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TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1924 SUBJECT: Chandra detection of the X-ray afterglow of GRB 030226 DATE: 03/03/05 11:49:59 GMT FROM: Jens Hjorth at U.Copenhagen <jens@astro.ku.dk> Kristian Pedersen (U. of Copenhagen), Johan Fynbo (U. of Aarhus), Jens Hjorth (U. of Copenhagen), Darach Watson (U. of Copenhagen) report on behalf of the GRACE collaboration: "Chandra X-ray Observatory observed the field of the GRB 030226 (Suzuki et al., GCN 1888) with the ACIS-S3 detector for a total of 11.9 hours, starting Feb 27, 16:49 UT, 37.1 hours after the GRB trigger. Based on a preliminary analysis we identify a previously unknown, fading X-ray source at the position RA (J2000.0) = 11 33 04.93, Dec (J2000.0) = +25 53 55.3 consistent with the position of the optical transient (Price et al., GCN 1880). The positional accuracy is better than one arcsec. Hence we identify the source as the X-ray afterglow of GRB 030226. The 0.3-10 keV count rate averaged over the observation is 9.7e-03 counts/s, and the average 2-10 keV flux is 3.2e-14 erg/cm^2/s. The spectrum is well fitted by an absorbed power law with spectral index 1.0 +/-0.2, absorption fixed at the Galactic value (1.6e20 cm^2), and an absorbing column density of 1e22 +/- 0.5e22 cm^-2 at a redshift of 1.98. A power law with Galactic absorption only is not an acceptable fit to the soft part of the Chandra spectrum. No other obvious spectral features are detected. We thank Harvey Tananbaum for rapidly approving Director's Discretionary Time for this observation, and the staff at the Chandra Science Center for smoothly implementing and processing the observation."
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