- GCN/BACODINE POSITION NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 27 Oct 15 22:42:54 UT
NOTICE_TYPE: Swift-BAT GRB Position
TRIGGER_NUM: 661869, Seg_Num: 0
GRB_RA: 76.238d {+05h 04m 57s} (J2000),
76.431d {+05h 05m 43s} (current),
75.628d {+05h 02m 31s} (1950)
GRB_DEC: -6.427d {-06d 25' 35"} (J2000),
-6.406d {-06d 24' 21"} (current),
-6.494d {-06d 29' 39"} (1950)
GRB_ERROR: 3.00 [arcmin radius, statistical only]
GRB_INTEN: 0 [cnts] Image_Peak=1393 [image_cnts]
TRIGGER_DUR: 120.000 [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: 17322 TJD; 300 DOY; 15/10/27
GRB_TIME: 81640.66 SOD {22:40:40.66} UT
GRB_PHI: 118.21 [deg]
GRB_THETA: 37.36 [deg]
SOLN_STATUS: 0x13
RATE_SIGNIF: 0.00 [sigma]
IMAGE_SIGNIF: 8.49 [sigma]
MERIT_PARAMS: +1 +0 +0 +7 +1 -1 +0 +0 +66 +0
SUN_POSTN: 211.94d {+14h 07m 44s} -12.92d {-12d 54' 53"}
SUN_DIST: 131.76 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 38.94d {+02h 35m 45s} +11.76d {+11d 45' 46"}
MOON_DIST: 41.48 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.29,-26.57 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 74.30,-29.12 [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 = 125.17,11.17 [deg].
- red DSS finding chart
ps-file
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 27 Oct 15 22:44:36 UT
NOTICE_TYPE: Swift-XRT Position
TRIGGER_NUM: 661869, Seg_Num: 0
GRB_RA: 76.2188d {+05h 04m 52.51s} (J2000),
76.4118d {+05h 05m 38.84s} (current),
75.6090d {+05h 02m 26.15s} (1950)
GRB_DEC: -6.4496d {-06d 26' 58.5"} (J2000),
-6.4288d {-06d 25' 43.5"} (current),
-6.5174d {-06d 31' 02.4"} (1950)
GRB_ERROR: 6.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN: 5.37e-10 [erg/cm2/sec]
GRB_SIGNIF: 5.38 [sigma]
IMG_START_DATE: 17322 TJD; 300 DOY; 15/10/27
IMG_START_TIME: 81844.05 SOD {22:44:04.05} UT, 203.4 [sec] since BAT Trigger Time
TAM[0-3]: 327.62 237.21 261.62 243.41
AMPLIFIER: 2
WAVEFORM: 134
SUN_POSTN: 211.94d {+14h 07m 45s} -12.92d {-12d 54' 55"}
SUN_DIST: 131.77 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 38.96d {+02h 35m 50s} +11.77d {+11d 46' 02"}
MOON_DIST: 41.46 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.30,-26.60 [deg] galactic lon,lat of the burst
ECL_COORDS: 74.28,-29.14 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Coordinates.
