Gamma-ray Burst 150120B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 20 Jan 15 07:22:24 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     627170,   Seg_Num: 0
GRB_RA:           39.294d {+02h 37m 11s} (J2000),
                  39.495d {+02h 37m 59s} (current),
                  38.629d {+02h 34m 31s} (1950)
GRB_DEC:          +8.079d {+08d 04' 43"} (J2000),
                  +8.143d {+08d 08' 36"} (current),
                  +7.862d {+07d 51' 43"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       8290 [cnts]    Image_Peak=200 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   254     E_range: 15-50 keV
BKG_INTEN:       88794 [cnts]
BKG_TIME:        26482.92 SOD {07:21:22.92} UT
BKG_DUR:         24 [sec]
GRB_DATE:        17042 TJD;    20 DOY;   15/01/20
GRB_TIME:        26515.62 SOD {07:21:55.62} UT
GRB_PHI:         146.51 [deg]
GRB_THETA:        37.19 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     7.74 [sigma]
IMAGE_SIGNIF:    7.10 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +1  -3  +0  +0 +16  +0 
SUN_POSTN:       302.08d {+20h 08m 19s}  -20.17d {-20d 10' 06"}
SUN_DIST:         99.71 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.51d {+19h 50m 03s}  -16.09d {-16d 05' 07"}
MOON_DIST:       103.69 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.72,-46.46 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       39.48, -6.92 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate 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 = 63.29,12.32 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 20 Jan 15 07:25:39 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     627170,   Seg_Num: 0
GRB_RA:           39.294d {+02h 37m 11s} (J2000),
                  39.495d {+02h 37m 59s} (current),
                  38.629d {+02h 34m 31s} (1950)
GRB_DEC:          +8.079d {+08d 04' 43"} (J2000),
                  +8.143d {+08d 08' 36"} (current),
                  +7.862d {+07d 51' 43"} (1950)
GRB_DATE:        17042 TJD;    20 DOY;   15/01/20
GRB_TIME:        26515.62 SOD {07:21:55.62} UT
TRIGGER_INDEX:   254
GRB_PHI:         146.51 [deg]
GRB_THETA:        37.19 [deg]
DELTA_TIME:      -69.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     7.74 [sigma]
IMAGE_SIGNIF:    7.10 [sigma]
LC_URL:          sw00627170000msb.lc
SUN_POSTN:       302.08d {+20h 08m 20s}  -20.17d {-20d 10' 04"}
SUN_DIST:         99.71 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.55d {+19h 50m 12s}  -16.08d {-16d 04' 47"}
MOON_DIST:       103.66 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.72,-46.46 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       39.48, -6.92 [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 a rate 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 = 63.29,12.32 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 20 Jan 15 07:29:28 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     627170,   Seg_Num: 0
GRB_RA:           39.4459d {+02h 37m 47.01s} (J2000),
                  39.6464d {+02h 38m 35.14s} (current),
                  38.7806d {+02h 35m 07.34s} (1950)
GRB_DEC:          +8.1330d {+08d 07' 58.7"} (J2000),
                  +8.1976d {+08d 11' 51.4"} (current),
                  +7.9170d {+07d 55' 01.1"} (1950)
GRB_ERROR:       5.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.26e-09 [erg/cm2/sec]
GRB_SIGNIF:      6.16 [sigma]
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26941.29 SOD {07:29:01.29} UT,   425.7 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.23 261.44 243.49
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       302.09d {+20h 08m 21s}  -20.17d {-20d 10' 02"}
SUN_DIST:         99.87 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.59d {+19h 50m 21s}  -16.07d {-16d 04' 24"}
MOON_DIST:       103.78 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.85,-46.33 [deg] galactic lon,lat of the burst
ECL_COORDS:       39.64, -6.91 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 9.59 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 .  
