to a 3-sigma limit of 1.89 mJy.
Observations are ongoing.
We thank the SMA staff for prompt execution of these observations."
- GCN Circular #15265
A. Zauderer, E. Berger (Harvard), and G. Petitpas (SMA) report on behalf of
a larger collaboration:
"We observed the position of GRB 130925A (Lien et al., GCN 15246) beginning
2013 Sep 26.31 UT
(dt = 1.1 d) with the SMA at a mean frequency of 230 GHz. We find no
significant radio emission
at the position of the enhanced Swift-XRT position (Evans et al., GCN
15250) to a 3-sigma limit of 1.89 mJy.
Observations are ongoing.
We thank the SMA staff for prompt execution of these observations."
- GCN Circular #15266
S. T. Holland (STScI) and
A. Y. Lien (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB
130925A 157 s after the BAT trigger (Lien et al. 2013, GCNC 15246).
We do not detect any new source consistent with the GROND afterglow
position (Sudilovsky et al. 2013, GCNC 15247) in any of the UVOT
exposures. Preliminary 3-sigma upper limits, using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373),
for the finding chart and summed exposures are presented below.
---------------------------------------------------
Filter TSTART TSTOP Exposure Mag
---------------------------------------------------
white (FC) 157 306 147 >21.4
u (FC) 315 564 246 >20.6
---------------------------------------------------
v 645 7269 381 >20.0
b 571 6121 170 >20.6
u 719 5983 274 >20.4
uvw1 5579 11,956 701 >21.1
uvm2 5374 11,436 1082 >21.2
uvw2 4964 7136 393 >20.7
white 595 6929 618 >22.0
---------------------------------------------------
The quoted upper limits have not been corrected for the expected
extinction due to the Galactic reddening along the line of sight to
this burst of E(B-V) = 0.02 mag (Schlafly et al. 2011, ApJS, 737,
103).
- GCN Circular #15267
S. T. Holland (STScI)
reports on behalf of the Swift/UVOT team:
Deep Swift/UVOT imaging taken between 157 s and 184.8 ks after
the BAT trigger (Lien et al, 2013, GCNC 15246) shows a faint source at
the location of the GROND detection (Sudilovsky et al. 2013, GCNC
15247). This source has a preliminary magnitude, on the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373),
of white = 22.9 +/- 0.3 mag and is detected with a significance of 4.7
sigma. This magnitude has not been corrected for the expected
extinction due to the Galactic reddening along the line of sight to
this burst of E(B-V) = 0.02 mag (Schlafly et al. 2011, ApJS, 737,
103). The total white exposure time is 18 ks. There is no evidence
for variability.
The probability of finding a galaxy of this apparent luminosity
within the UVOT-enhanced XRT error circle (Evans et al. 2013, GCNC
15251) is 0.01 using the method of Bloom et al. (2002, AJ, 423, 1111).
The positional coincidence and lack of variability suggest that this
is the host galaxy of GRB 130925A. There is no evidence in the UVOT
data that this source has any extended structure.
- GCN Circular #15268
D. Kocevski, J. Racusin (NASA/GSFC), G. Vianello (Stanford), M. Axelsson
(Stockholm University), Nicola Omodei (Stanford) report on behalf of the
Fermi-LAT team:
A preliminary examination of the Fermi LAT data of the field containing GRB
130925A (Lien, et al., GCN 15246) has revealed no significant emission
above 40 MeV. The GRB was located ~22 degrees away from the LAT boresight
at the time of the first GBM detected emission associated with this burst
at 03:56:23.29 UT on 25 September 2013 (GCN 15255), hereafter T0(GBM), and
the subsequent autonomous repoint ensured that the source remained in the
field-of-view for the next ~2000s until it was occulted by the Earth.
Using an unbinned likelihood analysis, we estimate the following LAT upper
limits at 95% confidence for three separate time intervals, one covering
the entire 2000s that the source stayed in the LAT field-of-view, and two
of which correspond to the first and third emission episodes detected by
INTEGRAL/SPI-ACS (GCN 15259) and Konus-Wind (GCN 15260). We note that the
source was not in the LAT field-of-view during the second interval reported
in GCNs 15259 & 15260.