COMMENTS: The XRT position is 1.76 arcmin from the BAT position.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 27 Oct 15 22:44:46 UT
NOTICE_TYPE: Swift-XRT Image
TRIGGER_NUM: 661869, Seg_Num: 0
GRB_RA: 76.2188d {+05h 04m 52.5s} (J2000),
76.4118d {+05h 05m 38.8s} (current),
75.6090d {+05h 02m 26.1s} (1950)
GRB_DEC: -6.4496d {-06d 26' 58.5"} (J2000),
-6.4288d {-06d 25' 43.5"} (current),
-6.5174d {-06d 31' 02.4"} (1950)
GRB_ERROR: 6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 29 [cnts]
IMG_START_DATE: 17322 TJD; 300 DOY; 15/10/27
IMG_START_TIME: 81844.05 SOD {22:44:04.05} UT, 203.4 [sec] since BAT Trigger Time
CENTROID_X: 343.71, raw= 344 [pixels]
CENTROID_Y: 274.21, raw= 274 [pixels]
ROLL: 113.76 [deg]
GAIN: 1
MODE: 3, Long Image mode
WAVEFORM: 134
EXPO_TIME: 2.50 [sec]
GRB_POS_XRT_Y: -55.59
GRB_POS_XRT_Z: 90.56
IMAGE_URL: sw00661869000msxps_rw.img
SUN_POSTN: 211.94d {+14h 07m 45s} -12.92d {-12d 54' 55"}
SUN_DIST: 131.77 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 38.96d {+02h 35m 50s} +11.77d {+11d 46' 04"}
MOON_DIST: 41.46 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.30,-26.60 [deg] galactic lon,lat of the burst
ECL_COORDS: 74.28,-29.14 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 27 Oct 15 22:44:54 UT
NOTICE_TYPE: Swift-XRT Processed Image
TRIGGER_NUM: 661869, Seg_Num: 0
GRB_RA: 76.2188d {+05h 04m 52.5s} (J2000),
76.4118d {+05h 05m 38.8s} (current),
75.6090d {+05h 02m 26.1s} (1950)
GRB_DEC: -6.4496d {-06d 26' 58.5"} (J2000),
-6.4288d {-06d 25' 43.5"} (current),
-6.5174d {-06d 31' 02.4"} (1950)
GRB_ERROR: 6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN: 29 [cnts]
IMG_START_DATE: 17322 TJD; 300 DOY; 15/10/27
IMG_START_TIME: 81844.05 SOD {22:44:04.05} UT, 203.4 [sec] since BAT Trigger Time
CENTROID_X: 343.71, raw= 344 [pixels]
CENTROID_Y: 274.21, raw= 274 [pixels]
ROLL: 113.76 [deg]
GAIN: 1
MODE: 3, Long Image mode
WAVEFORM: 134
EXPO_TIME: 2.50 [sec]
GRB_POS_XRT_Y: -55.59
GRB_POS_XRT_Z: 90.56
IMAGE_URL: sw00661869000msxps_rw.img
SUN_POSTN: 211.94d {+14h 07m 45s} -12.92d {-12d 54' 55"}
SUN_DIST: 131.77 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 38.96d {+02h 35m 50s} +11.77d {+11d 46' 05"}
MOON_DIST: 41.46 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.30,-26.60 [deg] galactic lon,lat of the burst
ECL_COORDS: 74.28,-29.14 [deg] ecliptic lon,lat of the burst
COMMENTS: SWIFT-XRT Processed Image.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 27 Oct 15 22:45:47 UT
NOTICE_TYPE: Swift-BAT GRB Lightcurve
TRIGGER_NUM: 661869, Seg_Num: 0
GRB_RA: 76.238d {+05h 04m 57s} (J2000),
76.431d {+05h 05m 43s} (current),
75.628d {+05h 02m 31s} (1950)
GRB_DEC: -6.427d {-06d 25' 35"} (J2000),
-6.406d {-06d 24' 21"} (current),
-6.494d {-06d 29' 39"} (1950)
GRB_DATE: 17322 TJD; 300 DOY; 15/10/27
GRB_TIME: 81640.66 SOD {22:40:40.66} UT
TRIGGER_INDEX: 20000
GRB_PHI: 118.21 [deg]
GRB_THETA: 37.36 [deg]
DELTA_TIME: 0.00 [sec]
TRIGGER_DUR: 120.000 [sec]
SOLN_STATUS: 0x13
RATE_SIGNIF: 0.00 [sigma]
IMAGE_SIGNIF: 8.49 [sigma]
LC_URL: sw00661869000msb.lc
SUN_POSTN: 211.94d {+14h 07m 45s} -12.92d {-12d 54' 56"}
SUN_DIST: 131.76 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 38.97d {+02h 35m 52s} +11.77d {+11d 46' 13"}
MOON_DIST: 41.46 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.29,-26.57 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 74.30,-29.12 [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 = 125.17,11.17 [deg].