COMMENTS:        WARNING: The centroided position is more than 100 rows or columns from the center of the FOV.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 20 Jan 15 07:29:38 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     627170,   Seg_Num: 0
GRB_RA:           39.4459d {+02h 37m 47.0s} (J2000),
                  39.6464d {+02h 38m 35.1s} (current),
                  38.7806d {+02h 35m 07.3s} (1950)
GRB_DEC:          +8.1330d {+08d 07' 58.7"} (J2000),
                  +8.1976d {+08d 11' 51.4"} (current),
                  +7.9170d {+07d 55' 01.1"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       38 [cnts]
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26941.29 SOD {07:29:01.29} UT,   425.7 [sec] since BAT Trigger Time
CENTROID_X:      566.08,  raw= 566  [pixels]
CENTROID_Y:      296.71,  raw= 297  [pixels]
ROLL:            250.78 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -2.55
GRB_POS_XRT_Z:   614.75
IMAGE_URL:       sw00627170000msxps_rw.img
SUN_POSTN:       302.09d {+20h 08m 21s}  -20.17d {-20d 10' 02"}
SUN_DIST:         99.87 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.59d {+19h 50m 22s}  -16.07d {-16d 04' 23"}
MOON_DIST:       103.78 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.85,-46.33 [deg] galactic lon,lat of the burst
ECL_COORDS:       39.64, -6.91 [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 .  
COMMENTS:        WARNING: The centroided position is more than 100 rows or columns from the center of the FOV.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 20 Jan 15 07:29:54 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     627170,   Seg_Num: 0
GRB_RA:           39.4459d {+02h 37m 47.0s} (J2000),
                  39.6464d {+02h 38m 35.1s} (current),
                  38.7806d {+02h 35m 07.3s} (1950)
GRB_DEC:          +8.1330d {+08d 07' 58.7"} (J2000),
                  +8.1976d {+08d 11' 51.4"} (current),
                  +7.9170d {+07d 55' 01.1"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       38 [cnts]
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26941.29 SOD {07:29:01.29} UT,   425.7 [sec] since BAT Trigger Time
CENTROID_X:      566.08,  raw= 566  [pixels]
CENTROID_Y:      296.71,  raw= 297  [pixels]
ROLL:            250.78 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -2.55
GRB_POS_XRT_Z:   614.75
IMAGE_URL:       sw00627170000msxps_rw.img
SUN_POSTN:       302.09d {+20h 08m 21s}  -20.17d {-20d 10' 02"}
SUN_DIST:         99.87 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.59d {+19h 50m 22s}  -16.07d {-16d 04' 21"}
MOON_DIST:       103.77 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.85,-46.33 [deg] galactic lon,lat of the burst
ECL_COORDS:       39.64, -6.91 [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:     Tue 20 Jan 15 07:34:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.283d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.076d {+08d 04' 34"} (J2000)
POINT_ROLL:      250.780d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26947.73 SOD {07:29:07.73} UT,   432.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.403
N_STARS:         22
X_OFFSET:        384 [pixels]
Y_OFFSET:        576 [pixels]
X_MAX:           1343 [pixels]
Y_MAX:           1535 [pixels]
DET_THRESH:      25
PHOTO_THRESH:    16
SL_URL:          sw00627170000msufc0432.fits
SUN_POSTN:       302.09d {+20h 08m 22s}  -20.17d {-20d 10' 00"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.65d {+19h 50m 35s}  -16.06d {-16d 03' 51"}
MOON_DIST:       103.55 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 20 Jan 15 07:35:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.283d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.076d {+08d 04' 34"} (J2000)
POINT_ROLL:      250.780d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26947.73 SOD {07:29:07.73} UT,   432.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.403
N_STARS:         22
X_OFFSET:        384 [pixels]
Y_OFFSET:        576 [pixels]
X_MAX:           1343 [pixels]
Y_MAX:           1535 [pixels]
DET_THRESH:      25
PHOTO_THRESH:    16
SL_URL:          sw00627170000msufc0432.fits
SUN_POSTN:       302.09d {+20h 08m 22s}  -20.17d {-20d 10' 00"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.65d {+19h 50m 36s}  -16.06d {-16d 03' 49"}
MOON_DIST:       103.55 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [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 20 Jan 15 07:36:08 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.283d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.076d {+08d 04' 34"} (J2000)
ROLL:            250.780d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26947.73 SOD {07:29:07.73} UT,   432.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     443431760
X_OFFSET:        0 [pixels]
Y_OFFSET:        1461 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       0
Y_GRB_POS:       1621
BINNING_INDEX:   1
IM_URL:          sw00627170000msuni0446.fits
SUN_POSTN:       302.09d {+20h 08m 22s}  -20.17d {-20d 09' 59"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.66d {+19h 50m 38s}  -16.06d {-16d 03' 43"}
MOON_DIST:       103.54 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [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 20 Jan 15 07:36:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.283d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.076d {+08d 04' 34"} (J2000)