Interval 1: T0(GBM) to T0(GBM)+2000 = 7.3e-07 photons cm-2 s-1 (4.8e-10
ergs cm-2 s-1)
Interval 2: T0(GBM)+900s to T0(GBM)+1100s = 5.5e-06 photons cm-2 s-1
(3.6e-09 ergs cm-2 s-1)
Interval 3: T0(GBM)+4900 to T0(GBM)+5400 = 2.5e-06 photons cm-2 s-1
(1.6e-09 ergs cm-2 s-1)
This analysis covers an energy range of 0.1 to 10 GeV with a 12 deg
extraction region centered on the best known source position (GCN 15246).
The upper limits are computed using the P7SOURCE_V6 instrument response
functions, where we assume a power-law source spectrum fixed to a photon
index of -2.1, reflecting a typical value for high-energy emission in GRBs.
For reference, T0(GBM) = T0(BAT)-900s.
The Fermi LAT point of contact for this burst is Magnus Axelsson (
magnusa@astro.su.se).
The Fermi LAT is a pair conversion telescope designed to cover the energy
band from 20 MeV to greater than 300 GeV. It is the product of an
international collaboration between NASA and DOE in the U.S. and many
scientific institutions across France, Italy, Japan and Sweden.
- GCN Circular #15278
K. Hurley, on behalf of the IPN team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline, on behalf of the Konus-Wind team,
I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,
W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team,
D. M. Smith, J. McTiernan, R. Schwartz, W.
Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro,
Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team,
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of
the Swift-BAT team,
J. Goldsten, on behalf of the MESSENGER NS GRB team, and
V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa, on behalf of the Fermi
GBM team, report:
Eight IPN spacecraft observed GRB 130925A (Lien et al. GCN 15246,
Markwardt et al. 15247). When the responses of all the spacecraft are
considered, the IPN had an uninterrupted view of this event from
roughly 900 s before the Swift BAT trigger, to ~7100 s after it.
Constraints on the arrival directions of the four main emission
episodes strengthen the case for their common origin, as suggested by
Savchenko et al. (GCN 15259). The following table details the
observations. The times are relative to the BAT trigger at 15084 s UT
(04:11:24). N/O means the episode was not observable.
----------------------------------------------------------------------------
Instrument/ | Precursor | 1st | 2nd | 3rd
spacecraft | -900 s | episode | episode | episode*
| | -130 -> +170 s|+1750 -> +2950 s|+3730 -> +4360 s
----------------------------------------------------------------------------
Swift BAT No Trig N/O No
Fermi GBM Trig Trig N/O No
INTEGRAL SPI-ACS No Yes Yes Yes
Konus Wind Yes Yes Yes Yes
MESSENGER No Yes Yes No
Mars Odyssey No N/O Yes No
Suzaku WAM No No Yes No
RHESSI Yes Yes N/O No
------------------------------------------------------------------------------
*also observed and localized by MAXI (Suzuki et al. GCN 15248)
We conclude from these observations that the total duration of this
event in >25 keV gamma-rays above the IPN flux/fluence threshold was
at least 5260 s, and ~7150 s long when the later episodes, observed only
by BAT (GCN 15257), are included.