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 27 Oct 15 22:51:15 UT
NOTICE_TYPE: Swift-UVOT Source List
TRIGGER_NUM: 661869, Seg_Num: 0
POINT_RA: 76.248d {+05h 05m 00s} (J2000)
POINT_DEC: -6.446d {-06d 26' 43"} (J2000)
POINT_ROLL: 113.757d
IMG_START_DATE: 17322 TJD; 300 DOY; 15/10/27
IMG_START_TIME: 81850.17 SOD {22:44:10.17} UT, 209.5 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 6.619
N_STARS: 44
X_OFFSET: 312 [pixels]
Y_OFFSET: 528 [pixels]
X_MAX: 1271 [pixels]
Y_MAX: 1487 [pixels]
DET_THRESH: 22
PHOTO_THRESH: 13
SL_URL: sw00661869000msufc0209.fits
SUN_POSTN: 211.94d {+14h 07m 46s} -12.92d {-12d 55' 01"}
SUN_DIST: 131.74 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 39.02d {+02h 36m 06s} +11.78d {+11d 47' 03"}
MOON_DIST: 41.43 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.32,-26.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 74.31,-29.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Source List.
- GCN NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Tue 27 Oct 15 22:51:58 UT
NOTICE_TYPE: Swift-UVOT Processed Source List
TRIGGER_NUM: 661869, Seg_Num: 0
POINT_RA: 76.248d {+05h 05m 00s} (J2000)
POINT_DEC: -6.446d {-06d 26' 43"} (J2000)
POINT_ROLL: 113.757d
IMG_START_DATE: 17322 TJD; 300 DOY; 15/10/27
IMG_START_TIME: 81850.17 SOD {22:44:10.17} UT, 209.5 [sec] since BAT Trigger Time
FILTER: 10, White
BKG_MEAN: 6.619
N_STARS: 44
X_OFFSET: 312 [pixels]
Y_OFFSET: 528 [pixels]
X_MAX: 1271 [pixels]
Y_MAX: 1487 [pixels]
DET_THRESH: 22
PHOTO_THRESH: 13
SL_URL: sw00661869000msufc0209.fits
SUN_POSTN: 211.94d {+14h 07m 46s} -12.92d {-12d 55' 01"}
SUN_DIST: 131.75 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 39.03d {+02h 36m 08s} +11.79d {+11d 47' 10"}
MOON_DIST: 41.42 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.32,-26.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 74.31,-29.14 [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: Tue 27 Oct 15 22:53:00 UT
NOTICE_TYPE: Swift-UVOT Image
TRIGGER_NUM: 661869, Seg_Num: 0
POINT_RA: 76.248d {+05h 05m 00s} (J2000)
POINT_DEC: -6.446d {-06d 26' 43"} (J2000)
ROLL: 113.757d
IMG_START_DATE: 17322 TJD; 300 DOY; 15/10/27
IMG_START_TIME: 81850.17 SOD {22:44:10.17} UT, 209.5 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 467678665
X_OFFSET: 680 [pixels]
Y_OFFSET: 1051 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 840
Y_GRB_POS: 1211
BINNING_INDEX: 1
IM_URL: sw00661869000msuni0225.fits
SUN_POSTN: 211.94d {+14h 07m 46s} -12.92d {-12d 55' 02"}
SUN_DIST: 131.75 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 39.04d {+02h 36m 10s} +11.79d {+11d 47' 19"}
MOON_DIST: 41.42 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.32,-26.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 74.31,-29.14 [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: Tue 27 Oct 15 22:53:11 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 661869, Seg_Num: 0
POINT_RA: 76.248d {+05h 05m 00s} (J2000)
POINT_DEC: -6.446d {-06d 26' 43"} (J2000)
ROLL: 113.757d
IMG_START_DATE: 17322 TJD; 300 DOY; 15/10/27
IMG_START_TIME: 81850.17 SOD {22:44:10.17} UT, 209.5 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 467678665
X_OFFSET: 680 [pixels]
Y_OFFSET: 1051 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 840
Y_GRB_POS: 1211
BINNING_INDEX: 1
IM_URL: sw00661869000msuni0225.fits
SUN_POSTN: 211.94d {+14h 07m 46s} -12.92d {-12d 55' 02"}
SUN_DIST: 131.75 [deg] Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN: 39.04d {+02h 36m 11s} +11.79d {+11d 47' 21"}
MOON_DIST: 41.41 [deg]
MOON_ILLUM: 100 [%]
GAL_COORDS: 206.32,-26.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 74.31,-29.14 [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: All 4 attachments are included.