ROLL:            250.780d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26947.73 SOD {07:29:07.73} UT,   432.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     443431760
X_OFFSET:        0 [pixels]
Y_OFFSET:        1461 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       0
Y_GRB_POS:       1621
BINNING_INDEX:   1
IM_URL:          sw00627170000msuni0446.fits
SUN_POSTN:       302.09d {+20h 08m 22s}  -20.17d {-20d 09' 59"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.66d {+19h 50m 39s}  -16.06d {-16d 03' 41"}
MOON_DIST:       103.54 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [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:     Tue 20 Jan 15 07:39:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.282d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.078d {+08d 04' 42"} (J2000)
POINT_ROLL:      250.781d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  27378.92 SOD {07:36:18.92} UT,   863.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.093
N_STARS:         47
X_OFFSET:        0 [pixels]
Y_OFFSET:        608 [pixels]
X_MAX:           1439 [pixels]
Y_MAX:           2047 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00627170000msufc0863.fits
SUN_POSTN:       302.09d {+20h 08m 22s}  -20.17d {-20d 09' 57"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.69d {+19h 50m 46s}  -16.06d {-16d 03' 24"}
MOON_DIST:       103.51 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 20 Jan 15 07:40:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.282d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.078d {+08d 04' 42"} (J2000)
POINT_ROLL:      250.781d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  27378.92 SOD {07:36:18.92} UT,   863.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.093
N_STARS:         47
X_OFFSET:        0 [pixels]
Y_OFFSET:        608 [pixels]
X_MAX:           1439 [pixels]
Y_MAX:           2047 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00627170000msufc0863.fits
SUN_POSTN:       302.09d {+20h 08m 22s}  -20.17d {-20d 09' 57"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.70d {+19h 50m 48s}  -16.06d {-16d 03' 18"}
MOON_DIST:       103.50 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [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 20 Jan 15 07:41:17 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.282d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.078d {+08d 04' 42"} (J2000)
ROLL:            250.781d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  27378.92 SOD {07:36:18.92} UT,   863.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     443432192
X_OFFSET:        559 [pixels]
Y_OFFSET:        1167 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       719
Y_GRB_POS:       1327
BINNING_INDEX:   1
IM_URL:          sw00627170000msuni0877.fits
SUN_POSTN:       302.09d {+20h 08m 23s}  -20.17d {-20d 09' 56"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.71d {+19h 50m 51s}  -16.05d {-16d 03' 11"}
MOON_DIST:       103.49 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [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:     Tue 20 Jan 15 07:41:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     627170,   Seg_Num: 0
POINT_RA:         39.282d {+02h 37m 08s} (J2000)
POINT_DEC:        +8.078d {+08d 04' 42"} (J2000)
ROLL:            250.781d
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  27378.92 SOD {07:36:18.92} UT,   863.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     443432192
X_OFFSET:        559 [pixels]
Y_OFFSET:        1167 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       719
Y_GRB_POS:       1327
BINNING_INDEX:   1
IM_URL:          sw00627170000msuni0877.fits
SUN_POSTN:       302.09d {+20h 08m 23s}  -20.17d {-20d 09' 56"}
SUN_DIST:         99.69 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.72d {+19h 50m 52s}  -16.05d {-16d 03' 09"}
MOON_DIST:       103.48 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.70,-46.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.47, -6.92 [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:        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:     Tue 20 Jan 15 07:45:31 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     627170,   Seg_Num: 0
GRB_RA:           39.2927d {+02h 37m 10.24s} (J2000),
                  39.4931d {+02h 37m 58.35s} (current),
                  38.6277d {+02h 34m 30.64s} (1950)
GRB_DEC:          +8.0779d {+08d 04' 40.4"} (J2000),
                  +8.1427d {+08d 08' 33.5"} (current),
                  +7.8614d {+07d 51' 41.0"} (1950)
GRB_ERROR:       2.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17042 TJD;    20 DOY;   15/01/20
IMG_START_TIME:  26969.00 SOD {07:29:29.00} UT,   453.4 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       302.10d {+20h 08m 23s}  -20.17d {-20d 09' 54"}
SUN_DIST:         99.70 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      297.76d {+19h 51m 02s}  -16.05d {-16d 02' 45"}
MOON_DIST:       103.45 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      162.71,-46.47 [deg] galactic lon,lat of the burst
ECL_COORDS:       39.48, -6.92 [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:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 2.8% < P(seren) < 6.6%.