- GCN Circular #15280
D. Malesani (DARK/NBI), S. B. Cenko (NASA/GSFC), D. N. Burrows (PSU), A.
Y. Lien (NASA/GSFC/ORAU), P. A. Evans (U. Leicester), and N. Gehrels
(NASA/GSFC) report:
Swift has been continuously monitoring the X-ray counterpart of GRB
130925A (Lien et al., GCN 15246), with data currently extending up to
512 ks after the trigger. The intense X-ray flaring activity reported by
Burrows et al. (GCN 15253) and Evans et al. (GCN 15254) ceased between
12 and 28 ks after the trigger. The X-ray light curve from 27.9 to 512.4
ks can be modelled with an initial power-law decay with an index of
alpha = 0.84 +/- 0.03, followed by a possible break at 310 (+60, -50) ks
to an alpha of 1.38 (+0.47, -0.23). The updated X-ray light curve is
available at the following URL:
http://www.swift.ac.uk/xrt_curves/00571830/
While the duration of the prompt emission and the flaring activity are
extraordinary among GRBs (Suzuki et al., GCN 15248; Fitzpatrick, GCN
15255; Markwardt et al., GCN 15257; Savchenko et al., GCN 15259;
Golenetskii et al., GCN 15260; Jenke, GCN 15261; Hurley et al., GCN
15278), the late-time behaviour is typical of long-duration GRB
afterglows, and quite different from that of the TDE Swift J1644+57,
which showed continuous flares and dips, with no regular power-law decay
(e.g. Burrows et al. 2011, Nat, 476, 421). There is also no prior
detection of the source in BAT before the trigger (Markwardt et al., GCN
15257).
The extremely long-lived high-energy emission coupled with the
relatively steady power-law X-ray decay at t > 20 ks is reminiscent of
the so-called "ultra-long" GRBs (Levan et al. 2013, arXiv:1302.2352),
including GRB 101225A (Thoene et al. 2011, Nat, 480, 72; Campana et al.
2011, Nat, 480, 69), GRB 111209A (Gendre et al. 2013, ApJ, 766, 30), and
GRB 121027A. The origin of these events and their relation to
traditional long-duration GRBs (i.e., the core-collapse of a massive
star) remain controversial, so we encourage continued multi-wavelength
follow-up of this object.
- GCN Circular #15286
E. C. Bellm, F. A. Harrison, K. Forster, K. K. Madsen, V. Rana
(Caltech), S. E. Boggs, J. Tomsick (U.C. Berkeley), J. M. Miller
(Michigan), and S. B. Cenko (NASA/GSFC) report on behalf of the NuSTAR
collaboration:
NuSTAR observed the unusual ultra-long GRB/TDE candidate GRB 130925A
(GCN 15246) beginning 44.3 hours after the Swift trigger for a total
of 39.2 ksec exposure time.
NuSTAR detects the source to >20 keV; the average 3-20 keV flux over
the interval was 1.3E-12 erg/cm^-2/s^-1. The data may be fit with an
absorbed power law with spectral index Gamma ~ 3.
NuSTAR observes a broad absorption feature centered near 6 keV.
Simultaneous Swift-XRT spectra support the existence of this feature
at lower SNR. An F-test of a Gaussian absorption feature fit to the
combined data sets yields a detection significance of 5.5 sigma.
Preliminary searches for features in the early-time XRT data have not
identified any clear signatures; additional tests are ongoing.
Further observations are in progress; we encourage continued
monitoring of this interesting event at all wavelengths.
We thank the NuSTAR Mission Operations Team for the rapid turnaround
that enabled this observation.
- ATEL #5435
Title: NuSTAR observations of GRB 130925A
Author: E. C. Bellm, F. A. Harrison, K. Forster, K. K. Madsen, V.
Rana (Caltech), S. E. Boggs, J. Tomsick (U. C. Berkeley), J. M. Miller
(Michigan), and S. B. Cenko (NASA/GSFC) on behalf of the NuSTAR collaboration
Queries: jtomsick@ssl.berkeley.edu
Posted: 1 Oct 2013; 22:37 UT
Subjects:X-ray, Gamma-Ray Burst
NuSTAR observed the unusual ultra-long GRB/TDE candidate GRB 130925A (GCN
15246) beginning 44.3 hours after the Swift trigger for a total of 39.2
ksec exposure time.
NuSTAR detects the source to >20 keV; the average 3-20 keV flux over the
interval was 1.3E-12 erg/cm^-2/s^-1. The data may be fit with an absorbed
power law with spectral index Gamma ~ 3.
NuSTAR observes a broad absorption feature centered near 6 keV. Simultaneous
Swift-XRT spectra support the existence of this feature at lower SNR.
An F-test of a Gaussian absorption feature fit to the combined data sets
yields a detection significance of 5.5 sigma. Preliminary searches for
features in the early-time XRT data have not identified any clear signatures;
additional tests are ongoing.
Further observations are in progress; we encourage continued monitoring
of this interesting event at all wavelengths.
