Gamma-ray Burst 120308A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:14:19 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     517234,   Seg_Num: 0
GRB_RA:          219.078d {+14h 36m 19s} (J2000),
                 218.999d {+14h 36m 00s} (current),
                 219.417d {+14h 37m 40s} (1950)
GRB_DEC:         +79.703d {+79d 42' 12"} (J2000),
                 +79.651d {+79d 39' 03"} (current),
                 +79.919d {+79d 55' 08"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       18503 [cnts]    Image_Peak=473 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   298     E_range: 25-100 keV
BKG_INTEN:       171251 [cnts]
BKG_TIME:        22360.03 SOD {06:12:40.03} UT
BKG_DUR:         40 [sec]
GRB_DATE:        15994 TJD;    68 DOY;   12/03/08
GRB_TIME:        22418.65 SOD {06:13:38.65} UT
GRB_PHI:         -28.68 [deg]
GRB_THETA:        19.84 [deg]
SOLN_STATUS:     0x2003
RATE_SIGNIF:     8.30 [sigma]
IMAGE_SIGNIF:    8.74 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  -1  +0  +0 +19  +0 
SUN_POSTN:       349.04d {+23h 16m 09s}   -4.71d {-04d 42' 43"}
SUN_DIST:        101.30 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.36d {+11h 01m 27s}   +0.89d {+00d 53' 20"}
MOON_DIST:        83.01 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      115.73, 71.36 [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:        There is a bright star (mag=6.26) 7.63 arcmin from this position.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 295.25,-1.40 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:15:43 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     517234,   Seg_Num: 0
GRB_RA:          219.0791d {+14h 36m 18.98s} (J2000),
                 219.0010d {+14h 36m 00.24s} (current),
                 219.4168d {+14h 37m 40.04s} (1950)
GRB_DEC:         +79.6867d {+79d 41' 12.1"} (J2000),
                 +79.6340d {+79d 38' 02.4"} (current),
                 +79.9023d {+79d 54' 08.3"} (1950)
GRB_ERROR:       5.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.17e-09 [erg/cm2/sec]
GRB_SIGNIF:      6.92 [sigma]
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22511.33 SOD {06:15:11.33} UT,   92.7 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.26 261.49 243.72
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       349.04d {+23h 16m 09s}   -4.71d {-04d 42' 42"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.38d {+11h 01m 31s}   +0.88d {+00d 53' 00"}
MOON_DIST:        83.00 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.30, 36.27 [deg] galactic lon,lat of the burst
ECL_COORDS:      115.78, 71.36 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.00 arcmin from the BAT position.  
COMMENTS:        There is a bright star (mag=6.26) 7.37 arcmin from the XRT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:15:53 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     517234,   Seg_Num: 0
GRB_RA:          219.0791d {+14h 36m 18.9s} (J2000),
                 219.0010d {+14h 36m 00.2s} (current),
                 219.4168d {+14h 37m 40.0s} (1950)
GRB_DEC:         +79.6867d {+79d 41' 12.1"} (J2000),
                 +79.6340d {+79d 38' 02.4"} (current),
                 +79.9023d {+79d 54' 08.3"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       48 [cnts]
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22511.33 SOD {06:15:11.33} UT,   92.7 [sec] since BAT Trigger Time
CENTROID_X:      303.27,  raw= 303  [pixels]
CENTROID_Y:      285.35,  raw= 285  [pixels]
ROLL:            51.12 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -29.80
GRB_POS_XRT_Z:   -0.99
IMAGE_URL:       sw00517234000msxps_rw.img
SUN_POSTN:       349.04d {+23h 16m 09s}   -4.71d {-04d 42' 42"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.38d {+11h 01m 31s}   +0.88d {+00d 52' 58"}
MOON_DIST:        83.00 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.30, 36.27 [deg] galactic lon,lat of the burst
ECL_COORDS:      115.78, 71.36 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:16:01 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     517234,   Seg_Num: 0
GRB_RA:          219.0791d {+14h 36m 18.9s} (J2000),
                 219.0010d {+14h 36m 00.2s} (current),
                 219.4168d {+14h 37m 40.0s} (1950)
GRB_DEC:         +79.6867d {+79d 41' 12.1"} (J2000),
                 +79.6340d {+79d 38' 02.4"} (current),
                 +79.9023d {+79d 54' 08.3"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       48 [cnts]
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22511.33 SOD {06:15:11.33} UT,   92.7 [sec] since BAT Trigger Time
CENTROID_X:      303.27,  raw= 303  [pixels]
CENTROID_Y:      285.35,  raw= 285  [pixels]
ROLL:            51.12 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -29.80
GRB_POS_XRT_Z:   -0.99
IMAGE_URL:       sw00517234000msxps_rw.img
SUN_POSTN:       349.04d {+23h 16m 09s}   -4.71d {-04d 42' 42"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.38d {+11h 01m 31s}   +0.88d {+00d 52' 56"}
MOON_DIST:        83.00 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.30, 36.27 [deg] galactic lon,lat of the burst
ECL_COORDS:      115.78, 71.36 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:17:32 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     517234,   Seg_Num: 0
GRB_RA:          219.078d {+14h 36m 19s} (J2000),
                 218.999d {+14h 36m 00s} (current),
                 219.417d {+14h 37m 40s} (1950)
GRB_DEC:         +79.703d {+79d 42' 12"} (J2000),
                 +79.651d {+79d 39' 03"} (current),
                 +79.919d {+79d 55' 08"} (1950)