GCN Circular #17314
V. D'Elia (ASDC), L. Izzo (URoma/ICRA), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 07:21:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150120B (trigger=627170). Swift slewed to this burst after a short delay due the Earth limb constraint. The BAT on-board calculated location is RA, Dec 39.294, +8.079 which is
```
   RA(J2000) = 02h 37m 11s
   Dec(J2000) = +08d 04' 43"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 30 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 07:29:01.2 UT, 425.7 seconds after the BAT trigger. The position determined from promptly downlinked data differs significantly from the on-board position, suggesting that the XRT may have centroided on a cosmic ray; the initial XRT position notice should be treated with caution. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 39.2927, 8.0781 which is equivalent to:
```
   RA(J2000)  = 02h 37m 10.25s
   Dec(J2000) = +08d 04' 41.2"
```
with an uncertainty of 2.7 arcseconds (radius, 90% containment). This location is 5.7 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 1.16 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 432 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 none of the XRT error circle. 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 0.20.
Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). 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 #17315
D. A. Perley (Caltech) reports on behalf of a larger collaboration:
The Palomar 60-inch robotic telescope began automatic follow-up of the location of GRB 150120B (D'Elia et al., GCN 17314) starting at 07:26:07 UT on 2015-01-20.
In the first three 60-second frames (r, i, and z-bands) we detect a bright (r~18.7 mag), new source at the following location (J2000):
```
  
RA  =  02:37:09.770
dec = +08:04:40.37
```
After these three frames, the telescope received the initial XRT position notice and it executed a large slew to a new position, and this optical source was no longer in the field of view. It returned to the field with the updated XRT position notice in an image starting at 07:47:47; the GRB afterglow shows significant fading (to r~19.7 mag) in this observation since the first epoch, confirming it as the optical afterglow.
We also note that the optical position above is near, but significantly outside (7 arcsec west) of, the updated XRT position given in GCN 17314.
GCN Circular #17316
C. Guidorzi, S. Dichiara (U. Ferrara), C.G. Mundell (LJMU), A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report:
The 2-m Faulkes Telescope North began observing Swift GRB150120B (D'Elia et al. GCN 17314) on Jan 20 at 07:39:45 UT (~18 minutes after the burst trigger) with SDSS r and i filters. We clearly detect the optical candidate reported by Perley (GCN 17315), with a magnitude of r=19.21 +- 0.07 calibrated against nearby USNOB-1 (R1) stars.
GCN Circular #17320
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 5081 s of XRT Photon Counting mode data and 8 UVOT images for GRB 150120B, 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 = 39.29070, +8.07795 which is equivalent to:
```
RA (J2000): 02h 37m 9.77s
Dec (J2000): +08d 04' 40.6"
```
with an uncertainty of 1.4 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 #17325
J.A. Kennea (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. de Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), V. Mangano (PSU), M.C. Stroh (PSU) and V. D'Elia report on behalf of the Swift-XRT team:
We have analysed 9.0 ks of XRT data for GRB 150120B (D'Elia et al. GCN Circ. 17314), from 438 s to 19.9 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 17320).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.91 (+/-0.05).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.97 (+0.14, -0.15). The best-fitting absorption column is 3.2 (+0.7, -0.8) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^21 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 (5.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.2 (+0.7, -0.8) x 10^21 cm^-2
Galactic foreground: 1.2 x 10^21 cm^-2
Excess significance: 4.5 sigma
Photon index:	     1.97 (+0.14, -0.15)
```
If the light curve continues to decay with a power-law decay index of 0.91, the count rate at T+24 hours will be 6.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.6 x 10^-13 (3.8 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00627170.
This circular is an official product of the Swift-XRT team.
GCN Circular #17330
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC) N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150120B (trigger #627170) (V. D'Elia, et al., GCN Circ. 17314). The BAT ground-calculated position is RA, Dec = 39.309, 8.064 deg which is
```
  RA(J2000)  =  02h 37m 14.1s
  Dec(J2000) = +08d 03' 50.3"
```
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%.
The mask-weighted light curve shows a multi-peaked structure starts at ~ T-20 s and ends at ~ T+10 s, with the main peak at ~ T+0 s. T90 (15-350 keV) is 24.30 +- 3.39 sec (estimated error including systematics).