- GCN Circular #18499
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. D'Ai (INAF-IASFPA),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
A. Maselli (INAF-IASFPA), K. L. Page (U Leicester),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and
R. L. C. Starling (U Leicester) report on behalf of the Swift Team:
At 22:40:40 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 151027B (trigger=661869). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 76.238, -6.427, which is
RA(J2000) = 05h 04m 57s
Dec(J2000) = -06d 25' 35"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a peak
with a duration of about 50 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~40 sec after the trigger.
The XRT began observing the field at 22:44:04.0 UT, 203.4 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 76.21944, -6.45010 which
is equivalent to:
RA(J2000) = 05h 04m 52.67s
Dec(J2000) = -06d 27' 00.4"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 106 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. We cannot determine whether the source is
fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 9.43
x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 5.37e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 209 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.25.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta 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 Circular #18501
Daniele Malesani (DARK/NBI), Nial R. Tanvir (Univ. Leicester), Dong Xu
(NAOC/CAS), Jussi Harmanen (NOT and Univ. Turku), Thomas Reynolds (NOT
and Turku Univ.), and Pere Blay Serrano (IAC/NOT), report on behalf of a
larger collaboration:
We observed the field of the #1000 Swift GRB 151027B (Ukwatta et al.,
GCN 18499) with the Nordic Optical Telescope equipped with the StanCam
imager. Observations started on 2015 Oct 27.988 UT (1.04 hr after the
GRB trigger), as soon as the field was observable from La Palma.
In our first 5-minute image taken in the R band, we detect a single
source consistent with the XRT position (Ukwatta et al., GCN 18499), at
coordinates (J2000):
RA = 05:04:52.69
Dec = -06:27:00.8
with an uncertainty of 0.5".
Calibrating the image against nearby USNO stars, we measure for this
object R = 18.44 +- 0.05 (Vega). While we have not yet any variability
information, the positional consistency with the XRT error circle and
the lack of any object in the DSS at this location suggest that this is
the optical afterglow of GRB 151027B.
- GCN Circular #18504
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1168 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 151027B, 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 = 76.21941, -6.45016 which is equivalent
to:
RA (J2000): 05h 04m 52.66s
Dec (J2000): -06d 27' 00.6"
with an uncertainty of 1.8 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 #18505
D. Xu (NAOC/CAS), N. R. Tanvir (U. Leicester), D. Malesani, J. Fynbo (DARK) report:
We observed the optical afterglow of GRB 151027B (Ukwatta et al. GCN 18499, Malesani et al. GCN 18501) with the VLT X-shooter spectrograph covering a spectral range 3400A to 18000A. Observations began at 2015 Oct 28 03:50 UT, approximately 5h09m post-burst.
The spectrum shows a clear continuum in the red, with a strong break corresponding to Ly-alpha at a redshift of z=4.063. This is supported by detection of absorption lines of Si II 1259/1260, Si II* 1265, CII 1335, CII* 1336, OI 1302, SiII 1304, S IV 1394/1403, CIV 1548/1551, FeII 1608 and Al II 1671 at that redshift. We therefore propose this as the redshift of the 1000th Swift GRB.
We thank the staff at Paranal, particularly T. Rivinius, for their support in obtaining these observations.
- GCN Circular #18506
D. Xu (NAOC/CAS), N. R. Tanvir (U. Leicester), D. Malesani, J. P. U.
Fynbo (DARK) report on behalf of a larger collaboration:
We observed the optical afterglow of GRB 151027B (Ukwatta et al. GCN
18499, Malesani et al. GCN 18501) with the VLT X-shooter spectrograph
covering a spectral range 3400A to 18000A. Observations began at 2015
Oct 28 03:50 UT, approximately 5h09m post-burst.
The spectrum shows a clear continuum in the red, with a strong break
corresponding to Ly-alpha at a redshift of z=4.063. This is supported
by detection of absorption lines corresponding to Si II 1259/1260, Si
II* 1265, CII 1335, CII* 1336, OI 1302, SiII 1304, S IV 1394/1403, CIV
1548/1551 and Al II 1671 at that redshift. We therefore propose this as
the redshift of the GRB.
We thank the staff at Paranal, particularly T. Rivinius and I. Condor,
for their support in obtaining these observations.
- GCN Circular #18507
P. Wiseman, J. Greiner (both MPE Garching) report on behalf of the GROND
team:
We observed the field of GRB 151027B (Swift trigger 661869; (Ukwatta et
al., GCN 18499) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).