GRB_DATE:        15994 TJD;    68 DOY;   12/03/08
GRB_TIME:        22418.65 SOD {06:13:38.65} UT
TRIGGER_INDEX:   298
GRB_PHI:         -28.68 [deg]
GRB_THETA:        19.84 [deg]
DELTA_TIME:      58.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x2003
RATE_SIGNIF:     8.30 [sigma]
IMAGE_SIGNIF:    8.74 [sigma]
LC_URL:          sw00517234000msb.lc
SUN_POSTN:       349.04d {+23h 16m 09s}   -4.71d {-04d 42' 40"}
SUN_DIST:        101.30 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.39d {+11h 01m 35s}   +0.88d {+00d 52' 36"}
MOON_DIST:        83.01 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      115.73, 71.36 [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:        There is a bright star (mag=6.26) 7.63 arcmin from this position.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 295.25,-1.40 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:23:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.038d {+14h 36m 09s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
POINT_ROLL:      51.111d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22576.11 SOD {06:16:16.11} UT,   157.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.197
N_STARS:         190
X_OFFSET:        0 [pixels]
Y_OFFSET:        0 [pixels]
X_MAX:           2047 [pixels]
Y_MAX:           2047 [pixels]
DET_THRESH:      5
PHOTO_THRESH:    2
SL_URL:          sw00517234000msufc0157.fits
SUN_POSTN:       349.04d {+23h 16m 10s}   -4.71d {-04d 42' 34"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.45d {+11h 01m 49s}   +0.85d {+00d 51' 10"}
MOON_DIST:        83.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.27 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:24:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.038d {+14h 36m 09s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
POINT_ROLL:      51.111d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22576.11 SOD {06:16:16.11} UT,   157.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.197
N_STARS:         190
X_OFFSET:        0 [pixels]
Y_OFFSET:        0 [pixels]
X_MAX:           2047 [pixels]
Y_MAX:           2047 [pixels]
DET_THRESH:      5
PHOTO_THRESH:    2
SL_URL:          sw00517234000msufc0157.fits
SUN_POSTN:       349.04d {+23h 16m 10s}   -4.71d {-04d 42' 33"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.46d {+11h 01m 50s}   +0.85d {+00d 51' 03"}
MOON_DIST:        83.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.27 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:24:56 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.038d {+14h 36m 09s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
ROLL:            51.111d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22576.11 SOD {06:16:16.11} UT,   157.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     352880184
X_OFFSET:        838 [pixels]
Y_OFFSET:        933 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       998
Y_GRB_POS:       1093
BINNING_INDEX:   1
IM_URL:          sw00517234000msuni0165.fits
SUN_POSTN:       349.04d {+23h 16m 11s}   -4.71d {-04d 42' 33"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.46d {+11h 01m 51s}   +0.85d {+00d 50' 54"}
MOON_DIST:        83.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.27 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [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).  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:25:17 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.038d {+14h 36m 09s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
ROLL:            51.111d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22576.11 SOD {06:16:16.11} UT,   157.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     352880184
X_OFFSET:        838 [pixels]
Y_OFFSET:        933 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       998
Y_GRB_POS:       1093
BINNING_INDEX:   1
IM_URL:          sw00517234000msuni0165.fits
SUN_POSTN:       349.04d {+23h 16m 11s}   -4.71d {-04d 42' 32"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.47d {+11h 01m 52s}   +0.85d {+00d 50' 49"}
MOON_DIST:        83.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.27 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [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.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN Circular #13017
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), M. M. Chester (PSU), V. D'Elia (ASDC), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 06:13:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120308A (trigger=517234). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 219.078, +79.703 which is
```
   RA(J2000) = 14h 36m 19s
   Dec(J2000) = +79d 42' 12"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a broad peak structure with a duration of about ~30 sec. The peak count rate was ~500 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 06:15:11.3 UT, 92.6 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 219.08492, 79.68629 which is equivalent to:
```
   RA(J2000)  = 14h 36m 20.38s
   Dec(J2000) = +79d 41' 10.6"
```
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 60 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 2.89 x 10^20 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 1.17e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 250 seconds with the U filter starting 157 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 19.2 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 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03.
