Gamma-ray Burst 170311A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:09:28 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     741965,   Seg_Num: 0
GRB_RA:          280.563d {+18h 42m 15s} (J2000),
                 280.838d {+18h 43m 21s} (current),
                 279.764d {+18h 39m 03s} (1950)
GRB_DEC:         -30.063d {-30d 03' 45"} (J2000),
                 -30.045d {-30d 02' 41"} (current),
                 -30.112d {-30d 06' 42"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       11244 [cnts]    Image_Peak=278 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   298     E_range: 25-100 keV
BKG_INTEN:       98386 [cnts]
BKG_TIME:        29269.26 SOD {08:07:49.26} UT
BKG_DUR:         40 [sec]
GRB_DATE:        17823 TJD;    70 DOY;   17/03/11
GRB_TIME:        29322.95 SOD {08:08:42.95} UT
GRB_PHI:          42.31 [deg]
GRB_THETA:        26.85 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.67 [sigma]
IMAGE_SIGNIF:    7.33 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  -3  +0  +1 -30  +0 
SUN_POSTN:       351.68d {+23h 26m 43s}   -3.59d {-03d 35' 17"}
SUN_DIST:         71.65 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.42d {+10h 29m 41s}   +9.78d {+09d 46' 53"}
MOON_DIST:       123.70 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.84,-11.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      279.20, -6.96 [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 = 347.17,-0.07 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:10:34 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.594d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.063d {-30d 03' 45"} (J2000)
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29427.99 SOD {08:10:27.99} UT,   105.0 [sec] since BAT Trigger Time
COUNTS:          1    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        0    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:12:34 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     741965,   Seg_Num: 0
GRB_RA:          280.563d {+18h 42m 15s} (J2000),
                 280.838d {+18h 43m 21s} (current),
                 279.764d {+18h 39m 03s} (1950)
GRB_DEC:         -30.063d {-30d 03' 45"} (J2000),
                 -30.045d {-30d 02' 41"} (current),
                 -30.112d {-30d 06' 42"} (1950)
GRB_DATE:        17823 TJD;    70 DOY;   17/03/11
GRB_TIME:        29322.95 SOD {08:08:42.95} UT
TRIGGER_INDEX:   298
GRB_PHI:          42.31 [deg]
GRB_THETA:        26.85 [deg]
DELTA_TIME:      71.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.67 [sigma]
IMAGE_SIGNIF:    7.33 [sigma]
LC_URL:          sw00741965000msb.lc
SUN_POSTN:       351.68d {+23h 26m 44s}   -3.59d {-03d 35' 14"}
SUN_DIST:         71.65 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.45d {+10h 29m 48s}   +9.77d {+09d 46' 25"}
MOON_DIST:       123.67 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.84,-11.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      279.20, -6.96 [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 = 347.17,-0.07 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:14:22 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     741965,   Seg_Num: 0
GRB_RA:          280.5893d {+18h 42m 21.43s} (J2000),
                 280.8639d {+18h 43m 27.34s} (current),
                 279.7901d {+18h 39m 09.63s} (1950)
GRB_DEC:         -30.0454d {-30d 02' 43.4"} (J2000),
                 -30.0276d {-30d 01' 39.3"} (current),
                 -30.0947d {-30d 05' 40.7"} (1950)
GRB_ERROR:       3.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29456.00 SOD {08:10:56.00} UT,   133.0 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       351.68d {+23h 26m 44s}   -3.59d {-03d 35' 12"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.47d {+10h 29m 52s}   +9.77d {+09d 46' 08"}
MOON_DIST:       123.68 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.86,-11.41 [deg] galactic lon,lat of the burst
ECL_COORDS:      279.22, -6.94 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
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 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:15:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.594d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.063d {-30d 03' 44"} (J2000)
POINT_ROLL:      83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29432.46 SOD {08:10:32.46} UT,   109.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.026
N_STARS:         190
X_OFFSET:        288 [pixels]
Y_OFFSET:        643 [pixels]
X_MAX:           1247 [pixels]
Y_MAX:           1602 [pixels]
DET_THRESH:      21
PHOTO_THRESH:    12
SL_URL:          sw00741965000msufc0109.fits
SUN_POSTN:       351.68d {+23h 26m 44s}   -3.59d {-03d 35' 12"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.47d {+10h 29m 54s}   +9.77d {+09d 46' 00"}
MOON_DIST:       123.68 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.22, -6.96 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:15:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.594d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.063d {-30d 03' 44"} (J2000)
POINT_ROLL:      83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29432.46 SOD {08:10:32.46} UT,   109.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.026
N_STARS:         190
X_OFFSET:        288 [pixels]
Y_OFFSET:        643 [pixels]
X_MAX:           1247 [pixels]
Y_MAX:           1602 [pixels]
DET_THRESH:      21
PHOTO_THRESH:    12
SL_URL:          sw00741965000msufc0109.fits
SUN_POSTN:       351.68d {+23h 26m 44s}   -3.59d {-03d 35' 11"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.48d {+10h 29m 55s}   +9.77d {+09d 45' 55"}
MOON_DIST:       123.67 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.22, -6.96 [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:     Sat 11 Mar 17 08:17:00 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.594d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.063d {-30d 03' 44"} (J2000)
ROLL:            83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29432.46 SOD {08:10:32.46} UT,   109.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     510912651
X_OFFSET:        607 [pixels]