Observations started at 06:24 UT on 28/10/2015, 7 hrs 45 mins after the
GRB trigger, and are continuing. They were performed at an average seeing
of 0.9" and at an average airmass of 1.1.
We found a single point source within the enhanced 1.8" Swift-XRT error
circle reported by Evans et al. (GCN 18504), common with that reported by
Malesani et al. (GCN 18501) and Xu et al. (GCN 18505).
Based on 6.6 min of total exposures in g'r'i'z'JHK at a mid time of
06:33:39 UT, we estimate preliminary magnitudes (all in AB system) of
g' > 22.4 mag,
r' = 20.8 +/- 0.08 mag,
i' = 20.1 +/- 0.07 mag,
z' = 20.1 +/- 0.07 mag,
J = 20.1 +/- 0.4 mag,
H = 19.1 +/- 0.3 mag, and
K > 18.3 mag.
A clear g'-band drop out in the SED leads to a photo-z of 4.3 + 0.3,-0.2,
consistent with the redshift derived from the X-shooter spectrum (Xu et
al., GCN 18505). The source appears to be fading relative to the NOT
report (Malesani et al., GCN 18501), and has continued to do so during our
observations.
Given magnitudes are calibrated against GROND zeropoints (g'r'i'z') as
well as 2MASS field stars (JHK) and are not corrected for the expected
Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.2
mag in the direction of the burst (Schlegel et al. 1998).
- GCN Circular #18509
V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA),
L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester) and T.N. Ukwatta report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 151027B (Ukwatta et al. GCN
Circ. 18499), from 191 s to 32.5 ks after the BAT trigger. The data
comprise 61 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 18504).
The light curve can be modelled with an initial power-law decay with an
index of alpha=5.7 (+/-0.6), followed by a break at T+332 s to an alpha
of 0.66 (+0.05, -0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.81 (+0.14, -0.13). The
best-fitting absorption column is 4.1 (+2.5, -2.2) x 10^22 cm^-2, at a
redshift of 4.063, in addition to the Galactic value of 9.4 x 10^20
cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum is 3.8 x
10^-11 (4.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 9.4 x 10^20 cm^-2
Intrinsic column: 4.1 (+2.5, -2.2) x 10^22 cm^-2 at z=4.063
Photon index: 1.81 (+0.14, -0.13)
If the light curve continues to decay with a power-law decay index of
0.66, the count rate at T+24 hours will be 0.026 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.9 x
10^-13 (1.2 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00661869.
This circular is an official product of the Swift-XRT team.
- GCN Circular #18511
D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov,
P.Balanutsa, A.Kuznetsov, D.Kuvshinov, D. Vlasenko, E.Popova
Lomonosov Moscow State University, Sternberg Astronomical Institute
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
V.Krushinski, I.Zalozhnih
Ural Federal University, Kourovka
Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)
Two MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in SAAO and IAC was pointed to the GRB151027B (Ukwatta et. al GCN
18499) 25 sec after notice time and 156 sec after trigger time at
2015-10-27 22:43:19 UT. On our first (30s exposure) set we haven`t found
optical transient (Malesani et. al. GCN 18501, Xu et. al. GCN 18505,
Wiseman et. al GCN 18507) within SWIFT error-box. The 2-sigma upper limit
has been about 17.7 mag. The observations were significantly complicate
the closest distance to the Moon (~ 35 d). The Moon background light is
picked up the sky background on our cameras more than 10 times. Therefore,
we could not get deep enough image. Nevertheless, we detect OT on a
several coadd images in consequent time in SAAO.
The first time we see OT 475 seconds after the trigger with magnitude ~
18.9. OT had a slight brightening 1736 seconds after the trigger to 18.5
mag.
The preliminary photometry available at table below.
Table 1. GRB151027B MASTER-SAAO Early photometry.
T-Ts T-Tm Exptime Mag.(P/+P\) Coadd
159 174 2 x 30 >17.7 1
201 221 2 x 40 >18.0 1
252 277 2 x 50 >18.3 1
313 343 2 x 60 >18.3 1
384 424 2 x 80 >18.4 1
159 311 2 x 260 >19.0 5
475 842 2 x 690 18.9 5
1235 1736 2 x 900 18.5 5
2264 3280 2 x 1800 18.9 10
3499 4515 2 x 1800 19.1 10
T - is trigger time, Ts - exposure start time, Tm - exposure middle time.