Burst Advocate for this burst is W. H. Baumgartner (wayne 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:     Thu 08 Mar 12 06:32:26 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.040d {+14h 36m 10s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
POINT_ROLL:      51.112d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  23275.97 SOD {06:27:55.97} UT,   857.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.254
N_STARS:         140
X_OFFSET:        278 [pixels]
Y_OFFSET:        373 [pixels]
X_MAX:           1717 [pixels]
Y_MAX:           1812 [pixels]
DET_THRESH:      5
PHOTO_THRESH:    2
SL_URL:          sw00517234000msufc0857.fits
SUN_POSTN:       349.05d {+23h 16m 12s}   -4.71d {-04d 42' 25"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.53d {+11h 02m 08s}   +0.82d {+00d 49' 12"}
MOON_DIST:        83.04 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.26 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:32:55 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.040d {+14h 36m 10s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
POINT_ROLL:      51.112d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  23275.97 SOD {06:27:55.97} UT,   857.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.254
N_STARS:         140
X_OFFSET:        278 [pixels]
Y_OFFSET:        373 [pixels]
X_MAX:           1717 [pixels]
Y_MAX:           1812 [pixels]
DET_THRESH:      5
PHOTO_THRESH:    2
SL_URL:          sw00517234000msufc0857.fits
SUN_POSTN:       349.05d {+23h 16m 12s}   -4.71d {-04d 42' 25"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.54d {+11h 02m 09s}   +0.82d {+00d 49' 05"}
MOON_DIST:        83.04 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.26 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:33:52 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     517234,   Seg_Num: 0
GRB_RA:          219.0848d {+14h 36m 20.35s} (J2000),
                 219.0067d {+14h 36m 01.60s} (current),
                 219.4227d {+14h 37m 41.44s} (1950)
GRB_DEC:         +79.6868d {+79d 41' 12.4"} (J2000),
                 +79.6341d {+79d 38' 02.8"} (current),
                 +79.9024d {+79d 54' 08.6"} (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:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  22709.00 SOD {06:18:29.00} UT,   290.3 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       349.05d {+23h 16m 12s}   -4.71d {-04d 42' 24"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.55d {+11h 02m 11s}   +0.81d {+00d 48' 52"}
MOON_DIST:        83.04 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.30, 36.27 [deg] galactic lon,lat of the burst
ECL_COORDS:      115.77, 71.36 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        There is a bright star (mag=6.26) 7.43 arcmin from the XRT position.  
