Gamma-ray Burst 051213

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 13 Dec 05 07:26:05 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     172516,   Seg_Num: 0
GRB_RA:          252.123d {+16h 48m 29s} (J2000),
                 252.252d {+16h 49m 00s} (current),
                 251.040d {+16h 44m 10s} (1950)
GRB_DEC:         -59.207d {-59d 12' 25"} (J2000),
                 -59.217d {-59d 13' 01"} (current),
                 -59.119d {-59d 07' 08"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=2027 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 50-350 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        13717 TJD;   347 DOY;   05/12/13
GRB_TIME:        25984.10 SOD {07:13:04.10} UT
GRB_PHI:         -85.33 [deg]
GRB_THETA:        21.64 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.98 [sigma]
MERIT_PARAMS:     +1  +0  +0  -5  +3  -1 -100  +1 -80  +1 
SUN_POSTN:       260.63d {+17h 22m 30s}  -23.16d {-23d 09' 29"}
SUN_DIST:         36.54 [deg]
MOON_POSTN:       49.81d {+03h 19m 15s}  +21.89d {+21d 53' 22"}
MOON_DIST:       139.40 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      329.40, -9.14 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      258.73,-36.47 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 13.54,-7.53 [deg].

red DSS finding chart ps-file

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 13 Dec 05 07:26:11 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     172516,   Seg_Num: 0
GRB_RA:          252.123d {+16h 48m 29s} (J2000),
                 252.252d {+16h 49m 00s} (current),
                 251.040d {+16h 44m 10s} (1950)
GRB_DEC:         -59.207d {-59d 12' 25"} (J2000),
                 -59.217d {-59d 13' 01"} (current),
                 -59.119d {-59d 07' 08"} (1950)
GRB_DATE:        13717 TJD;   347 DOY;   05/12/13
GRB_TIME:        25984.10 SOD {07:13:04.10} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -85.33 [deg]
GRB_THETA:        21.64 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
LC_URL:          sw00172516000msb.lc
SUN_POSTN:       260.63d {+17h 22m 30s}  -23.16d {-23d 09' 29"}
SUN_DIST:         36.54 [deg]
MOON_POSTN:       49.81d {+03h 19m 15s}  +21.89d {+21d 53' 23"}
MOON_DIST:       139.40 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      329.40, -9.14 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      258.73,-36.47 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is an image trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 13.54,-7.53 [deg].

GCN Circular #4345
T. Mineo (IASF-Pa INAF), S. Barthelmy (GSFC), G. Cusumano (IASF-Pa INAF), N. Gehrels (GSFC), S. Hunsberger (PSU), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. Page (U Leicester), D. Palmer (LANL) on behalf of the Swift team:
At 07:13:04 UT, Swift-BAT triggered and located GRB 051213 (trigger=172516). The BAT on-board calculated location is RA,Dec 252.123d,-59.207d {16h 48m 29s,-59d 12' 25"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The spacecraft did not slew because of the Sun observing constraint. The location is 36 deg from the Sun, and it will not be observable by Swift NFIs for at least three weeks. This was a 64-sec image trigger with a 9-sigma significance in the image domain. The BAT lightcurve shows hints of emission, but it is not possible to separate source variations from background variations in the rate domain. The full data set from the next Malindi downlinks in a few hours will allow the separation of source from background.
GCN Circular #4348
J. Tueller (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), K. Gendreau (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), P. Meszaros (PSU), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), on behalf of the Swift-BAT team:
Using the data set from T-75 to T+300 sec from the recent telemetry downlink, we report on further analysis of GRB 051213 (trigger #172516) (Mineo, et al., GCN 4345). The BAT ground-calculated position is (RA,Dec) = 252.078, -59.229 {16h 48m 18.6s, -59d 13' 42.7"} [deg; J2000] +-1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 68%.
The mask-weighted light curve shows a double-peaked structure, with each episode lasting ~30 seconds and showing a roughly time-symmetrical structure. The first episode peaks at T-7 sec, and the second at T+49 sec and emission returns to background levels between the two episodes. T90 (15-350 keV) is (70 +- 5) sec (estimated error including systematics).
The power law index of the time-averaged spectrum is 1.64 +- 0.20. The fluence in the 15-150 keV band is (8.0 +- 1.0) x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+48.9 sec in the 15-150 keV band is (0.51 +- 0.14) ph/cm2/sec. All the quoted errors are at the 90% confidence level.
We are classifying this event as GRB, but given the soft spectrum and long duration, we can not rule out that it is a hard x-ray transient.

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Jochen Greiner, last update: 13-Dec-2005 [Disclaimer]