We see OT in separate polarizations on s/n~5 confidence lewel. Table 1
shows the averaged data from two mutually perpendicular polarization.
The message may be cited.
- GCN Circular #18512
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), Willia=
m H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (UCB), J. Xavier Proc=
haska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora=
Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=EF=
=BF=BD A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=EF=BF=BDs Gonz=EF=BF=
=BDlez (UNAM), Carlos Rom=EF=BF=BDn-Z=EF=BF=BD=EF=BF=BDiga (UNAM), Neil G=
ehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou =
(ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 151027B (Ukwatta et al., GCN 18499) with the=
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on th=
e 1.5m Harold Johnson Telescope at the Observatorio Astron=EF=BF=BDmico N=
acional on Sierra San Pedro M=EF=BF=BDrtir from 2015/10 28.26 to 2015/10 =
28.51 UTC (7.46 to 13.55 hours after the BAT trigger), obtaining a total =
of 3.51 hours exposure in the r, i, and z bands.
We detect a source at 05:04:52.69 -06:27:00.8 (J2000, +/-0.05), within th=
e Swift-XRT error circle. In comparison with the USNO-B1 and 2MASS catalo=
gs, we obtain the following detections:
r = 20.83 +/- 0.05
i = 20.18 +/- 0.04
z = 19.49 +/- 0.21
These magnitudes are in the AB system and are not corrected for Galactic =
extinction in the direction of the GRB.
This source coincides with the source reported by Malesani et al. (GCN 18=
501), Xu et al. (GCN 18505), Wiseman et al. (GCN 18507), and Buckley et a=
l. (GCN 18511). The source appears to have faded since these earlier obse=
rvations and furthermore fades by about 0.5 mag in i over the course of o=
ur observations.
We thank the staff of the Observatorio Astron=EF=BF=BDmico Nacional in Sa=
n Pedro M=EF=BF=BDrtir.
- GCN Circular #18514
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 151027B (trigger #661869)
(Ukwatta, et al., GCN Circ. 18499). The BAT ground-calculated position is
RA, Dec = 76.188, -6.428 deg which is
RA(J2000) = 05h 04m 45.0s
Dec(J2000) = -06d 25' 40.2"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 17%.
The mask-weighted light curve shows a complex structure with several
overlapping peaks that starts at ~T0 and ends at ~T+100 s. T90 (15-350 keV)
is 80.00 +- 35.78 sec (estimated error including systematics).
The time-averaged spectrum from T+1.00 to T+97.00 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.83 +- 0.27. The fluence in the 15-150 keV band is 1.5 +- 0.3 x 10^-6 erg/cm2.
The 1-s peak photon flux is unconstrained due to the weakness of the burst.
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/661869/BA/
- GCN Circular #18517
A. A. Breeveld (UCL-MSSL) and T. N. Ukwatta (LANL) report on behalf of
the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 151027B
210 s after the BAT trigger (Ukwatta et al., GCN Circ. 18499).
No optical afterglow consistent with the XRT position (Osborne et al.
GCN Circ. 18504) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding
chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 210 359 147 >20.0
white 210 4545 344 >20.5
v 366 4956 216 >18.8
b 4141 5737 354 >20.6
u 3935 5571 393 >20.4
w1 415 5366 397 >20.4
m2 4961 5161 197 >19.1
w2 4551 4751 197 >19.9
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.25 in the direction of the
burst (Schlegel et al. 1998).
- GCN Circular #18520
S. Dichiara (U. Ferrara, ICRANet), D. Kopac (U. Ljubljana), C. Guidorzi
(U. Ferrara), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of
a larger collaboration report:
The 2-m Faulkes Telescope North in Hawaii began observing Swift
GRB 151027B (Ukwatta et al., GCN 18499) on October 28, 12:18:25 UT, i.e.,
~ 13.6 hours after the burst trigger, with the r' and i' filters.
Although we did not detect the optical counterpart (Malesani et al.,
GCN 18501; Xu et al., GCN 18505; Wiseman et al., GCN 18507;
Buckley et al., GCN 18511; Watson et al., GCN 18512) in the r'
filter (R > 20.3), the source is detected in the i' filter with
I = 19.6 +/- 0.3 mag at a mid time of 13.9 hours post burst
(total exposure in i' of 600 s).
