Gamma-ray Burst 010213

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN notice #934
  G. Ricker, D. Lamb, and S. Woosley on behalf of the HETE Science Team;
  R. Vanderspek, G. Crew, J. Doty, G. Monnelly, J. Villasenor; N. Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, G. Pizzichini, and G. Prigozhin, on behalf of the HETE Operations and HETE Optical-SXC Teams;
  N. Kawai, M. Matsuoka, Y. Shirasaki, T. Tamagawa, A. Yoshida, E. Fenimore, M. Galassi, and C. Graziani, on behalf of the HETE WXM Team;
  J-L Atteia, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team;
  write:
  On 13 February 2001 at 12:35:35 UTC, a soft spectrum, high energy transient at high galactic latitude was detected and localized by HETE. Both the WXM and the FREGATE instruments detected the event. Although the WXM and FREGATE cover extremely broad energy bands (WXM: 2-25 keV; FREGATE: 6-500 keV), the burst event was only detectable in the 2-18 keV band by WXM, and in the 6-10 keV band by FREGATE. Because of the unusual spectrum of the transient, neither instrument triggered.
  The preliminary coordinates of the burst are RA= 10h 31m 36s, Dec= +5d 30' 39" (J2000), derived from combining data from the WXM and Boresighted Optical Cameras. The statistical error radius in the WXM localization is 3.5 arcmin (95% confidence). In addition, we estimate a systematic error radius at present of 30 arcmin about this location. The spacecraft aspect was known to an accuracy of +/- 30 arcsec (95% confidence) from the optical cameras, and will be improved.
  The burst exhibited a double-peaked structure and lasted about 30 seconds. The incident flux measured with the WXM (2-18 keV) at the first peak is about 0.7 Crab, and at the second peak is about 2.4 Crab. The spectrum in the 2-18 keV range was harder than that of the Crab nebula at the first peak, and softer than that of the Crab at the second peak. The peak flux seen with FREGATE (6-10 keV) was ~2 Crab. Assuming a Crab-like spectrum, the peak energy flux was ~1.5 E-8 erg/cm^2/sec in the 6-10 keV range.
  The high galactic latitude of the source, well away from the Galactic Bulge, and the shape of its light curve suggest that it is a gamma-ray burst with a very unusual spectrum, perhaps similar to those reported for "X-ray rich" GRBs by Heise et al (2001) from BeppoSAX observations. Conceivably, it could instead be a nearby X-ray burst source. A preliminary catalog search of the WXM error circle revealed no correspondence with known globular sources, cataclysmic variables, low mass X-ray binaries, or flare stars.
  Follow-up observations of this unusual transient are encouraged.
  Additional information on the 13 February high energy transient (including light curves, the WXM error box and results from the preliminary catalog searches), as well as the HETE mission, is available at: http://space.mit.edu/HETE/
  

  Acronyms:
  HETE=High Energy Transient Explorer
  FREGATE=French Gamma Ray Telescope
  WXM=Wide Field X-ray Monitor
  SXC=Soft X-ray Camera
  

• GCN notice #936
  M. Boer, J.-L. Atteia, and A. Klotz, on behalf of the TAROT team report:
  TAROT observed the source of GRB 010213 (Ricker et al., GCN Circ 934). The observations were performed between 1h48 and 2h00 on Feb. 15, 2001, i.e. about 38 hours after the burst, with a limiting magnitude of 17 (no filter). A comparison with the USNO A2.0 catalog does not show any new source 30arcmin around the center of the HETE error box.
  This message may be cited.
• GCN notice #940
  A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
  We have imaged the inner 6.5x6.5 arcmin portion of the HETE error circle with the USNOFS 1.55-m telescope and the ASTROCAM infrared camera at H-band, starting at 010215.42 UT. Poor seeing conditions limited the depth of the image, but the limiting magnitude is approximately equivalent to that of the POSS-IIF red plate for this field. We find no object that does not have a counterpart on the POSS-II plate.
• GCN notice #941
  R. Hudec, M. Jelinek, Astronomical Institute Ondrejov, Czech Republic, M. Tichy, J. Ticha, Klet Observatory, Czech Republic, report:
  Unfiltered optical images of the GRB010213 HETE error box (GCN#934) were acquired on 2001 January 15.09 with the 0.57-meter f/5.2 telescope (+CCD camera SBIG ST-8) of the Klet Observatory, Czech Republic, for a total exposure time of 600 sec.
  No new or noticeable object down to a magnitude ~20.5 is detected inside the trigger error box when we compare our summed frame with the DSS-II Digital Sky Survey.
  This message can be cited.
• GCN notice #945
  E. Berger (Caltech) and D. A. Frail (NRAO) report on behalf of a larger collaboration:
  "Beginning on February 15.42 UT we observed the inner ~25% of the HETE II error circle of GRB010213 (GCN#934) with the VLA at 1.43 GHz. Inside this region we detect one weak source, which is not cataloged in the NRAO VLA Sky Survey (NVSS), at RA=10:31:08.08, DEC=5:32:08.26 with a conservative error of 0.5" in each. In addition, we detect several sources which correspond to cataloged NVSS sources. We note that the uncataloged source is at the detection threshold of NVSS. Further observations with the VLA are planned, and we urge optical observers to try to confirm this detection."
  This message may be cited.
• GCN notice #946
  GRB010213 Optical Observation
  J. Zhu, on behalf of the Beijing Astronomical Observatory GRB team, report:
  "The 58 x 58 arcmin area centered at the HETE II error circle of GRB010214 (G. Ricker et al, GCN #934) were imaged on Feb. 15.5 (48 hours after the burst) with the BAO 0.6-m Schmidt telescope. 13 images were taken (30 min. exposure for each) with the BATC-i filter, and the detection limitation of the combined image is about R=22.
  There is no optical counterpart at the position of the radio source mentioned by E. Berger and D. A. Frail (GCN #945) for our detection threshold. (An epoch 2000.0 is assumed for their coordinates.)
  The image will be compared with further observations for any variable object.
  This report may be cited."
  
• GCN notice #947
  D. A. Frail (NRAO) and E. Berger (Caltech) report on behalf of a larger collaboration:
  "On February 18.24 UT we conducted a second observation of the central region of the HETE II error circle of GRB010213 (GCN#934) with the VLA at 1.43 GHz. The weak radio source reported in GCN#945 is still present at approximately the same flux level (~1 mJy) as measured on February 15.42 UT. Furthermore, there is a weak (6-sigma) source present at this position in 1.4 GHz images taken as part of the FIRST survey (http://sundog.stsci.edu/top.html). We no longer consider this radio source to be a viable afterglow candidate."
  This message may be cited.