GCN Circular 9758
Subject
GRB090809: Swift/UVOT observations
Date
2009-08-10T05:37:54Z (15 years ago)
From
Wayne Landsman at GSFC/SSAI <wayne.b.landsman@nasa.gov>
W.B. Landsman (NASA/GSFC) and C. Markwardt (CRESST/GSFC/UMD) report on
behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090809
108s after the BAT trigger (Markwardt et al., GCN Circ. 9754), The
tentative UVOT detection reported by Markwardt et al. is confirmed
following the downlink of additional data. The UVOT position
determined from the white finding chart exposure is
RA (J2000) 21:54:43.19 = 328.679938 (deg)
Dec (J2000) -00:05:1.83 = -0.083842 (deg)
with an estimated uncertainty of 0.6 arcsec (radius, 90% confidence,
statistical + systematic), consistent with the NOT afterglow position
(Xu et al., GCN Circ. 9755).
The initial magnitudes and upper limits are as follows:
Filter T_start(s) Tstop(s) Exp(s) Mag
white 108 194 84 19.53 +/- 0.14
white 3396 3545 147 21.03 +/- 0.33
v 3552 5181 393 19.87 +/- 0.30
b 4365 5976 367 >21.1 (3 sigma)
u 4162 5796 391 >20.8 (3 sigma)
uvw1 3962 5592 393 >20.7 (3 sigma)
uvm2 3757 5386 393 >20.5 (3 sigma)
uvw2 4776 10964 1082 >21.6 (3 sigma)
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.10 in the direction of the burst
(Schlegel et al. 1998). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).