The magnitude is calibrated against nearby USNO-B1 stars.
- GCN Circular #18529
A. A. Breeveld (UCL-MSSL) and T. N. Ukwatta (LANL) report on behalf of
the Swift/UVOT team:
In Swift/UVOT followup observations of GRB 151027B (Ukwatta et al., GCN=20
Circ. 18499) a source is found in the summed up V filter exposures at a=20
position consistent with the XRT (Osborne et al., GCN Circ. 18504) and=20
the optical/NIR counterparts reported by Malesani et al. GCN Circ.=20
18501, Xu et al. GCN Circ. 18505, Wiseman and Greiner GCN Circ. 18507,=20
Buckley et al. GCN Circ. 18511, Watson et al. GCN Circ. 18512, and=20
Dichiara et al. GCN Circ. 18520.
A preliminary detection using the UVOT photometric system (Breeveld et=20
al. 2011, AIP Conf. Proc. 1358, 373) for V data taken in the first and=20
second segment is:
Filter T_start(s) T_stop(s) Exp(s) Mag
v 191 28529 1986 20.8 =B1 0.3
The magnitudes in the table are not corrected for the strong Galactic
extinction due to the reddening of E(B-V) =3D 0.25 in the direction of the
burst (Schlegel et al. 1998).
- GCN Circular #18543
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia=
m H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (UCB), J. Xavier Proch=
aska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora =
Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 =
A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Ca=
rlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC=
), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 151027B (Ukwatta, et al., GCN 18499) with th=
e Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on t=
he 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacion=
al on Sierra San Pedro M=E1rtir from 2015/10 31.23 to 2015/10 31.52 UTC (=
78.85 to 85.85 hours after the BAT trigger), obtaining a total of 5.20 ho=
urs exposure in the r, i, and z bands.
We no longer detect the optical afterglow (Malesani et al., GCN 18501). =
In comparison with the USNO-B1 and 2MASS catalogs, we obtain the followin=
g upper limits (3-sigma):
r > 23.45
i > 23.39
z > 18.57
These magnitudes are in the AB system and are not corrected for Galactic =
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
- GCN Circular #18548
J. Greiner (MPE), M. Wieringa (CSIRO), P. Wiseman (MPE) report for a
larger consortium:
We observed the field of GRB 151027B (Swift trigger 661869; Ukwatta et
al., GCN 18499) simultaneously at 5.5 and 9 GHz with the Australia
Telescope Compact Array (ATCA), beginning at October 30.54 UT for 3.3 hrs.
At a mean frequency of 9 GHz (with 2 GHz bandwidth) we detect a source
at ~67+/-10 microJy at the position of the optical afterglow (Malesani
et al., GCN 18501; Wiseman et al., GCN 18507). At the redshift of z=4.063
(Xu et al., GCN 18506) this is among the most luminous GRB radio afterglows.
We are grateful to P. Edwards for scheduling this observation.
- 1606.01956 from 8 Jun 16
Amy Lien et al.: The Third Swift Burst Alert Telescope Gamma-Ray Burst Catalog
To date, the Burst Alert Telescope (BAT) onboard Swift has detected ~ 1000 gamma-ray bursts (GRBs), of which ~ 360 GRBs have redshift
measurements, ranging from z = 0.03 to z = 9.38. We present the analyses of the BAT-detected GRBs for the past ~ 11 years up through
GRB151027B. We report summaries of both the temporal and spectral analyses of the GRB characteristics using event data (i.e., data for each
photon within approximately 250 s before and 950 s after the BAT trigger time), and discuss the instrumental sensitivity and selection effects
of GRB detections. We also explore the GRB properties with redshift when possible. The result summaries and data products are available at this
http URL In addition, we perform searches for GRB emissions before or after the event data using the BAT survey data. We estimate the false
detection rate to be only one false detection in this sample. There are 15 ultra-long GRBs (~ 2% of the BAT GRBs) in this search with confirmed
emission beyond ~ 1000 s of event data, and only two GRBs (GRB100316D and GRB101024A) with detections in the survey data prior to the starting
of event data.
Previous IAU Circulars 