TITLE:   GCN CIRCULAR
NUMBER:  5982
SUBJECT: GRB 050826: MDM Redshift
DATE:    06/12/25 04:34:34 GMT
FROM:    Jules Halpern at Columbia U.  <jules@astro.columbia.edu>

J. P. Halpern & N. Mirabal (Columbia U.) report on behalf of the
MDM Observatory GRB follow-up team:

"Previously, we reported the detection of the optical afterglow of
Swift GRB 050826 within a relatively bright, irregular galaxy of
R=21.67, or R=20.1 when corrected for Galactic extinction.
Image subtraction was used to separate the OT contribution
from the host galaxy. See GCNs 3891 and 4749 for details.

On 2006 Dec. 24 UT, we obtained three 1-hour, low-resolution spectra
of the host galaxy using the Boller & Chivens CCD Spectrograph (CCDS)
on the MDM 2.4m telescope.  Acquisition was by blind offset. Narrow
emission lines corresponding to [O II] 3727 and [O III] 4959,5007
are seen in the individual exposures.  Their line strengths are
characteristic of a high-excitation starburst, similar to other
hosts of long bursts.  From the summed spectrum, we derive a redshift
of z=0.297+/-0.001.

The Swift BAT fluence of 4.3x10^-7 erg/cm^2 in the 15-150 keV band
(Markwardt et al., GCN 3888) then corresponds to an isotropic
energy release of 9x10^49 erg using standard cosmological parameters.
This example illustrates the role of image subtraction in completing
the census of low-luminosity GRBs in nearby galaxies.

This message may be cited."