[AAVSO-HEN] GRB 080721: Swift/UVOT Photometric Redshift

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  7991
SUBJECT: GRB 080721: Swift/UVOT Photometric Redshift
DATE:    08/07/21 15:05:46 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland at milkyway.gsfc.nasa.gov>

S. T. Holland, P. A. Ward (MSSL-UCL), and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT Team:

Preliminary UVOT photometry of the afterglow of GRB 080721 (Marshall,
et al. 2008, GCN Circ. 7988) shows that the afterglow is strongly
detected in the U band, but not in the UVW1, UVM2, or UVW2 bands at
approximately 825 s after the BAT trigger.  This suggests that the
redshift of GRB 080721 may be greater than approximately 2.3.