Y_OFFSET:        962 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       767
Y_GRB_POS:       1122
BINNING_INDEX:   1
IM_URL:          sw00741965000msuni0128.fits
SUN_POSTN:       351.69d {+23h 26m 45s}   -3.59d {-03d 35' 10"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.49d {+10h 29m 57s}   +9.76d {+09d 45' 44"}
MOON_DIST:       123.66 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.22, -6.96 [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:     Sat 11 Mar 17 08:17:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.594d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.063d {-30d 03' 44"} (J2000)
ROLL:            83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29432.46 SOD {08:10:32.46} UT,   109.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     510912651
X_OFFSET:        607 [pixels]
Y_OFFSET:        962 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       767
Y_GRB_POS:       1122
BINNING_INDEX:   1
IM_URL:          sw00741965000msuni0128.fits
SUN_POSTN:       351.69d {+23h 26m 45s}   -3.59d {-03d 35' 10"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.49d {+10h 29m 58s}   +9.76d {+09d 45' 41"}
MOON_DIST:       123.66 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.22, -6.96 [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:     Sat 11 Mar 17 08:22:26 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.062d {-30d 03' 41"} (J2000)
POINT_ROLL:      83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29591.86 SOD {08:13:11.86} UT,   268.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.865
N_STARS:         190
X_OFFSET:        48 [pixels]
Y_OFFSET:        403 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1842 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00741965000msufc0268.fits
SUN_POSTN:       351.69d {+23h 26m 45s}   -3.58d {-03d 35' 05"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.54d {+10h 30m 09s}   +9.75d {+09d 44' 53"}
MOON_DIST:       123.61 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:22:51 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.062d {-30d 03' 41"} (J2000)
POINT_ROLL:      83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29591.86 SOD {08:13:11.86} UT,   268.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.865
N_STARS:         190
X_OFFSET:        48 [pixels]
Y_OFFSET:        403 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1842 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00741965000msufc0268.fits
SUN_POSTN:       351.69d {+23h 26m 45s}   -3.58d {-03d 35' 04"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.54d {+10h 30m 10s}   +9.75d {+09d 44' 50"}
MOON_DIST:       123.61 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [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:     Sat 11 Mar 17 08:23:03 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     741965,   Seg_Num: 0
GRB_RA:          280.5894d {+18h 42m 21.45s} (J2000),
                 280.8640d {+18h 43m 27.36s} (current),
                 279.7902d {+18h 39m 09.65s} (1950)
GRB_DEC:         -30.0457d {-30d 02' 44.5"} (J2000),
                 -30.0279d {-30d 01' 40.3"} (current),
                 -30.0950d {-30d 05' 41.8"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29456.00 SOD {08:10:56.00} UT,   133.0 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       351.69d {+23h 26m 45s}   -3.58d {-03d 35' 04"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.54d {+10h 30m 10s}   +9.75d {+09d 44' 48"}
MOON_DIST:       123.60 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.86,-11.41 [deg] galactic lon,lat of the burst
ECL_COORDS:      279.22, -6.94 [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 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:23:54 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.062d {-30d 03' 41"} (J2000)
ROLL:            83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29591.86 SOD {08:13:11.86} UT,   268.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     510912810
X_OFFSET:        607 [pixels]
Y_OFFSET:        962 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       767
Y_GRB_POS:       1122
BINNING_INDEX:   1
IM_URL:          sw00741965000msuni0287.fits
SUN_POSTN:       351.69d {+23h 26m 46s}   -3.58d {-03d 35' 03"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.55d {+10h 30m 12s}   +9.74d {+09d 44' 40"}
MOON_DIST:       123.60 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [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:     Sat 11 Mar 17 08:24:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.062d {-30d 03' 41"} (J2000)
ROLL:            83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  29591.86 SOD {08:13:11.86} UT,   268.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     510912810
X_OFFSET:        607 [pixels]
Y_OFFSET:        962 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       767
Y_GRB_POS:       1122
BINNING_INDEX:   1
IM_URL:          sw00741965000msuni0287.fits
SUN_POSTN:       351.69d {+23h 26m 46s}   -3.58d {-03d 35' 03"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.55d {+10h 30m 13s}   +9.74d {+09d 44' 37"}
MOON_DIST:       123.60 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [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 Circular #20846
J. R. Cummings (NASA/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:
At 08:08:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170311A (trigger=741965). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 280.563, -30.063 which is
```
   RA(J2000) = 18h 42m 15s
   Dec(J2000) = -30d 03' 45"
```
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 15 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 08:10:28.0 UT, 105.1 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 280.5893, -30.0458 which is equivalent to:
```
   RA(J2000)  = 18h 42m 21.43s
   Dec(J2000) = -30d 02' 44.8"
```
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 102 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.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.30 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 109 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. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.16.
Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). 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:     Sat 11 Mar 17 08:30:07 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.061d {-30d 03' 40"} (J2000)
POINT_ROLL:      83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  30197.06 SOD {08:23:17.06} UT,   874.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.877
N_STARS:         190
X_OFFSET:        48 [pixels]
Y_OFFSET:        403 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1842 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw00741965000msufc0874.fits
SUN_POSTN:       351.69d {+23h 26m 47s}   -3.58d {-03d 34' 57"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.61d {+10h 30m 26s}   +9.73d {+09d 43' 42"}
MOON_DIST:       123.54 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 11 Mar 17 08:30:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.061d {-30d 03' 40"} (J2000)
POINT_ROLL:      83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  30197.06 SOD {08:23:17.06} UT,   874.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.877
N_STARS:         190
X_OFFSET:        48 [pixels]
Y_OFFSET:        403 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1842 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw00741965000msufc0874.fits
SUN_POSTN:       351.69d {+23h 26m 47s}   -3.58d {-03d 34' 57"}
SUN_DIST:         71.63 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.61d {+10h 30m 27s}   +9.73d {+09d 43' 38"}
MOON_DIST:       123.54 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [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:     Sat 11 Mar 17 08:32:44 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.061d {-30d 03' 40"} (J2000)
ROLL:            83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  30197.06 SOD {08:23:17.06} UT,   874.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     510913415
X_OFFSET:        607 [pixels]
Y_OFFSET:        962 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       767
Y_GRB_POS:       1122
BINNING_INDEX:   1
IM_URL:          sw00741965000msuni0893.fits
SUN_POSTN:       351.70d {+23h 26m 47s}   -3.58d {-03d 34' 54"}
SUN_DIST:         71.64 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.63d {+10h 30m 31s}   +9.72d {+09d 43' 18"}
MOON_DIST:       123.52 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [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:     Sat 11 Mar 17 08:33:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     741965,   Seg_Num: 0
POINT_RA:        280.596d {+18h 42m 23s} (J2000)
POINT_DEC:       -30.061d {-30d 03' 40"} (J2000)
ROLL:            83.490d
IMG_START_DATE:  17823 TJD;    70 DOY;   17/03/11
IMG_START_TIME:  30197.06 SOD {08:23:17.06} UT,   874.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     510913415
X_OFFSET:        607 [pixels]
Y_OFFSET:        962 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       767
Y_GRB_POS:       1122
BINNING_INDEX:   1
IM_URL:          sw00741965000msuni0893.fits
SUN_POSTN:       351.70d {+23h 26m 47s}   -3.58d {-03d 34' 54"}
SUN_DIST:         71.64 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      157.63d {+10h 30m 32s}   +9.72d {+09d 43' 15"}
MOON_DIST:       123.52 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:        4.85,-11.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      279.23, -6.96 [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 Circular #20847
R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina
H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina
V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, O. Ershova Irkutsk State University
V.Yurkov, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
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
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in OAFA was pointed to the GRB170311A 18 sec after notice time and 59 sec after trigger time (Cummings et al., GCN 20846) at 2017-03-11 08:09:45 UT. On our first (10s exposure) set we haven`t found optical transient within SWIFT error-box (ra=280.562 dec=-30.0628 r=0.05). The 5-sigma upper limit has been about 16.2 mag
The observations made on zenit distance = 49 degrees, galaxy latitude b = -12 degree. The moon (98 % bright part) is 15 degrees above the horizon. The distance between moon and object is 124 The sun altitude is -30.1 degree. The object can be observed till sunrise at 2017-03-11 10:34:12
The message may be cited.
GCN Circular #20848
P. Schady and P. Wiseman (both MPE Garching) report:
We observed the field of GRB 170311A (Swift trigger 20846; Cummings et al., GCN #20846) 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 09:45 UT on 2017-03-11, 1.6 hours after the GRB trigger. They were performed at an average seeing of 1.2" and at an average airmass of 1.1.
