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GCN Circular 10913

Subject
GRB 100213B: Detection of Fading Optical Afterglow
Date
2010-06-30T23:03:00Z (14 years ago)
From
Jules Halpern at Columbia U. <jules@astro.columbia.edu>
Y. Li, J. Weston, X. Fernandez, A. Brown, J. H. Yoon, A. P. S. Crotts,
and J. P. Halpern (Columbia U.) report on behalf of the graduate
Observational Astronomy class:

"We obtained R-band images of the field of Swift GRB 100213B (Vetere et al.,
GCN 10412Not found
 
 
) on two consecutive, photometric nights using the MDM 1.3m
telescope, for total exposure times of 30 and 40 minutes, respectively.
Within 3.8" of the enhanced Swift XRT afterglow position (of 90% confidence
radius 3.5", Evans, GCN 10423Not found
 
 
), we find a fading object at

      (J2000) R.A. = 08h 17m 07.94s, Decl. = +43d 26' 54.94"

with positional uncertainty ~0.5", and the following magnitudes:

    ----------------------------------------------------------
     Date(UT)  Mid-time(UT) t-t0(hr)  Exp(min)      R(mag)
    ----------------------------------------------------------
     Feb. 14      03:44        4.8       30      22.00+/-0.14
     Feb. 15      03:35       28.6       40      23.01+/-0.24
    ----------------------------------------------------------

Magnitudes are referenced to Landolt (1992) standard stars, and are not
corrected for Galactic extinction.

The position of the afterglow coincides with the R ~ 21.5 object detected by
Malesani et al. (GCN 10413Not found
 
 
) 19 minutes after the GRB, and whose redshift
z = 0.604 was measured by Cucchiara et al. (GCN 10422Not found
 
 
). We conclude that the
observed variability and positional coincidence with an emission-line object
establishes the optical afterglow and host galaxy redshift of GRB 100213B.
Further observations of the host galaxy are encouraged.

MDM images of the field are posted at

http://www.astro.columbia.edu/~jules/grb/100213b/

This message may be cited."