Gamma-ray Burst 100322

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #10542
  J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), on behalf of the Swift team
  At 7:06:18 on March 22, 2010, Swift-BAT detected a rate increase (trigger #416771). No source was detected onboard. A source was detected in ground analysis at RA, Dec 76.489, +42.685, which is:

  RA (J2000)   05h 05m 57.4s
  DEC (J2000)  +42d 41'07"
  

  with an estimated uncertainty of 4 arcmin (radius, 90% containment). The source is 1 degree from the Galactic plane, and was 70% coded in the BAT field of view.
  The burst was short, consisting of a single peak with T90 of about 1.5 sec, and weak. The spectrum is best fit by a simple powerlaw with a photon index of 1.6 +- 0.3. The fluence from 15-150 keV was 5 +- 3 e-08 ergs/cm2.
  While the burst duration and location near the galactic plane are suggestive of a thermonuclear X-ray burst from a galactic neutron star X-ray binary, the BAT spectrum argues against that interpretation. There are about 360 square degrees within 1 degree of the galactic plane, or ~1% of the entire sky. Thus, it is certainly plausible for this burst to be a cosmological GRB.
  Because no source was detected onboard, there are no automated data products. A Swift TOO has been requested.