Gamma-ray Burst 050202

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 02 Feb 05 04:02:30 UT 
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     104298,   Seg_Num: 0 
GRB_RA:          290.560d {+19h 22m 14s} (J2000),
                 290.646d {+19h 22m 35s} (current),
                 289.710d {+19h 18m 50s} (1950)
GRB_DEC:         -38.720d {-38d 43' 11"} (J2000),
                 -38.710d {-38d 42' 35"} (current),
                 -38.816d {-38d 48' 56"} (1950)
GRB_ERROR:       4.00 [arcmin radius, statistical only]
GRB_INTEN:       1014 [cnts]    Peak=89 [cnts/sec]
TRIGGER_DUR:     0.128 [sec]
BKG_INTEN:       36980 [cnts]  
BKG_TIME:        12904.00 SOD {03:35:04.00} UT
BKG_DUR:         8 [sec]
GRB_DATE:        13403 TJD;    33 DOY;   05/02/02
GRB_TIME:        12914.79 SOD {03:35:14.79} UT
GRB_PHI:         -75.51 [deg]
GRB_THETA:        25.62 [deg]
TRIGGER_INDEX:   33
SOLN_STATUS:     0x3 
RATE_SIGNIF:     17.60 [sigma] 
IMAGE_SIGNIF:    8.00 [sigma]
MERIT_PARAMS:     +0  +0  +0  +0  +0  +0  +0  +0  +0  +0
SUN_POSTN:       315.86d {+21h 03m 26s}  -16.80d {-16d 48' 02"}
SUN_DIST:         31.06 [deg]
MOON_POSTN:      218.45d {+14h 33m 49s}  -16.66d {-16d 39' 47"}
MOON_DIST:        65.92 [deg]
GAL_COORDS:      359.57,-22.23 [deg] galactic lon,lat of the burst (or transient)      
ECL_COORDS:      286.60,-16.46 [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 Notice was ground-reprocessed from flight-data.
COMMENTS:        This appears to be a short burst (~400 msec total).

red DSS finding chart ps-file
GCN notice #3005
J. Tueller (GSFC), L. Antonelli (INAF-OAR), S. Barthelmy, L. Barbier (GSFC), D. Burrows (PSU), J. Cummings (GSFC), E. Fenimore (LANL), N. Gehrels, K. Gendreau (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (LANL), J. Nousek (PSU), D. Palmer (LANL), A. Parsons (GSFC), S. Piranmonte (ASDC), T. Sakamoto (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), A. Wells (Leicester) on behalf of the Swift-BAT team:
Swift-BAT detected a burst at 03:35:14.79 UT. The BAT on-board calculated location is RA,Dec 290.560, -38.720 (J2000) with an uncertainty of 4 arcmin (radius, 3-sigma, including a systematic uncertainty).
This appears to be a short burst (single spike, duration of ~400 msec), dominated by emission in the 25-100 keV band. The peak rate is approximately 3000 ct/s.
However, there are some longer-term variations (~150 sec) in the lowest energy band (15-25 keV). These could be due to (a) magnetospheric variations, (b) variations of the galactic sources in the field of view, or (c) intrinsic GRB variations. When more complete data is available, we should be able to remove this ambiguity.
GCN notice #3006
E. Berger (Carnegie Observatories) and W. Krzeminski (Las Campanas Observatory) report:
"We imaged the 4-arcmin radius error circle of GRB 050202 (GCN 3005) with the Swope 40-inch telescope at Las Campanas Observatory on February 2.40 UT (6 hours after the burst) in R-band. Observations were taken at high airmass and with a high sky background (as the Sun was rising) and as a result reach a limit of only R~16 mag. To this limit we do not find any objects within or near the error circle which are not present in the DSS. We note that with a time delay of six hours, this limit is of similar quality to any of the limits obtained to date (Hurley et al. 2002, ApJ, 567, 447)"
This message may be cited.
GCN notice #3007
D. A. Frail (NRAO) and A. M. Soderberg (Caltech) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the VLA to make observations of the short burst GRB050202 detected by Swift (GCN#3005). The full BAT error circle was imaged at frequencies of 1.43 GHz and 4.86 GHz to an rms noise level of 210 microJy/beam and 40 microJy/beam, respectively. No emission is detected above the 5-sigma level at either frequency.
Further observations are planned."
GCN notice #3009
D. A. Frail (NRAO) and A. M. Soderberg (Caltech) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"A second observation was made with the VLA of the short burst GRB050202 detected by Swift (GCN#3005) on February 3.82 UT. Comparison with the first epoch on February 2.67 UT (GCN#3007) shows no new radio sources in the BAT error circle. The rms noise the images is 267 microJy, 52 microJy, and 100 microJy at 1.43, 4.86 and 8.46 GHz respectively.
No further observations are planned."
GCN notice #3010
T. Sakamoto (GSFC), S. Barthelmy, L. Barbier, J. Cummings (GSFC), E. Fenimore (LANL), N. Gehrels, D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), on behalf of the Swift-BAT team:
We have continued the analysis of Swift-BAT GRB 050202 (Tueller, et al., GCN Circ 3005). The refined position is 290.575, -38.735 (J2000) with an uncertainty of 4 arcmin (radius, statistical plus systematic). We find that the T_90 time for this burst is 0.080 sec. The ~150 sec long-term variation on which the spike rides (Circ 3005) has been shown to be due to Sco X-1. A fluctuation from Sco X-1 also contributed to the larger duration value given in Circ 3005.
We have fit the burst spectrum with power-law: index 1.4 +-/0.3. This short burst is in the intermediate hard range.
In the 15-350 keV band, the fluence is 6.5e-8 erg/cm2 and the peak flux is 4.8 ph/cm2/sec.
We note that the the Swift spacecraft did not slew to this burst because the burst location was within the Sun observing constraint.
GCN notice #3018
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A.J. Castro-Tirado (IAA-CSIC, Granada),=20 I. Bond (Massey Univ., Auckland),=20 P. Kilmartin (Univ. of Canterbury),=20 A. de Ugarte Postigo, J. Gorosabel,=20 M. Jel=EDnek (IAA-CSIC), and Ph. Yock=20 (Univ. of Auckland) report:
"Following the detection by SWIFT of the=20 short/soft GRB 050202 (Tueller et al. GCN=20 Circ. 3005) we imaged the error box with the 0.6 m telescope at Mt. John University Observatory. We obtained 3 x 300s images =20 with the MOA camera (+ wide R-band filter)=20 starting on 2.674 Feb (i.e. 12.6 hr after=20 the event). Observations were performed=20 at high airmass, prior to the sunrise.=20 Comparison of the stacked image with the=20 DSS-2 plates revealed no variable source=20 to about R =3D 20."
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Jochen Greiner, last update: 2-Mar-2005 [Disclaimer]