Gamma-ray Burst 100728B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:32:11 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     302005916
GRB_RA:           55.250d {+03h 41m 00s} (J2000),
                  55.386d {+03h 41m 33s} (current),
                  54.609d {+03h 38m 26s} (1950)
GRB_DEC:          +0.250d {+00d 15' 00"} (J2000),
                  +0.283d {+00d 17' 01"} (current),
                  +0.090d {+00d 05' 24"} (1950)
GRB_ERROR:       12.92 [deg radius, statistical plus systematic]
GRB_INTEN:       160 [cnts/sec]
DATA_SIGNIF:     9.40 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        15405 TJD;   209 DOY;   10/07/28
GRB_TIME:        37914.97 SOD {10:31:54.97} UT
GRB_PHI:         242.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      1.17
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 1,1,0, 0,0,0, 0,0,
SUN_POSTN:       127.61d {+08h 30m 27s}  +18.95d {+18d 57' 13"}
SUN_DIST:         73.12 [deg]   Sun_angle= 4.8 [hr] (West of Sun)
MOON_POSTN:      331.85d {+22h 07m 24s}   -7.29d {-07d 17' 20"}
MOON_DIST:        83.63 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      186.12,-40.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       52.97,-18.83 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 10.35,-6.03 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:32:16 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     430172,   Seg_Num: 0
GRB_RA:           44.053d {+02h 56m 13s} (J2000),
                  44.189d {+02h 56m 45s} (current),
                  43.412d {+02h 53m 39s} (1950)
GRB_DEC:          +0.280d {+00d 16' 46"} (J2000),
                  +0.322d {+00d 19' 18"} (current),
                  +0.078d {+00d 04' 42"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5320 [cnts]    Image_Peak=147 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   147     E_range: 25-100 keV
BKG_INTEN:       31278 [cnts]
BKG_TIME:        37897.97 SOD {10:31:37.97} UT
BKG_DUR:         8 [sec]
GRB_DATE:        15405 TJD;   209 DOY;   10/07/28
GRB_TIME:        37915.82 SOD {10:31:55.82} UT
GRB_PHI:         146.26 [deg]
GRB_THETA:        46.84 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     22.44 [sigma]
IMAGE_SIGNIF:    9.07 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +0  +0  +0 -10  +0 
SUN_POSTN:       127.61d {+08h 30m 27s}  +18.95d {+18d 57' 12"}
SUN_DIST:         83.68 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      331.85d {+22h 07m 24s}   -7.29d {-07d 17' 19"}
MOON_DIST:        72.53 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.38 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       41.68,-15.79 [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 = 9.07,-1.38 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:32:21 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      57
TRIGGER_NUM:     302005916
GRB_RA:           51.617d {+03h 26m 28s} (J2000),
                  51.755d {+03h 27m 01s} (current),
                  50.964d {+03h 23m 51s} (1950)
GRB_DEC:          +3.217d {+03d 12' 60"} (J2000),
                  +3.253d {+03d 15' 11"} (current),
                  +3.042d {+03d 02' 33"} (1950)
GRB_ERROR:       9.47 [deg radius, statistical plus systematic]
GRB_INTEN:       191 [cnts/sec]
DATA_SIGNIF:     14.40 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        15405 TJD;   209 DOY;   10/07/28
GRB_TIME:        37914.97 SOD {10:31:54.97} UT
GRB_PHI:         236.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.37
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 1,1,0, 0,0,0, 0,0,
SUN_POSTN:       127.61d {+08h 30m 27s}  +18.95d {+18d 57' 12"}
SUN_DIST:         75.57 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:      331.85d {+22h 07m 24s}   -7.29d {-07d 17' 18"}
MOON_DIST:        80.42 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      179.99,-41.86 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       50.06,-15.06 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 10.35,-6.03 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:37:17 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     2768131,   Seg_Num: 67
GRB_RA:           44.053d {+02h 56m 13s} (J2000),
                  44.189d {+02h 56m 45s} (current),
                  43.412d {+02h 53m 39s} (1950)
GRB_DEC:          +0.280d {+00d 16' 46"} (J2000),
                  +0.322d {+00d 19' 18"} (current),
                  +0.078d {+00d 04' 42"} (1950)
GRB_DATE:        15405 TJD;   209 DOY;   10/07/28
GRB_TIME:        37915.82 SOD {10:31:55.82} UT
TRIGGER_INDEX:   147
GRB_PHI:         146.26 [deg]
GRB_THETA:        46.84 [deg]
DELTA_TIME:      -31483.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    0.00 [sigma]
LC_URL:          sw00430172000msb.lc
SUN_POSTN:       127.62d {+08h 30m 28s}  +18.95d {+18d 57' 10"}
SUN_DIST:         83.68 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      331.89d {+22h 07m 33s}   -7.27d {-07d 16' 19"}
MOON_DIST:        72.49 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.38 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       41.68,-15.79 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!  