The time-averaged spectrum from T-17.64 to T+9.63 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.20 +- 0.25. The fluence in the 15-150 keV band is 5.4 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.58 sec in the 15-150 keV band is 1.2 +- 0.2 ph/cm2/sec. 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/627170/BA/
GCN Circular #17331
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration:
We observed the field of GRB 150120B (D'Elia et al., GCNC 17314) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2015-01-20 11:12:04 UT (~3.8 h after the burst). We could not detect the previously reported afterglow (Perley, GCNC 17315; Guidorzi et al., GCNC 17316) in all the three bands.
Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.20162    12:12:15    5760.0   >19.6  >19.6  >19.1
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #17335
D. A. Perley (Caltech) and S. B. Cenko (NASA/GSFC) report:
We obtained further observations at the position of the optical afterglow (Perley, GCN 17315) of GRB 150120B (D'Elia et al., GCN 17314) with the Palomar 60-inch robotic telescope on the night of 2015-01-21 UT. In a combined stack of five 300-second r-band exposures we no longer detect any significant emission at the location of the optical afterglow. We estimate a limiting magnitude of r>22.7 mag (3 sigma) at a mid-time of 02:32:27 UT, t=0.799 days after the GRB. Relative to our previous observations, this suggests a decay power-law slope of at least alpha>0.75.
GCN Circular #17336
P. Wiseman, J. Graham, P. Schady and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 150120B (Swift trigger 627170; D'Elia et al., GCN 17314) 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 01:25 UT on 21.01.2015, ~18hrs after the GRB trigger. They were performed at an average seeing of 1.1" and at an average airmass of 1.7.
We find a single point source within the 1.4" Swift-XRT error circle (Goad et al., GCN 17320), consistent with that reported by Perley et al. (GCN 17315), Guidorzi et al. (GCN 17316), at
```
RA (J2000.0) = 02 h 37 m 09.77 s
DEC (J2000.0) = +08d 04' 40.49"
```
with an uncertainty of 0.3" in each coordinate.
Based on 25 min of total exposures in g'r'i'z'JHK, we estimate preliminary magnitudes and 3 sigma upper limits (all in AB system) of
```
g' > 24.2
r' = 23.6 +/- 0.1 mag,
i' = 22.7 +/- 0.2 mag,
z' = 22.4 +/- 0.40 mag,
J = 20.2 +/- 0.3 mag,
H = 19.9 +/- 0.5 mag, and
K = 18.7 +/- 0.4 mag.
```
Based on these magnitudes, the best-fit SED has a break in the g' band suggesting a photometric redshift of 3.5 +/-0.5.
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)=0.17 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #17337
S. B. Pandey (ARIES Nainital India, on behalf of larger Indian GRB collaboration)
The 1.04m Sampurnanand telescope at ARIES Nainital began observations of the Swift-detected GRB 150120B (D'Elia et al., GCN 17314) starting at 13:34:44 UT on 2015-01-20. Several frames in R_c pass-band 300sec each were acquired in poor sky conditions.
In the co-added image (6x300 sec), we detect the optical afterglow candidate at R_c ~ 21.7+-0.1 mag to the location consistent with that reported by Perley et al. (GCN 17315), Guidorzi et al. (GCN 17316). The temporal power-law flux decay seems to follow an index of 0.7 at the epoch of our observations as reported by Perley & Cenko (GCN 17335). The photometry was performed in comparison to nearby USNO- B1 stars.
This massage may be cited.
GCN Circular #17338
GRB 150120B: Swift/UVOT Upper Limits
M. M. Chester (PSU) and V. D'Elia (ASDC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150120B 432 s after the BAT trigger (D'Elia et al., GCN Circ. 17314). No source consistent with the optical afterglow reported by Perley (GCN Circ. 17315) and Guidorzi et al. (GCN Circ. 17316) 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           432          582          147         >19.9
white              432         1014          295         >20.5
white             7279         7479          197         >20.7
v                 6254        19560         1278         >20.1
b                 7074        25878          979         >20.9
u                 6869        25353         1999         >21.0
w1                 639         2670          214         >19.6
w1                6664        24440         2164         >21.0
m2                6459        20294         1996         >21.0
w2                1885         3036          124         >19.5
w2                7484        18646         1082         >20.8
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.20 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #17339
L. P. Xin, X. F. Wang, J. Y. Wei, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han and C. Wu on behalf of EAFON report:
We began to observe GRB 150120B (D'Elia et al., GCN 17314) with Xinglong 0.8-m TNT telescope at 2015-01-20, 10:56:50 (UT), about 3.58 hours after the burst.