We thank the NuSTAR Mission Operations Team for the rapid turnaround that
enabled this observation.
- GCN Circular #15299
A. J. Castro-Tirado (IAA-CSIC Granada and Univ. de M=E1laga), M. Bremer,
J.-M. Winters and S. Koenig (IRAM Grenoble), on behalf of a large
collaboration, report:
"Following the detection of the extraordinarily long event GRB 130925A/Sw
J0244-2609 by Swift (Lien et al. 2013, GCN 15247) we attempted on Oct 1
(00:30 UT) millimetre observations with the Plateu de Bure Interferometer
(PdBI) in the French Alps, in 6-antenna compact D configuration. Due to
the low declination, the source was lost for two antennas due to shadowing
effects by other antenna. No mm source is detected, with a 3 sigma limit
of 0.58 mJy at 86 GHz. This value is a factor of 30 times less than the
measured flux density for the tidal disruption flare candidate GRB
110328A/Sw J1644+5734 with PdBI one week post burst (Castro-Tirado et al.
2013, RMxAC 42, 36)."
- GCN Circular #15301
B. A. Zauderer, E. Berger, T. Laskar (Harvard) report on behalf of a larger
collaboration
as part of the CARMA Key Project "A Millimeter View of the Transient
Universe":
"We observed the position of GRB 130925A (Lien et al., GCN 15246) with the
Combined Array for Research in Millimeter Astronomy (CARMA) beginning
2013 Sep 26.36 (dt = 1.19 d) at a mean frequency of 93 GHz. Observations
were
conducted in the compact E configuration, with significant flagging for
shadowed
antennas required. We do not detect any significant radio emission to a
3-sigma
limit of 0.6 mJy at the position of the Swift-XRT position (Evans et al.,
GCN 15251).
We thank the CARMA observers and staff for prompt execution of these
observations."
- GCN Circular #15322
R. Ruffini, C.L. Bianco, M. Enderli, M. Muccino, A.V. Penacchioni, G.B.
Pisani, J.A. Rueda, N. Sahakyan, Y. Wang, L.Izzo report:
The observed X-ray emission in the afterglow of GRB 130925A (Lien et al., GCN 15247; Fitzpatrick et al., GCN 15255) presents an unprecedented sequence of flares departing from the canonical single power law decay (L \propto t^{-1.5}) observed in energetic GRBs-SNe (the "golden sample", Pisani et al. 2013, A&A 552, L5, arXiv:1304.1764). Correspondingly the X-ray Luminosity after 2*10^4 s in the rest-frame of the burst is almost constant (L \propto t^{-0.3}) and the energy emitted is a factor 30 larger than in the golden sample.
In the Induced Gravitational Collapse (IGC) paradigm, after the "input" due to a supernova explosion and the Black Hole formation (Ruffini 2013, IJMPD, 22, 1360009, arXiv:1310.1836), the "output" of a newly born Neutron Star from the Supernova and the Black Hole may remain bound in an elliptical orbit. This can explain the repeated flaring activity and the source of the larger observed energy.
In the canonical IGC scenario at z = 0.35 (Sudilovsky et al., GCN 15250, Vreeswijk et al., GCN 15249), assuming a 1998bw-like SN, a supernova should be expected to peak around the 10 - 16 October. It is crucial to perform optical observations in order to find out if the presence of the above mentioned binary nature in the "output" can modify the canonical scenario. Periodicities on time scales down to few minutes should be explored.
- ATEL #5531
K. Bannister, P. Hancock, S. Kulkarni, A. Horesh, A. Zauderer, T. Murphy, B. Gaensler
We observed the long GRB/TDE candidate GRB130925A (GCN 15246, Atel# 5435)
with the Australia Telescope Compact Array (ATCA) on the dates and frequencies
as shown below. ATCA was in in the H264 configuration and 2 GHz bandwidth
was used for each frequency.
GRB130925A was detected at all bands and epochs, although some detections
are < 5 sigma
0237-233 was used as a phase calibrator for all observations.