COMMENTS:           
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 = 9.07,-1.38 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:48:41 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     430172,   Seg_Num: 0
POINT_RA:         44.040d {+02h 56m 10s} (J2000)
POINT_DEC:        +0.269d {+00d 16' 08"} (J2000)
IMG_START_DATE:  15405 TJD;   209 DOY;   10/07/28
IMG_START_TIME:  38012.85 SOD {10:33:32.85} UT,   97.0 [sec] since BAT Trigger Time
COUNTS:          17    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    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:     Wed 28 Jul 10 10:52:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     430172,   Seg_Num: 0
POINT_RA:         44.041d {+02h 56m 10s} (J2000)
POINT_DEC:        +0.269d {+00d 16' 08"} (J2000)
POINT_ROLL:      70.942d
IMG_START_DATE:  15405 TJD;   209 DOY;   10/07/28
IMG_START_TIME:  38016.75 SOD {10:33:36.75} UT,   100.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.949
N_STARS:         15
X_OFFSET:        538 [pixels]
Y_OFFSET:        462 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1421 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    17
SL_URL:          sw00430172000msufc0100.fits
SUN_POSTN:       127.63d {+08h 30m 30s}  +18.95d {+18d 57' 01"}
SUN_DIST:         83.70 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      332.00d {+22h 08m 01s}   -7.22d {-07d 13' 15"}
MOON_DIST:        72.36 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       41.66,-15.80 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:52:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     430172,   Seg_Num: 0
POINT_RA:         44.041d {+02h 56m 10s} (J2000)
POINT_DEC:        +0.269d {+00d 16' 08"} (J2000)
POINT_ROLL:      70.942d
IMG_START_DATE:  15405 TJD;   209 DOY;   10/07/28
IMG_START_TIME:  38016.75 SOD {10:33:36.75} UT,   100.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.949
N_STARS:         15
X_OFFSET:        538 [pixels]
Y_OFFSET:        462 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1421 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    17
SL_URL:          sw00430172000msufc0100.fits
SUN_POSTN:       127.63d {+08h 30m 30s}  +18.95d {+18d 57' 01"}
SUN_DIST:         83.70 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      332.00d {+22h 08m 01s}   -7.22d {-07d 13' 15"}
MOON_DIST:        72.36 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       41.66,-15.80 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:52:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     430172,   Seg_Num: 0
POINT_RA:         44.041d {+02h 56m 10s} (J2000)
POINT_DEC:        +0.269d {+00d 16' 08"} (J2000)
POINT_ROLL:      70.942d
IMG_START_DATE:  15405 TJD;   209 DOY;   10/07/28
IMG_START_TIME:  38016.75 SOD {10:33:36.75} UT,   100.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.949
N_STARS:         15
X_OFFSET:        538 [pixels]
Y_OFFSET:        462 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1421 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    17
SL_URL:          sw00430172000msufc0100.fits
SUN_POSTN:       127.63d {+08h 30m 30s}  +18.95d {+18d 57' 00"}
SUN_DIST:         83.70 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      332.01d {+22h 08m 01s}   -7.22d {-07d 13' 10"}
MOON_DIST:        72.36 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       41.66,-15.80 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:54:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     430172,   Seg_Num: 0
POINT_RA:         44.041d {+02h 56m 10s} (J2000)
POINT_DEC:        +0.269d {+00d 16' 08"} (J2000)
ROLL:            70.942d
IMG_START_DATE:  15405 TJD;   209 DOY;   10/07/28
IMG_START_TIME:  38016.75 SOD {10:33:36.75} UT,   100.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     302006022