In the 15*300sec coadded R-bamd image, the optical counterpart (D. A. Perley GCN 17315; Guidorzi et al., GCN 17316; Wiseman et al., 17336; Pandey GCN 17337) was detected with a brightness of R=21.3+/-0.2 mag at the mid-time of 4.2 hours after the burst, calibrated by the nearby USNO B1.0 R2 mag.
The message may be cited.
GCN Circular #17340
C. Guidorzi, S. Dichiara (U. Ferrara), C.G. Mundell (LJMU), A. Gomboc (U. Ljubljana) on behalf of a large collaboration report:
The 2-m Faulkes Telescope North observed Swift GRB150120B (D'Elia et al. GCN 17314; Perley GCN 17315) from 18 to 100 minutes since the burst trigger time with SDSS r and i filters. Both light curves are fitted with a power-law with a decay index alpha=0.8 +- 0.1. A comparison with the observations at later times (Perley GCN 17335; Wiseman et al. GCN 17336; Pandey GCN 17337; Xin et al. GCN 17339) suggests that a steepening of the decay must have occurred between ~2e4 and ~6e4 s.
GCN Circular #17343
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 (ORAU/GSFC), 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 150120B (D'Elia, et al., GCN 17314) 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 2015/01 21.09 to 2015/01 21.29 UTC (18.73 to 23.64 hours after the BAT trigger), obtaining a total of 3.91 hours exposure in the r, i, and z bands.
For a source coincident with the GROND optical transient (Wiseman et al., GCN 17336), in comparison with 2MASS, we obtain the following detections and upper limit (3-sigma):
```
  r = 23.4 +/- 0.2
  i = 22.6 +/- 0.1
  z > 20.72
```
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 #17347
E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150120B (D'Elia et al., GCN 17314) with AZT-33IK telescope of Sayan observatory (Mondy) Jan., 20 starting on (UT) 11:42:02. We obtained 65 images in R-filter of 120 s exposure. In two combined images within enhanced Swift-XRT error circle (Goad et al., GCN 17320) we clearly detect optical afterglow (Perley et al. GCN 17315, Guidorzi et al. GCN 17316). Photometry of the afterglow is following
```
Date       UT start   t-T0     Filter   Exp.    OT    Err.
                       (mid, days)       (s)

2015-01-20 11:42:02   0.20149  R        30*120  21.25 0.22
2015-01-20 12:42:04   0.24348  R        30*120  21.43 0.25
```
Photometry is based on nearby USNO B1.0 (R2) stars:
```
USNO-B1.0_id R
0980-0031064 15.57
0980-0031070 14.16
0980-0031080 16.35
0980-0031095 15.41
```
GCN Circular #17366
E. Mazaeva (IKI), S. Schmalz (AIP), N. Tungalag (Research Center of Astronomy and Geophysics MAS), A. Volnova (IKI), I.Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150120B (D'Elia et al., GCN 17314) with ORI-40 telescope of Khureltogot observatory on Jan., 20 starting on (UT) 10:52:51. We obtained 90 unfiltered images of 60 s exposure. Within enhanced Swift-XRT error circle (Goad et al., GCN 17320) we clearly detect optical afterglow (Perley et al. GCN 17315, Guidorzi et al. GCN 17316) in a combined image. Photometry of the afterglow is following
```
Date        UT start  t-T0       Filter  Exp.   OT    OT_err
                       (mid, days)        (s)

2015-01-20  10:52:51  0.18068    none    90*60  20.75 0.20
```
The photometry is based on R magnitudes of nearby USNO-B1.0 stars
```
USNO-B1_id   R2
0981-0032639 16.04
0981-0032644 17.10
```
GCN Circular #17651
J. Mao, J. Zhang, and J.-M. Bai (YNAO) report:
We observed the field of GRB 150120B (D'Elia et al., GCN 17314) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatory. Observations began from UT 13:42:43.5 20th, Jan., 2015 (about 6.3 hours after the trigger). We clearly detected the optical counterpart with brightness of R=22.1+/-0.1 mag.
J. Mao apologizes for this very late GCN circular submission.

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