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:     Thu 08 Mar 12 06:34:01 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.040d {+14h 36m 10s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
ROLL:            51.112d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  23275.97 SOD {06:27:55.97} UT,   857.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     352880883
X_OFFSET:        837 [pixels]
Y_OFFSET:        932 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       997
Y_GRB_POS:       1092
BINNING_INDEX:   1
IM_URL:          sw00517234000msuni0865.fits
SUN_POSTN:       349.05d {+23h 16m 12s}   -4.71d {-04d 42' 24"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.55d {+11h 02m 12s}   +0.81d {+00d 48' 50"}
MOON_DIST:        83.04 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.26 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [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).  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 08 Mar 12 06:34:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     517234,   Seg_Num: 0
POINT_RA:        219.040d {+14h 36m 10s} (J2000)
POINT_DEC:       +79.694d {+79d 41' 37"} (J2000)
ROLL:            51.112d
IMG_START_DATE:  15994 TJD;    68 DOY;   12/03/08
IMG_START_TIME:  23275.97 SOD {06:27:55.97} UT,   857.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     352880883
X_OFFSET:        837 [pixels]
Y_OFFSET:        932 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       997
Y_GRB_POS:       1092
BINNING_INDEX:   1
IM_URL:          sw00517234000msuni0865.fits
SUN_POSTN:       349.05d {+23h 16m 12s}   -4.71d {-04d 42' 24"}
SUN_DIST:        101.31 [deg]   Sun_angle= 8.7 [hr] (West of Sun)
MOON_POSTN:      165.55d {+11h 02m 12s}   +0.81d {+00d 48' 48"}
MOON_DIST:        83.04 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      117.31, 36.26 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      115.76, 71.35 [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.  
COMMENTS:        There is a bright star (mag=6.26) 7.63 arcmin from the BAT position.

GCN Circular #13018
F. Virgili (LJMU), J. Japelj, (U. Ljubljana), C. Guidorzi (U. Ferrara) on behalf of a larger collaboration report:
"The 2-m Liverpool Telescope robotically followed up GRB 120308A (SWIFT trigger 517234) 15.5 min after the GRB trigger time. The automatic "detection mode" procedure detected an uncatalogued afterglow candidate within the XRT error circle at:
14:36:19.97 +79:41:12.4 (J2000)
with magnitude r' = 17.2 mag (vs USNOB1) 18.6 min after the burst.
Observations and analysis are ongoing.
GCN Circular #13019
L. Elenin (KIAM), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
The 0.45-m telescope of ISON-NM observatory robotically followed up the field of the Swift GRB 120308A (Baumgartner et al., GCN 13017 ) on March 8, 06:16:55, i.e. 3.3 minutes after burst trigger. In the first frame of 30 s exposure we do not detect the optical afterglow (Virgili et al., GCN 13018 ) up to R~16m. However in a stacked several first images of 1800 s exposure we clearly detect new source in coordinates 14 36 19.95 +79 41 12.3 which are coincide with coordinates of the optical afterglow (Virgili et al., GCN 13018 ). The magnitude of the source at (UT) 06:38:10 (middle time) is R~17.30m. All images are unfiltered and calibrated against USNO-B1.0 R2 field stars.
All results are preliminary. Observation is continuing.
GCN Circular #13020
A. N. Morgan, C. R. Klein, and J. S. Bloom (UC Berkeley) report:
We observed the field of GRB 120308A (Baumgartner et al., GCN 13017) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2012-Mar-08 07h14m27s UT, ~1.0 hours after the Swift Trigger, under moderate airmass (~1.7). In mosaics (effective exposure time of 0.39 hours) taken simultaneously in the J, H, and Ks filters, we detect the afterglow (Virgili et al., GCN 13018, Elenin et al., GCN 13019) at the Liverpool position (Virgili et al., GCN 13018).
The preliminary photometry yields:
```
post burst
t_mid (hr) exp.(hr) filt  mag    m_err
1.44       0.39     J     17.71  0.21
1.44       0.39     H     16.74  0.22
1.44       0.39     Ks    16.06  0.25
```
Observations are ongoing. All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.
GCN Circular #13021
J. Gorosabel (IAA-CSIC) and R. Gimeno (IAC), report on behalf of a larger collaboration:
"We observed the field of GRB 120308A (Baumgartner et al., GCNC 13017) with the 82cm IAC80 telescope at the Observatorio del Teide, Tenerife, Spain. The observations were carried in the I-band on March 8.27260--8.28075 UT (18.91-30.65 minutes post burst) with a total exposure time of 5x120s. A preliminary analysis of the individual and combined images detect clearly the optical/NIR afterglow (Virgili et al. GCN 13018, Elenin et al. GCN 13019, Morgan et al. GCN 13020) with a magnitude of I~16.8 with respect to the USNO B1.0 catalogue."
GCN Circular #13022
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), G. Sato (ISAS), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120308A (trigger #517234) (Baumgartner, et al., GCN Circ. 13017). The BAT ground-calculated position is RA, Dec = 219.123, 79.674 deg, which is
```
   RA(J2000)  =  14h 36m 29.5s 
   Dec(J2000) = +79d 40' 25.7" 
```
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 97%.
