[vsnet-grb-info 6604] GRB 080905B: Photometric Redshift for the 2MASS Galaxy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8210
SUBJECT: GRB 080905B: Photometric Redshift for the 2MASS Galaxy
DATE:    08/09/10 13:45:38 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland at milkyway.gsfc.nasa.gov>

Stephen Holland (CRESST/USRA/GSFC) reports, on behalf of the
Swift/UVOT team:

      We have performed UVOT photometry on the 2MASS galaxy 2MASX
J20065732-6233465 galaxy located 4 arcsec from the optical afterglow
of GRB 080905B (Stroh et al., 2008, GCNC 8182).  Our magnitudes are:

Filter    Mag  Err
    v    17.85 0.05
    b    18.70 0.05
    u    18.46 0.05
  uvw1   18.76 0.07
  uvm2   18.71 0.07
  uvw2   18.76 0.07

These magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.05 mag (Schlegel et al.,
1998, ApJS, 500, 525) along this line of sight.  The photometry is on
the UVOT photometric system described in Poole et al. (2008, MNRAS,
383,627).

      The detection in the uvw2 filter implies that the redshift of the
2MASS galaxy can not be greater than approximately z = 1.7.    This is
inconsistent with the VLT redshift of z = 2.374 for the afterglow
(Vreeswijk, et al., 2008, GCNC 8191).  This suggests that the 2MASS
galaxy is not the host galaxy of GRB 080905B.