X_OFFSET:        857 [pixels]
Y_OFFSET:        781 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1017
Y_GRB_POS:       941
BINNING_INDEX:   1
IM_URL:          sw00430172000msuni0107.fits
SUN_POSTN:       127.63d {+08h 30m 30s}  +18.95d {+18d 56' 60"}
SUN_DIST:         83.71 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      332.01d {+22h 08m 04s}   -7.22d {-07d 12' 56"}
MOON_DIST:        72.35 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       41.66,-15.80 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:54:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     430172,   Seg_Num: 0
POINT_RA:         44.041d {+02h 56m 10s} (J2000)
POINT_DEC:        +0.269d {+00d 16' 08"} (J2000)
ROLL:            70.942d
IMG_START_DATE:  15405 TJD;   209 DOY;   10/07/28
IMG_START_TIME:  38016.75 SOD {10:33:36.75} UT,   100.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     302006022
X_OFFSET:        857 [pixels]
Y_OFFSET:        781 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1017
Y_GRB_POS:       941
BINNING_INDEX:   1
IM_URL:          sw00430172000msuni0107.fits
SUN_POSTN:       127.63d {+08h 30m 30s}  +18.95d {+18d 56' 60"}
SUN_DIST:         83.71 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      332.02d {+22h 08m 04s}   -7.22d {-07d 12' 53"}
MOON_DIST:        72.35 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       41.66,-15.80 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 28 Jul 10 10:58:51 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     430172,   Seg_Num: 0
GRB_RA:           44.0561d {+02h 56m 13.46s} (J2000),
                  44.1918d {+02h 56m 46.02s} (current),
                  43.4150d {+02h 53m 39.59s} (1950)
GRB_DEC:          +0.2811d {+00d 16' 51.9"} (J2000),
                  +0.3233d {+00d 19' 24.0"} (current),
                  +0.0799d {+00d 04' 47.7"} (1950)
GRB_ERROR:       0.8 [arcsec radius, statistical only]
GRB_MAG:         17.29 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  15405 TJD;   209 DOY;   10/07/28
IMG_START_TIME:  38020.00 SOD {10:33:40.00} UT,   104.2 [sec] since BAT Trigger Time
SUN_POSTN:       127.63d {+08h 30m 31s}  +18.95d {+18d 56' 57"}
SUN_DIST:         83.69 [deg]   Sun_angle= 5.6 [hr] (West of Sun)
MOON_POSTN:      332.05d {+22h 08m 12s}   -7.20d {-07d 11' 59"}
MOON_DIST:        72.33 [deg]
MOON_ILLUM:      95 [%]
GAL_COORDS:      175.64,-49.38 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       41.68,-15.79 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN Circular #11007
D. A. Perley, C. R. Klein, A. N. Morgan, and W. Li (UC Berkeley) report on behalf of the KAIT follow-up team:
The Katzman Automatic Imaging Telescope (KAIT) responded to GRB 100728A and began taking data starting less than one minute after the trigger. A moderately bright optical transient not present in DSS survey imaging is visible in the initial set of exposures at the following position:
```
  
RA  =  02:56:13.48
dec = +00:16:51.8
```
(J2000) We measure I = 18.7 +/- 0.3 mag at 10:33:51 UT (t = 95 secs after the BAT trigger)
In addition, we also manually slewed the 1.0 meter Nickel telescope and began taking data starting at 6.6 minutes after the trigger; the afterglow is also well-detected and is seen to fade in subsequent exposures. Follow-up is continuing.
GCN Circular #11008
K. Ivarsen, J. Haislip, D. Reichart, A. LaCluyze, J. Moore, A. Foster, R. Egger, A. Oza, M. Schubel, A. Trotter, J. A. Crain, and M. Nysewander report:
Skynet observed the Swift/BAT localization of GRB 100728A (Swift trigger #430172) with four of the 16" PROMPT telescopes at CTIO beginning 45 seconds after the trigger in BVRI. We detect the afterglow in all filters.
