[vsnet-grb-info 17789] GRB 160325A: Further Swift/UVOT Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19231
SUBJECT: GRB 160325A: Further Swift/UVOT Observations
DATE:    16/03/25 22:40:00 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen at gmail.com>

L. M. Z. Hagen (PSU) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

We report further on the Swift/UVOT observations of GRB 160325A which
began 75 s after the BAT trigger (Sonbas et al., GCN Circ. 19222). A
source was reported earlier by McCauley et al. (GCN Circ. 19228), which
was consistent with the XRT position (Evans et al., GCN Circ. 19229)
and infrared detection (Fugazza et al., GCN Circ. 19223).  We confirm
that the source is rapidly fading.

Preliminary detections and 3-sigma upper limits using the UVOT
photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               75          224          146         15.65+-0.05
white              567         1187          205         17.24+-0.05
white             7227        12203          231         19.59+-0.16
v                  617          809           38         15.12+-0.07
v                 1044         1237           38         15.79+-0.10
v                 1392         6402          216         17.73+-0.14
b                  543          735           38         17.11+-0.11
b                 1143         1510           58         18.70+-0.33
b                 7023         7222          196        >19.64
u                  287          537          245         18.91+-0.22
u                  691         7017          274        >19.47
uvw1               666         1461           97         18.36+-0.32
uvw1              6613         6812          196         19.05+-0.33
uvm2               641         1263           77         18.30+-0.34
uvm2              1416         6607          216         18.73+-0.29
uvw2               593         1387           97        >18.63
uvw2              5998         6197          196         18.30+-0.19

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).