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GCN Circular 7874

Subject
GRB 080514B: Spectroscopic constraints and probable host galaxy
Date
2008-06-13T16:18:12Z (16 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, J. S. Bloom (UC Berkeley), H.-W. Chen (U Chicago), R. J. 
Foley, A. A. Miller, J. Shiode, J. Brewer, D. Starr, and R. Kennedy 
(UCB) report:

On the night of 2008-06-07 (UT) we observed the location of the 
Super-AGILE burst GRB 080514B (GCN 7715, Rapisarda et al.) with Keck I / 
LRIS in g and R filters for 1080s and 960s respectively, starting at 
12:53 UT.  We detect a source consistent with the afterglow position (de 
Ugarte Postigo et al., GCN 7719) in both filters.  Photometry within a 
1.1" radius aperture gives an magnitude (calibrated to three nearby USNO 
B1.0 stars) of:

R = 23.9 +/- 0.2 (t = 24.1 days)

Compared to the measurement of Malesani et al. (R = 22.52 at 1.77 days, 
GCN 7734), this would suggest a decay index of only about alpha = 0.5 
were this the GRB afterglow, which is unlikely at such late times.  More 
likely, the source represents a relatively bright host galaxy of this burst.

However, analysis of a 2x1200s Gemini-North spectrum using GMOS taken at 
the afterglow location (offset <0.5" from the host from a comparison 
from the Gemini i-band acquisition image) 1.9 days after the GRB shows 
no significant emission or absorption features over the usable spectral 
range from 4000-6720 Angstroms.  The continuum flux extends all the way 
to 4000 Angstroms without evidence of Lyman-alpha forest absorption, 
which imposes a redshift constraint of z < 2.3.  Further follow-up is 
encouraged.

A colorized image of the field is available at:

http://lyra.berkeley.edu/~dperley/080514b/080514b_color.png
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