The mask-weighted light curve shows a mostly smooth peak starting at ~T-30 sec, peaking at ~T+1 sec, and ending at ~T+70 sec. T90 (15-350 keV) is 60.6 +- 17.1 sec (estimated error including systematics).
The time-averaged spectrum from T-24.15 to T+58.20 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.71 +- 0.13. The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.62 sec in the 15-150 keV band is 0.6 +- 0.1 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/517234/BA/
GCN Circular #13023
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1980 s of XRT Photon Counting mode data and 2 UVOT images for GRB 120308A, 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 = 219.08506, +79.68651 which is equivalent to:
```
RA (J2000): 14h 36m 20.41s
Dec (J2000): +79d 41' 11.4"
```
with an uncertainty of 1.9 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 #13024
C. Pagani (U. Leicester), A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU), J.A. Kennea (PSU), M.C. Stroh (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester) and W.H. Baumgartner report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 120308A (Baumgartner et al. GCN Circ. 13017), from 82 s to 30.0 ks after the BAT trigger. The data comprise 190 s in Windowed Timing (WT) mode (the first 9 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 Evans et al. (GCN. Circ 13023).
The late-time light curve (from T0+5.8 ks) can be modelled with a power-law decay with a decay index of alpha=1.29 (+/-0.09).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 3.17 (+0.10, -0.09). The best-fitting absorption column is 1.90 (+0.16, -0.15) x 10^21 cm^-2, in excess of the Galactic value of 2.9 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.61 (+0.09, -0.08) and a best-fitting absorption column of 4.8 (+2.1, -1.9) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.3 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     4.8 (+2.1, -1.9) x 10^20 cm^-2
Galactic foreground: 2.9 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.61 (+0.09, -0.08)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00517234.
This circular is an official product of the Swift-XRT team.
GCN Circular #13025
N. P. M. Kuin (MSSL-UCL) and W. H. Baumgartner (GSFC/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120308A 158 s after the BAT trigger (Baumgartner et al., GCN Circ. 13017). A source consistent with the optical position reported by Virgili et al. (GCN Circ. 13018) is detected in the initial UVOT exposures, but only in the v and b band. In u there is no evidence for a source, which suggests that the source is at a redshift of z < 4, and in case there is no contamination of dust, z ~ 3.2.
The best UVOT position is
```
   RA(J2000)  = 14h 36m 20.05s
   Dec(J2000) = 79d 41' 12.2"
```
with an uncertainty of 0.55" (90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

v                  463          483           20         17.02 +/- 0.17
b                  413          432           19         17.65 +/- 0.13
u                  158         7690         1020        >20.9
w1                 512        13962         1165        >21.3
m2                 636        13409         1415        >21.3
w2                 438         8103          646        >21.5
b                  711          730           19         18.40 +/- 0.25
v                  761         1082           39         18.14 +/- 0.29
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #13026
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 120308A (Baumgartner et al., GCNC 13017) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 012-03-08 12:48:40 UT, (~6.6 h after the burst). We did not find any new point source within the enhanced XRT error circle (Evans et al., GCNC 13023) in all the three bands. We could not detect the previously reported afterglow (Virgili et al., GCNC 13018).
Photometric results of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc    Ic
-----------------------------------------------------
0.30659    13:35:07    2220.0   >19.4  >19.4  >19.0
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #13027
A. N. Morgan, and J. S. Bloom (UC Berkeley) report:
We continued to observe the field of GRB 120308A (Baumgartner et al., GCN 13017) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. The source faded significantly since our first epoch (Morgan et al., GCN 13020), suggesting a temporal decay index of approximately 1.0 during our observations.
The preliminary photometry yields:
```
post burst
t_mid (hr) exp.(hr) filt  mag    m_err
1.55       0.50     J     17.70  0.18
1.55       0.50     H     16.81  0.21
1.55       0.50     Ks    16.00  0.21
5.08       2.09     J     18.92  0.25
5.08       2.09     H     >18.2  3sigUL
5.08       2.09     Ks    >17.3  3sigUL
```
All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values. No further observations are planned.
