[vsnet-grb-info 4208] GRB 070110: UVOT Observations of a Candidate Afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6009
SUBJECT: GRB 070110: UVOT Observations of a Candidate Afterglow
DATE:    07/01/11 00:29:04 GMT
FROM:    Pete Roming at PSU  <roming at astro.psu.edu>

P. Roming (PSU), P. T. Boyd, and H. Krimm (NASA/GSFC) report on behalf of 
the Swift UVOT team:

The Swift/UVOT began settled observations of GRB 070110 104 seconds after 
the BAT trigger (Krimm et al., GCN Circ.6005). Analysis of the merged 
Swift/UVOT data obtained on 2007-01-10 shows that the candidate optical 
afterglow was detected in the White, V, B, and U filters, but not in the UV 
filters. The photometry results are given for the 7 UVOT filters below:

Filter	   Tstart    Tstop    Exp       Mag    Error    Significance
White   104        5882     590	     20.0    0.14     9.1
V           210        23205   2065   20.3    0.20     5.7
B           4046     29593   1568   20.9    0.17     7.1
U           5274     35376   3166   20.4    0.10     11.6
UVW1   5069     34757   3758   20.8 (3-sigma UL)
UVM2    4864     33850   2739   21.1 (3-sigma UL)
UVW2   4456     39315   1853   20.9 (3-sigma UL)

There is marginal evidence for fading of the optical candidate but 
confirmation of its fading is pending further analysis. The values quoted 
above are not corrected for the expected extinction corresponding to E(B-V) 
of 0.014.