The following flux densities and errors were obtained by fitting a synthesized
beam to the cleaned maps:
2013 Oct 09.9
Freq (GHz) Flux density (uJy)
5.5 167 +- 15 [Note 1]
9 138 +- 14
17 186 +- 14
19 160 +- 13
2013 Oct 14.9
Freq (GHz) Flux density (uJy)
5.5 84 +- 27
9 188 +- 47
2013 Oct 15.9 [Note 2]
Freq (GHz) Flux density (uJy)
17 177 +-51
19 178 +-52
Note 1: Occasional bandpass ripple was observed at 5.5 GHz on Antenna 4.
When antenna 4 was removed from the imaging, GRB130925A was not detected.
This measurement should be considered suspect.
Note 2: 0537-441 was used as a bandpass and flux calibrator for this
observation.
0537-441 has not been referenced to the ATCA primary flux calibrator (1934-638)
since 2013-05-11, so the absolute flux calibration could be in error by
as much as 20%.
We thank the ATCA staff for facilitating these observations.
- GCN Circular #15489
N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), R. Hounsell,
A. S. Fruchter (STScI), S. B. Cenko (NASA/GSFC), D. A. Perley (Caltech),
P. T. O'Brien (U. Leicester) report:
We imaged the location of GRB 130925A (Evans et al. GCN 15251;
Sudilovsky et al. GCN 15247) with HST at two epochs, at 20 days and
47 days post-burst respectively, in the F814W (I-band), F110W (J-band)
and F160W (H-band) filters.
The host galaxy is well resolved and appears to be an almost edge-on spiral.
The galaxy shows signs of disturbance: specifically the disk shows asymmetry
and the bulge appears to be extended perpendicular to the disk, suggestive
of a polar-ring morphology.
Image subtraction reveals evidence of faint transient light in the first epoch
in all three filters. The location is in good agreement with that from prior
ground-based imaging of the GRB. The transient position is close to the disk
plane, which likely accounts for the high extinction and X-ray column for this
event (Evans et al. GCN 15254). It is, however, slightly offset from the
nucleus of the galaxy by about 0.12 arcsec (~600pc in projection). This
would initially seem to be in conflict with a possible tidal disruption origin
for this event, although if the galaxy morphology is indicative of a recent
major merger, then it is plausible that the system currently contains more
than one super-massive black hole.
Further analysis is ongoing.
We thank the staff at STScI for approving and expediting
these ToO observations.
- 1401.2699 from 14 Jan 14
Shu-Jin Hou et al.: Time evolution of flares in GRB 130925A: jet precession in black hole accretion system
GRB 130925A, composed of three gamma-ray emission episodes and a series of orderly flares, has been detected by $Swift$, Fermi, Konus-$Wind$,
and $INTEGRAL$. If the third weakest gamma-ray episode can be considered as a giant flare, we find that after the second gamma-ray episode
observed by $INTEGRAL$ located at about 2000 s, there exists a positive relation between the time intervals of the adjacent flares and the time
since the episode. We suggest that the second gamma-ray episode and its flares originate from the resumption of the accretion process due to
the fragments from the collapsar falling back, such a relation may be related to a hyperaccretion disk around a precessed black hole (BH). We
propose that the origin and time evolution of the flares, and the approximately symmetrical temporal structure and spectral evolution of the
single flare, can be explained well by the jet precession model \citep{Liu2010}. In addition, the mass and spin of the BH can be constrained,
which indicates a stellar-mass, fast rotating BH located in the center of GRB 130925A.
- 1402.6755 from 28 Feb 14
Eric C. Bellm et al.: X-ray Spectral Components in the Afterglow of GRB 130925A
We have identified spectral features in the late-time X-ray afterglow of the unusually long, slow-decaying GRB 130925A using NuSTAR, Swift-XRT,
and Chandra. A spectral component in addition to an absorbed power-law is required at $>4\sigma$ significance, and its spectral shape varies
between two observation epochs at $2\times10^5$ and $10^6$ seconds after the burst. Several models can fit this additional component, each with
very different physical implications. A broad, resolved Gaussian absorption feature of several keV width improves the fit, but it is poorly
constrained in the second epoch. An additive black body or second power-law component provide better fits. Both are challenging to interpret:
the blackbody radius is near the scale of a compact remnant ($10^8$ cm), while the second powerlaw component requires an unobserved high-energy
cutoff in order to be consistent with the non-detection by Fermi-LAT.