GCN Circular #13028
J. Gorosabel (IAA-CSIC), P. Kubanek (FZU, Praha), M. Jelinek (IAA-CSIC), report on behalf of a larger collaboration:
"We imaged the field of the Swift GRB 120308A (Baumgartner et al., GCN Circ. 13017) with the 1.23m Calar Alto telescope. The observations were carried out in the I-band on March 8.93056--9.18766 UT (16.1--22.3 hours post burst). No optical source brighter than I=20.8 was found consistent with the optical afterglow coordinates (Virgili et al., GCN Circ. 13018; Kuin et al., GCN Circ. 13025)."
GCN Circular #13030
I. Bikmaev, R.Zhuchkov , N. Sakhibullin (Kazan Federal University), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Khamitov, Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
report:
The field of GRB 120308A (Baumgartner et al., GCN 13017) was observed with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) on March 08, 2012, UT(mean)= 22:35, approximately 16 hours after the burst. A serie of exposures by 300 sec each in Rc filter was obtained at moderate weather conditions.
We marginaly detected optical source at the position of OT (Virgili et al., GCN 13018) and estimated its Rc ~ 22.5 mag in our combined image.
GCN Circular #13031
Jang, M., Im, M. (SNU), & Urata, Y. (NCU)
We observed GRB 120308A (Baumgartner et al., GCN 13017) in R, I-bands with a 1 m telescope at Mt. Lemmon, Arizona, U.S. The obsevation started at 10:51:23 2012-03-08 UT, ~ 4.6 hours after the burst alert.
We alternatively took 6 frames for each filter with the exposure time, 300s. We found a optical afterglow candidate in the stacked I image with a preliminary magnitude, I ~ 18.7 +/- 0.12 mag at mid-point time, 17274 sec after the burst alert on the enhanced XRT position (Evans et al., GCN13023). However, no afterglow candidate was found in the stacked R image.
We thank the LOAO operator, J. Yoon for this observation.
1407.6430 from 25 Jul 14
Shuai Zhang et al.: The magnetization degree of the outflow powering the highly-polarized reverse shock emission of GRB 120308A
GRB 120308A, a long duration $\gamma-$ray burst detected by {\it Swift}, was distinguished by a highly-polarized early optical afterglow emission that strongly suggests an ordered magnetic field component in the emitting region. In this work we model the optical and X-ray emission in the reverse and forward shock scenario and show that the strength of the magnetic field in reverse shock region is $\sim 10$ times stronger than that in the forward shock region. Consequently the outflow powering the highly-polarized reverse shock optical emission was mildly-magnetized at a degree $\sigma \sim$ a few percent. Considering the plausible magnetic energy dissipation in both the acceleration and prompt emission phases of the Gamma-ray Burst (GRB) outflow, the afterglow data of GRB 120308A provides us the compelling evidence that at least for some GRBs a non-ignorable fraction of the energy was released in the form of Poynting-flux, confirming the finding firstly made in the reverse-forward shock emission modeling of the optical afterglow of GRB 990123 (Fan et al. 2002; Zhang et al. 2003).
arXiv:1504.02482 g-band detection: z<4.5
1511.01582 from 6 Nov 15
Mi-Xiang Lan et al.: Polarization Evolution of Early Optical Afterglows of Gamma-Ray Bursts
The central engine and jet composition of gamma-ray bursts (GRBs) remain mysterious. Here we suggest that observations on polarization evolution of early optical afterglows may shed light on these questions. We first study the dynamics of a reverse shock and a forward shock that are generated during the interaction of a relativistic jet and its ambient medium. The jet is likely magnetized with a globally large-scale magnetic field from the central engine. The existence of the reverse shock requires that the magnetization degree of the jet should not be high ($\sigma\leq 1$), so that the jet is mainly composed of baryons and leptons. We then calculate the light curve and polarization evolution of an early optical afterglow, and find that when the polarization position angle changes by $90^\circ$ during the early afterglow, the polarization degree is zero for a toroidal magnetic field but is very likely to be non-zero for an aligned magnetic field. This result would be expected to provide a probe for the central engine of GRBs, because an aligned field configuration could originate from a magnetar central engine and a toroidal field configuration could be produced from a black hole via the Blandford-Znajek mechanism. Finally, for such two kinds of magnetic field configurations, we fit the observed data of the early optical afterglow of GRB 120308A equally well.

Back to JG's homepage

Jochen Greiner, last update: 06-Nov-2015 [Disclaimer]