GCN Circular 7398
Subject
GRB 080310: Swift/UVOT Refined Analysis
Date
2008-03-10T18:15:23Z (16 years ago)
From
Erik Hoversten at Swift/Penn State <hoversten@astro.psu.edu>
E. A. Hoversten (PSU) and J. R. Cummings (NASA/UMBC) report on behalf
of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 080310 (trigger 305288)
starting 99 seconds after the BAT trigger (Cummings, et al., GCN
Circ. 7382) starting with a 100s finding chart exposure in the white
filter. A bright afterglow was clearly detected in the initial white
and V band exposures.
Further analysis shows that a fading source is detected at the XRT
position in the U, B, V, and white filter images. The source is
still detectable in these filters around 7000 seconds after the
burst. The white and U band images show a brightening of the source
reaching a peak after 1 ks after the burst before fading smoothly.
The B and V images show a more smooth decay.
The afterglow is not detected in the UVW1 and UVM2 filters and is
weakly detected in the UVW1 filter. This is consistent with the
measured redshift of 2.42 (Prochaska, et al., GCN Circ. 7388).
The detections and 3-sigma upper limits in the UVOT photometric
system (Poole, et al. 2008, MNRAS 383, 627) are given in the
following table. The white and optical magnitudes are individual
exposures while the UV magnitudes are from co-added images.
Filter T_start(s) T_stop(s) Exposure(s) Mag
white 99 197 98 18.50 +/- 0.06
white 868 967 98 17.95 +/- 0.05
white 6788 6985 197 18.99 +/- 0.07
v 208 602 393 17.38 +/- 0.05
v 7199 7334 135 18.5 +/- 0.3
b 685 695 10 17.7 +/- 0.2
b 6584 6780 197 18.9 +/- 0.1
u 660 680 19 17.8 +/- 0.2
u 1430 1450 19 17.3 +/- 0.2
u 6379 6575 197 18.3 +/- 0.1
uvw1 638 6373 452 20.3 +/- 0.3
uvm2 613 6168 197 >19.8
uvw2 716 7194 432 >20.8
No correction has been made for the expected Galactic extinction of E
(B-V) of 0.04 mag in the direction of the burst (Schlegel, et al. 1998).