At 50 seconds after the trigger, its magnitude is I = 14.62 +0.08 -0.07 (calibrated to 10 SDSS stars), R = 15.24 +0.07, -0.06 (calibrated to 7 SDSS stars), V = 15.78, +0.08, -0.07 (calibrated to 8 SDSS stars), B = 16.54 +0.21, -0.17 (calibrated to 2 SDSS stars). SDSS transformations were applied using Jester et al., 2005, ApJ, 130, 873.
PROMPT's BVRI light curve of the first 4.3 minutes after the trigger, calibrated to SDSS stars, can be found here: http://skynet.unc.edu/grb/grb100728a.png. Further observations were limited by morning twilight at PROMPT.
GCN Circular #11009
D. C. Morris (GWU/GSFC), A. P. Beardmore (U Leicester), V. D'Elia (ASDC), P. A. Evans (U Leicester), J. M. Gelbord (PSU), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), O. M. Littlejohns (U Leicester), C. B. Markwardt (CRESST/GSFC/UMD), J. P. Osborne (U Leicester), C. Pagani (U Leicester), K. L. Page (U Leicester), A. Rowlinson (U Leicester), B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team:
At 10:31:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 100728B (trigger=430172). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 44.053, +0.280 which is
```
    RA(J2000) = 02h 56m 13s
    Dec(J2000) = +00d 16' 46"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 10 sec plus some possible precursor activity. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 10:33:32.9 UT, 97.0 seconds after the BAT trigger. No source was detected in the first 2.5 seconds image. The XRT observed the field for approximately 80 seconds in WT mode. The prompt spectrum from the WT data shows evidence of a source. Due to an observing constraint no additional PC data were taken to allow XRT to centroid on the afterglow and derive a position. We are waiting for the full dataset to detect and localise the XRT counterpart.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 100 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
   RA(J2000)  =	02:56:13.46 = 44.05607
   DEC(J2000) = +00:16:51.9  =  0.28109
```
with a 90%-confidence error radius of about 0.75 arc sec. This position is 11.7 arc sec. from the center of the BAT error circle. The estimated magnitude is 17.30 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07.
Burst Advocate for this burst is D. C. Morris (david.c.morris AT 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 Circular #11010
D. A. Perley, A. N. Morgan, and C. R. Klein (UC Berkeley) report:
The burst observed in our previous circular was in fact 100728B (Swift trigger #430172), and not 100728A (#430151, Cannizzo et al., GCN 11004).
We apologize for any confusion this may have caused.
GCN Circular #11011
K. Ivarsen, J. Haislip, D. Reichart, A. LaCluyze, J. Moore, A. Foster, R. Egger, A. Oza, M. Schubel, A. Trotter, J. A. Crain, and M. Nysewander
The observations reported in GCN #11008 (Swift trigger #430172) should refer to GRB 100728B rather than GRB 100728A.
We observed the optical transient at the following position:
```
RA  = 02:56:13.51
Dec = +00:16:52.16
```
We apologize for any inconvenience this may have caused.
GCN Circular #11012
L. Elenin (ISON), I. Molotov (ISON), A. Pozanenko (IKI) report on behalf= of=20 larger GRB follow-up collaboration:
We observed the field of the Swift GRB 100728B (Page et al. GCN 11009) w= ith=20 0.45-m astrograph f/2.8 =CFf ISON-NM observatory (32d 54' 11.64'', 105d = 31'=20 42. 34'' ) starting July 28 (UT) 10:56:08, i.e. 24 minutes after burst=20 onset. A few unfiltered 300s exposures were taken before down. In a firs= t=20 exposures we clearly detect the afterglow at the position (J2000) RA=3D 0= 2 56=20 13.48 Dec=3D +00 16 51.4 which coincides with early afterglow detection=20 (Perley et al. GCN 11007; Page et al. GCN 11009).
A preliminary photometry of unfiltered exposures against USNO-B1.0 field=20 stars (R-filter) at 29.3 minutes after burst is 19m.=20
GCN Circular #11013
F. Olivares, R. Filgas and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 100728B (Swift trigger 430172; Morris et al., GCN #11009) simultaneously in JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile).