We do not detect a source within the Swift-XRT error circle (Cummings et al., GCN #20846) down to the following 3 sigma limiting AB magnitudes:
```
g' > 23.1 mag
r' > 23.4 mag
i' > 22.7 mag
z' > 22.5 mag
J > 20.6 mag
H > 20.2 mag
K > 19.0 mag
```
The given limits are derived based on images calibrated against Pan-STARRS/2MASS field stars, and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.14 in the direction of the burst (Schlafly & Finkbeiner 2011).
GCN Circular #20850
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 2232 s of XRT Photon Counting mode data and 3 UVOT images for GRB 170311A, 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 = 280.58942, -30.04597 which is equivalent to:
```
RA (J2000): 18h 42m 21.46s
Dec (J2000): -30d 02' 45.5"
```
with an uncertainty of 1.5 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 #20851
M. H. Siegel (PSU) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170311A 110 s after the BAT trigger (Cummings et al., GCN Circ. 20846). No optical afterglow consistent with the XRT position (Cummings et al. GCN Circ. 20846) 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           110          259          147         >20.5
u_FC               269          519          246         >19.7
white              110         7074          645         >21.2
v                  600        11424         1022         >20.3
b                  525         5585          294         >20.1
u                  269         5380          537         >20.1
w1                 650         5175          279         >20.1
m2                 624        13058           82         >20.1
w2                 575         7280          313         >20.2
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.16 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #20852
A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), A. Cholden-Brown (PSU), S. J. LaPorte (PSU), K.L. Page (U. Leicester), B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and report on behalf of the Swift-XRT team: report on behalf of the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 170311A, from 108 s to 35.6 ks after the BAT trigger. The data comprise 64 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay index of alpha=1.59 (+0.16, -0.17).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.52 (+0.28, -0.26). The best-fitting absorption column is 2.2 (+1.5, -0.9) x 10^21 cm^-2, consistent with the Galactic value of 1.3 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 4.8 x 10^-11 (5.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.2 (+1.5, -0.9) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.52 (+0.28, -0.26)
```
If the light curve continues to decay with a power-law decay index of 1.59, the count rate at T+24 hours will be 6.1 x 10^-5 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.9 x 10^-15 (3.4 x 10^-15) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00741965.
This circular is an official product of the Swift-XRT team.
GCN Circular #20853
P. Wiseman and P. Schady (both MPE Garching) report:
We re-inspected the observations of GRB 170311A taken with GROND (Schady & Wiseman, GCN #20848) with respect to the enhanced XRT position (Osborne et al., GCN #20850).
There is no credible afterglow consistent with or near to this position. The upper limits remain the same as those reported in GCN #20848.
GCN Circular #20855
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170311A (trigger #741965) (Cummings, et al. GCN Circ. 20846). The BAT ground-calculated position is RA, Dec = 280.539, -30.041 deg which is
```
  RA(J2000)  =  18h 42m 09.4s
  Dec(J2000) = -30d 02' 27.1"
```
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 64%.
The mask-weighted light curve shows a complex structure with several overlapping peaks that starts at ~T-1 s and ends at ~T+6 s. T90 (15-350 keV) is 6.32 +- 0.96 sec (estimated error including systematics).
The time-averaged spectrum from T-0.92 to T+6.08 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.38 +- 0.32. The fluence in the 15-150 keV band is 2.5 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.73 sec in the 15-150 keV band is 0.8 +- 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/741965/BA/
GCN Circular #20858
D. Malesani (DARK/NBI), H. Flores (GEPI/Paris obs.), A. J. Levan (Univ. Warwick), D. Xu (NAOC/CAS), N. R. Tanvir (Univ. Leicester), and J. P. U. Fynbo (DARK/NBI), report:
We observed the field of GRB 170311A (Cummings et al., GCN 20846) with the VLT/UT2 (Kueyen), using the acquisition camera of the X-shooter spectrograph. Observations started approximately on March 11.366 UT, that is around 38 min after the GRB trigger. Imaging was carried out using the SDSS z filter.
No source is detected within or close to the UVOT-enhanced XRT position (Osborne et al., GCN 20850), down to a 3-sigma limiting magnitude z = 21 AB, calibrated against nearby stars from the Pan-STARRS catalog (Chambers et al. 2016, arXiv: 1612.05560). Our result is consistent with other reports (e.g., Wiseman & Schady, GCN 20853).
We acknowledge excellent support from the ESO observing staff at Paranal, in particular Marcelo Lopez, Joe Anderson, and George Hau. We also acknowledge the team of the Gaia-ESO survey (ESO program 197.B-1074, PI Gilmore), for generously and consistently accepting to carry out ToO observations during their allocated nights.

Back to JG's homepage

Jochen Greiner, last update: 13-Mar-2017 [Disclaimer]