- 1403.3825 from 18 Mar 14
Yi-Nan Zhao et al.: Spectral Softening in X-ray Afterglow of GRB 130925A as Predicted by Dust Scattering Model
Gamma-ray bursts (GRBs) usually occurs in a dense star-forming region with massive circum-burst medium. The small-angle scattering of intense
prompt X-ray emission off the surrounding dust grains will have observable consequences, and sometimes can dominate the X-ray afterglow. In
most of the previous studies, only Rayleigh-Gans (RG) approximation is employed for describing the scattering process, which works accurately
for the typical size of grains (with radius $a\leq 0.1\,{\rm \mu m}$) in the diffuse interstellar medium. When the size of the grains may
significantly increase as in a more dense region where GRBs would occur, the RG approximation may not be valid enough for modeling detailed
observational data. In order to study the temporal and spectral properties of the scattered X-ray emission more accurately with potentially
larger dust grains, we provide a practical approach using the series expansions of anomalous diffraction (AD) approximation based on the
complicated Mie theory. We apply our calculations to understanding the puzzling X-ray afterglow of recently observed GRB 130925A which showed a
significant spectral softening. We find that the X-ray scattering scenarios with either AD or RG approximation adopted could both well
reproduce the temporal and spectral profile simultaneously. Given the plateau present in early X-ray light curve, a typical distribution of
smaller grains as in the interstellar medium would be suggested for GRB 130925A.
- 1403.4079 from 18 Mar 14
P.A. Evans et al.: GRB 130925A: an ultra-long Gamma Ray Burst with a dust-echo afterglow, and implications for the origin of the ultra-long GRBs
GRB~130925A was an unusual GRB, consisting of 3 distinct episodes of high-energy emission spanning $\sim$20 ks, making it a member of the
proposed category of `ultra-long' bursts. It was also unusual in that its late-time X-ray emission observed by \swift\ was very soft, and
showed a strong hard-to-soft spectral evolution with time. This evolution, rarely seen in GRB afterglows, can be well modelled as the
dust-scattered echo of the prompt emission, with stringent limits on the contribution from the normal afterglow (i.e. external shock) emission.
We consider and reject the possibility that GRB~130925A was some form of tidal disruption event, and instead show that if the circumburst
density around GRB~130925A is low, the long duration of the burst and faint external shock emission are naturally explained. Indeed, we suggest
that the ultra-long GRBs as a class can be explained as those with low circumburst densities, such that the deceleration time (at which point
the material ejected from the nascent black hole is decelerated by the circumburst medium) is $\sim$20 ks, as opposed to a few hundred seconds
for the normal long GRBs.
- GCN Report 465.1
GCN_Report 465.1 has been posted:
http://gcn.gsfc.nasa.gov/reports/report_465_1.pdf
by A.Y. Lien
at NAsA/GSFC/ORAU
titled: "Swift Observations of GRB 130925A"
- 1405.2897 from 13 May 14
Luigi Piro et al.: A hot cocoon in the ultralong GRB 130925A: hints of a PopIII-like progenitor in a low density wind environment
GRB 130925A is a peculiar event characterized by an extremely long gamma-ray duration ($\approx$7 ks), as well as dramatic flaring in the
X-rays for $\approx$20 ks. After this period, its X-ray afterglow shows an atypical soft spectrum with photon index $\Gamma$$\sim$4, as
observed by Swift and Chandra, until $\approx 10^7$ s, when XMM-Newton observations uncover a harder spectral shape with $\Gamma$$\sim$2.5,
commonly observed in GRB afterglows. We find that two distinct emission components are needed to explain the X-ray observations: a thermal
component, which dominates the X-ray emission for several weeks, and a non-thermal component, consistent with a typical afterglow. A forward
shock model well describes the broadband (from radio to X-rays) afterglow spectrum at various epochs. It requires an ambient medium with a very
low density wind profile, consistent with that expected from a low-metallicity blue supergiant (BSG). The thermal component has a remarkably
constant size and a total energy consistent with those expected by a hot cocoon surrounding the relativistic jet. We argue that the features
observed in this GRB (its ultralong duration, the thermal cocoon, and the low density wind environment) are associated with a low metallicity
BSG progenitor and, thus, should characterize the class of ultralong GRBs.