Observations started at 10:34 UT, 2 minutes after the GRB trigger. They were performed during astronomical twilight at an average airmass of 1.2.
We detect a single point source at position reported by Perley et al. (GCN #11007), Morris et al. (GCN #11009), Ivarsen et al. (GCN #11011) and Elenin et al. (GCN #11012).
Based on the first 4 min of total exposures in JHK, we estimate preliminary magnitudes (all in AB system) of
```
J = 16.4 +- 0.1 mag,
H = 16.2 +- 0.1 mag and
K = 16.0 +- 0.1 mag
```
Given magnitudes are calibrated against 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.07 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #11015
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 10:31:54.97 UT on 28 July 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100728B (trigger 302005916 / 100728439), which was also detected by the Swift-BAT (Morris et al. 2008, GCN 11009) The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 57.1 degrees.
The GBM light curve shows a single pulse with a duration (T90) of about 11.8 +/- 2.4 s (50-300 keV). The time-averaged spectrum from T0-1.024 s to T0+5.632 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -0.9 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 131 +/- 15 keV (chi squared 1043 for 599 d.o.f.).
The event fluence (8-1000 keV) in this time interval is (2.4 +/- 0.1)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+1.22 s in the 8-1000 keV band is 6.2 +/- 0.2 ph/s/cm^2.
A Band function fits the spectrum equally well (chi squared 1037 for 598 d.o.f.) with Epeak= 104 +/- 14 keV, alpha = -0.8 +/- 0.2 and beta = -2.2 +/-0.2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #11017
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 820 s of XRT Photon Counting mode data and 2 UVOT images, 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 = 44.05620, 0.28120 which is equivalent to:
```
RA (J2000):  02 56 13.48
Dec (J2000): +00 16 52.5
```
with an uncertainty of 2.0 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 is an official product of the Swift-XRT team.
GCN Circular #11022
C. Pagani (U. Leicester) and D. C. Morris (GWU/GSFC) report on behalf of the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 100728B (Morris et al. GCN Circ. 11009), from 81 s to 17.4 ks after the BAT trigger. The data comprise 86 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 11017).
The light curve can be modelled with a power-law decay with a decay index of alpha=1.109 (+0.029, -0.030).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.20 (+/-0.20). The best-fitting absorption column is 1.2 (+0.4, -0.5) x 10^21 cm^-2, in excess of the Galactic value of 6.2 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of 1.109, the count rate at T+24 hours will be 5.0 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x 10^-13 (2.5 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/00430172.
This circular is an official product of the Swift-XRT team.
GCN Circular #11023
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/UMD), D. C. Morris (GWU/GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+350 sec from the recent telemetry downlink, we report further analysis of BAT GRB 100728B (trigger #430172) (Morris, et al., GCN Circ. 11009). The BAT ground-calculated position is RA, Dec = 44.051, 0.296 deg which is
```
    RA(J2000)  =  02h 56m 12.2s
    Dec(J2000) = +00d 17' 45.9"
```
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 11%.
The mask-weighted light curve shows a single peak of duration 10 seconds, starting at T-2 sec and continuing at a low level to about T+20 sec. An observing constraint moved the burst out of the BAT field of view at T+350 sec, but there is no sign of extended emission from this burst. T90 (15-350 keV) is 12.1 +- 2.4 sec (estimated error including systematics).
The time-averaged spectrum from T-1.7 to T+13.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.55 +- 0.14. The fluence in the 15-150 keV band is 1.7 +- 0.1 x 10-6 erg/cm2. The 1-sec peak photon flux measured from T+0.18 sec in the 15-150 keV band is 3.5 +- 0.5 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/430172/BA/
GCN Circular #11024
D. A. Perley, W. Li, and A. V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB follow-up team:
The Katzman Automatic Imaging Telescope (KAIT) began observations of GRB 100728B (Morris et al., GCN 11009) at 30 sec after the trigger time (10 sec after the GCN notice), and continued to track the afterglow in a combination of V, I, and unfiltered exposures until shut down by morning twilight. The afterglow remains detected throughout this period.
