GCN Circular 21000
Subject
GRB170405A, Swift-UVOT Detection
Event
Date
2017-04-07T06:46:05Z (9 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 170405A: Swift/UVOT Detection
S. J. LaPorte (PSU) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170405A
129 s after the BAT trigger (Troja et al., GCN Circ. 20984). Consistent
with previous reports (Malesani et al, GCN Circ. 20988; Martin-Carrillo et al.
GCN Circ. 20991), a fading source consistent with the XRT position
(Evans et al. GCN Circ. 20985) is detected in the initial UVOT exposures at:
RA (J2000) = 14:39:18.73 = 219.82805 (deg.)
Dec (J2000) = -25:14:35.4 = -25.24317 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
The upper limits in the UV bands are consistent with the reported
redshift of z = 3.51 (de Ugarte-Postigo et al, GCN Circ. 20990).
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 (fc) 129 279 147 16.01 +/- 0.03
white 747 998 143 18.09 +/- 0.07
v 618 637 20 16.31 +/- 0.14
b 543 563 20 17.34 +/- 0.13
u 287 711 265 >20.2
uvw1 667 859 39 >18.9
uvm2 815 835 19 >17.5
uvw2 593 786 39 >19.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).