Gamma-ray Burst 100203A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #10360
  J. R. Cummings (NASA/GSFC/CRESST), H. A. Krimm (NASA/GSFC/CRESST), F. E. Marshall (GSFC), D. M. Palmer (LANL) report on behalf of the Swift-BAT team:
  At 18:31:07 UTC on Feb-03-2010, BAT triggered on GRB 100203A. The source was detected onboard at a significance too low to trigger an automated response. In ground analysis, a source was found at RA, Dec = 96.225, +4.793, which is

  RA (J2000) 06h 24m 54s
  Dec (J2000) 4d 47' 33"
  

  with an estimated uncertainty of 2 arcmin radius (90% containment).
  The Galactic coordinates of the source are 205.629, -3.690. While the event appears to be a faint, soft, long GRB, we cannot completely discount the possibility of it being a Galactic transient.
  The lightcurve shows 3 well-separated peaks, each about 10 seconds long, at T-50, T+0, and T+60 seconds.
  A 4 ksec follow-up observation with the Swift XRT and UVOT has been scheduled.
• GCN Circular #10368
  R.L.C. Starling (U Leicester), E.A. Hoversten (PSU) and F.E. Marshall (NASA/GSFC) report on behalf of the Swift XRT and UVOT teams:
  We observed the Swift GRB 100203A, detected in ground analysis (Cummings et al. GCN Circ. 10360), with Swift XRT and UVOT beginning 25.66 hours (92.3 ks) after the BAT trigger (#411011).
  The XRT observed the field for 3.85 ks. No source has been detected at the 3-sigma confidence level or above, with a 3-sigma upper limit on the count rate at the BAT position of 6 x 10^-3 ct s^-1. We note that this source lies near the Galactic Plane, where Galactic absorption in this direction is high, at 5.3 x 10^21 cm^-2.
  The UVOT observed the field of GRB 100203A in the uvm2 filter. Visual comparison with DSS images of the field reveal no afterglow candidates. Given the low Galactic latitude, afterglow detection is complicated by high extinction and numerous bright stars in the field.
  The observed 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for initial exposures are:

  Filter   T_start(s)   T_stop(s)   Exp(s)   3-sigma upper limit
  =============================================================
  uvm2       92604       103268      3915         > 21.27
  

  The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.55 in the direction of the burst (Schlegel et al. 1998).
  This circular is an official product of the Swift team.
• GCN Report 272.1
  GCN_Report 272.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_272_1.pdf by F.E.Marshall at NASA/GSFC titled: "Final Swift Observations of GRB 100203A"