An series of 2-second frames taken between 30-64 sec clearly shows a rapid rise from an initial mag of ~16.5 (calibrated to USNO B1.0) to a peak of 16.1 mag at ~50 seconds. The afterglow decays as an unbroken power-law with decay index alpha=0.97 after that time through the end of our observations at 5700 s.
A subset of the unfiltered photometry is presented below:
```
tstart(s) exp(s) mag      unc
149       20    17.02 +/- 0.02
249       20    17.61 +/- 0.03
446       20    18.21 +/- 0.05
643       20    18.51 +/- 0.07
846       20    18.90 +/- 0.07
1141      60    19.15 +/- 0.07
1440      60    19.40 +/- 0.07
1668      60    19.76 +/- 0.10
2264     100    19.81 +/- 0.10
3326     100    19.86 +/- 0.08
4186     140    20.33 +/- 0.10
5115     140    20.58 +/- 0.14
5544     200    20.88 +/- 0.19
```
All times are referenced to the BAT trigger at 10:31:55 UT. Magnitudes are calibrated relative to USNO B1.0 standards in the field.
Further analysis is in progress. We note that the I-band magnitude in our previous circular (GCN 11007) was calibrated to USNO R-band standards and should not be relied upon for detailed analysis. In addition, the time from burst specified in that circular is relative to the BAT position notice time, rather than the trigger time as specified. (The UT time given is correct as stated.)
GCN Circular #11025
D. A. Perley, C. R. Klein, and A. N. Morgan (UC Berkeley) report:
We began observations of the afterglow of GRB 100728B (Morris et al., GCN 11009; Perley et al., GCN 11007) with the Nickel 40-inch telescope at Lick Observatory starting at 10:38:32 UT, 397 sec after the Swift trigger. A series of frames in R-band (as well as one V-band and one U-band exposure) was acquired. The resulting light curve shows a gradual, unbroken power-law decay with a decay index consistent with that seen in the KAIT observations (Perley et al., GCN 11024). Photometry from our first seven R-band exposures is as follows:
```
tstart(s) exp(s) filt  mag    unc
397        60    R = 17.38 +/- 0.06
830       300    R = 18.33 +/- 0.05
1162      300    R = 18.53 +/- 0.06
1497      200    R = 18.71 +/- 0.07
1888      160    R = 18.88 +/- 0.09
2062      120    R = 18.80 +/- 0.09
2197      120    R = 18.99 +/- 0.11
```
Calibration is relative to a single bright star at RA=44.041108, dec=+0.242409 (SDSS DR6 magnitudes g=15.61, r=14.52, i=14.57; the equivalent Cousins R magnitude is R=14.3 using the average of the two SDSS Lupton transformations.) As this star may be weakly blended with a faint neighbor and its USNO magnitude (R2=13.94) differs from this SDSS value, caution is advised in interpreting the absolute calibration.
GCN Circular #11026
S. R. Oates (MSSL-UCL) and D. C. Morris (GWU/GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began observerving the field of GRB 100728B 101s after the BAT trigger (Morris et al., GCN Circ. 11009). We detect the optical afterglow in the white, v, b and u filters only.
The refined UVOT position is RA (J2000)= 163.48809, DEC (J2000)=-45.47265, which is equivalent to:
```
      RA (J2000) = 02:56:13.467
     Dec (J2000) = +00:16:52.18
```
with an estimated uncertainty of 0.52 arcsec (radius, 90% confidence).
This position is consistent with the XRT refined position (Evans et al., GCN Circ 11017) and with the optical afterglow positions reported by KAIT (Perley et al., GCN Circ 11007, 11010 & 11024), PROMPT (Ivarsen et al., GCN Circ 11008, 11011) & the SON-NM observatory (Elenin et al., GCN Circ 11012). The non-detection in the UV filters suggests a photometric redshift of z~2.8.
Preliminary magnitudes and the 3 sigma upper limits are reported below for individual optical images and summed UV images.