- 1407.4210 from 17 Jul 14
J. Greiner et al.: GROND coverage of the main peak of Gamma-Ray Burst 130925A
Prompt or early optical emission in gamma-ray bursts is notoriously difficult to measure, and observations of the dozen cases show a large
variety of properties. Yet, such early emission promises to help us achieve a better understanding of the GRB emission process(es).
We performed dedicated observations of the ultra-long duration (T90 about 7000 s) GRB 130925A in the optical/near-infrared with the 7-channel
"Gamma-Ray Burst Optical and Near-infrared Detector" (GROND) at the 2.2m MPG/ESO telescope. We detect an optical/NIR flare with an amplitude of
nearly 2 mag which is delayed with respect to the keV--MeV prompt emission by about 300--400 s. The decay time of this flare is shorter than
the duration of the flare (500 s) or its delay.
While we cannot offer a straightforward explanation, we discuss the implications of the flare properties and suggest ways toward understanding it.
- 1505.03296 from 14 May 15
Rupal Basak et al.: Thermal Emissions Spanning the Prompt and the Afterglow Phase of the Ultra-long GRB 130925A
GRB 130925A is an ultra-long GRB, and it shows clear evidences for a thermal emission in the soft X-ray data of \emph{Swift}/XRT
($\sim0.5$\,keV), lasting till the X-ray afterglow phase. Due to the long duration of the GRB, the burst could be studied in hard X-rays with
high-resolution focusing detectors (\emph{NuSTAR}). The blackbody temperature, as measured by the \emph{Swift}/XRT, shows a decreasing trend
till the late phase (Piro et al. 2014) whereas the high-energy data reveals a significant blackbody component during the late epochs at an
order of magnitude higher temperature ($\sim5$\,keV), as compared to the contemporaneous low energy data (Bellm et al. 2014). We resolve this
apparent contradiction by demonstrating that a model with two black bodies and a power-law (2BBPL) is consistent with the data right from the
late prompt emission to the afterglow phase. Both the blackbodies show a similar cooling behaviour upto the late time. We invoke a structured
jet, having a fast spine and a slower sheath layer, to identify the location of these blackbodies. Independent of the physical interpretation,
we propose that the 2BBPL model is a generic feature of the prompt emission of all long GRBs, and the thermal emission found in the afterglow
phase of different GRBs reflects the lingering thermal component of the prompt emission with diverse time-scales. We strengthen this proposal
by pointing out a close similarity between the spectral evolutions of this GRB and GRB~090618, a source with significant wide band data during
the early afterglow phase.
- 1506.00636 from 3 Jun 15
Assaf Horesh et al.: The unusual radio afterglow of the ultra-long gamma-ray burst GRB 130925A
GRB 130925A is one of the recent additions to the growing family of ultra-long GRBs (T90$ \gtrsim 1000$ s). While the X-ray emission of
ultra-long GRBs have been studied extensively in the past, no comprehensive radio dataset has been obtained so far. We report here the early
discovery of an unusual radio afterglow associated with the ultra-long GRB 130925A. The radio emission peaks at low-frequencies ($\sim 7$ GHz)
at early times, only $2.2$ days after the burst occurred. More notably, the radio spectrum at frequencies above $10$ GHz exhibits a rather
steep cut-off, compared to other long GRB radio afterglows. This cut-off can be explained if the emitting electrons are either mono-energetic
or originate from a rather steep, $dN/dE \propto E^{-4}$, power-law energy distribution. An alternative electron acceleration mechanism may be
required to produce such an electron energy distribution. Furthermore, the radio spectrum exhibits a secondary underlying and slowly varying
component. This may hint that the radio emission we observed is comprised of emission from both a reverse and a forward shock. We discuss our
results in comparison with previous works that studied the unusual X-ray spectrum of this event and discuss the implications of our findings on
progenitor scenarios.
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