```
Filter    T_start(s)  T_stop(s)  Exposure    Mag/3SigUL
###########################################################
white     101          251         147        17.43 +/- 0.08
white     4713         4913	   197	      20.62 +/- 0.22
v         3687         3887        197	      20.19 +/- 0.56
b         4509         4709	   197	      20.47 +/- 0.33
u	  4303         4503	   197	      19.90 +/- 0.28
uvw1	  4098         6050	   294	      > 20.50
uvm2      3892         5529	   393	      > 20.52
uvw2      3482         5119	   393	      > 20.93
###########################################################
```
The above magnitudes are not corrected for the Galactic extinction corresponding to a non-negligible reddening of E_{B-V} = 0.07 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383,627).
GCN Circular #11027
A. De Cia (University of Iceland), D. Malesani (DARK/NBI), P.M. Vreeswijk, S. Schulze and P. Jakobsson (University of Iceland) report:
We observed the field of GRB 100728B (Morris et al., GCN 11009) with the NOT equipped with StanCam, under poor seeing conditions. Observations were carried out in the R filter for 40 minutes, with mean time 18.36 hours after the GRB trigger. The seeing was 1.3".
At the position of the optical afterglow (Perley et al., GCN 11007; Morris et al., GCN 11009) we do not detect any clear source, down to a limiting mag R > 22.2. By smoothing the image, a weak source can be marginally detected with magnitude R = 22.5 +/- 0.5 mag, calibrated against SDSS stars converted to Vega.
We acknowledge the careful assistence of the NOT staff, in particular Anders Thygesen.
GCN Circular #11028
The coordinates in circular 11026 should be
RA (J2000)= 0.28116, DEC (J2000)=44.05611, which is equivalent to:
```
RA (J2000) = 02:56:13.467
Dec (J2000) = +00:16:52.18
```
The coordinates in the degree format in circular 11026 were accidentally taken from a different GRB.
GCN Circular #11029
Apologies, the coordinates in circular 11028 should be RA (J2000)= 44.05611, DEC (J2000)=0.28116
GCN Circular #11045
A. Volnova (SAI MASU), L. Elenin, I. Molotov (ISON), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 100728B (Morris et al. GCN 11009) with 0.45-m telescope =CFf ISON-NM observatory on July 28 (Elenin at al., GCN 11012).
The afterglow ( Perley et al. GCN 11007; Morris et al. GCN 11009; Ivarsen et al. GCN 11011) is detectable on each of four images taken between July 28 (UT) 10:45:49 - 11:01:14.
A photometry of unfiltered images against SDSS field stars and R-mag=20 obtained with Lupton transformations is following
```
t-t0,  filter, exposure,  OT
(sec)

 984  W     300            18.36+/-0.17
1294  W     300            18.93+/-0.22
1603  W     300            18.80+/-0.18
1909  W     300            19.00+/-0.30
```
Finding chart and SDSS calibration stars can be found at http://grb.rssi.ru/GRB100728B/100728b-refstars.png
GCN Circular #11317
H. Flores (GEPI/Obs. de Paris), J. P. U. Fynbo, A. de Ugarte Postigo, B. Milvang-Jensen, D. Malesani (DARK/NBI), P. Goldoni (APC/Univ. Paris 7 and SAp/CEA), C. C. Thoene (IAA-CSIC Granada), S. Piranomonte (INAF/Roma), S. D. Vergani (GEPI/Obs. de Paris) report on behalf of the X-Shooter GRB collaboration:
We have observed the afterglow of the GRB 100728B (Morris et al., GCN 11009; Perley et al., GCN 11010) with the ESO VLT equipped with the X-shooter spectrograph. The observation started on 2010-07-29 at 08:15 UT (22 hr after the GRB). A total exposure of 4x600 s was obtained, covering the spectral range from 300 to 2500 nm. Due to technical problems with the atmospheric dispersion corrector, the sensitivity of the instrument was below the nominal value during this observation so the signal-to-noise ratio of the spectrum is very low.
In the spectra we detect a broad absorption line consistent with a damped Lyman-alpha line and absorption features consistent with the MgII doublet at a common redshift of z=2.106. Given the low S/N of the spectrum, this redshift measurement should be considered tentative.
We acknowledge the Paranal staff, in particular Alain Smette, for valuable support with the observations, and Daniel Perley (Berkeley) for providing us a finding chart with the afterglow.

Back to JG's homepage

Jochen Greiner, last update: 07-Oct-2010 [Disclaimer]