GCN Circular 7175
Subject
XRB 080109/SN 2008D:PAIRITEL NIR observations and t_0 from Swift
Event
Date
2008-01-13T03:42:47Z (19 years ago)
Edited On
2026-04-24T17:51:48Z (4 months ago)
From
Maryam Modjaz at UC Berkeley <mmodjaz@astro.berkeley.edu>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>
M. Modjaz, J. S. Bloom, N. R. Butler, D. Starr (UC Berkeley), R. P.
Kirshner, A. Friedman (Harvard/CfA) report on behalf of a larger
collaboration:
"From our analysis of the Swift XRT data we find an explosion time for the
start of XRB 080109 (Berger & Soderberg, GCN 7159; Kong & Marcone, ATEL
1355) as viewed by Swift of:
t_0 = 2008-01-09 13:32:49 UT (+/- 5 sec).
We observed the field of SN 2007uy (Nakano et al. IAUC 8908; Blondin et
al. CBET 1191) with the 1.3m PAIRITEL on Mt. Hopkins on 2008-01-09 08:45
UT, i.e. 4.5 hours before t_0. We started observing again on 2008-01-10
06:23:06 UT, i.e. 17 hours after the burst and for the following nights.
The SN 2008D (Li & Filippenko, IAUC 1202; Soderberg et al., GCN 7165;
Malesani et al., GCN 7169; Valenti et al., GCN 7171; Blondin et al., CBET
1205, see also GCN 7160-7168) associated with XRB 080109 is clearly
detected in mosaic-stacks of each ~1100-sec integration time. From
preliminary reductions of multi-epoch observations on Jan 11 and Jan 12,
using ~15-20 2MASS stars in the field for the zeropoint, we derive the
following error-weighted aperture magnitudes:
Filter midtime (UTC) Magnitude MagError
J 2008-01-11 8.4 16.63 0.13
H 2008-01-11 8.4 16.33 0.17
K_s 2008-01-11 8.3 16.11 0.18
J 2008-01-12 8.0 16.51 0.06
H 2008-01-12 7.9 16.15 0.14
K_s 2008-01-12 7.9 16.22 0.29
No strong variability is detected over those 2 nights but the source was
clearly not visible at these magnitudes on Jan 9 UT. Further data
reduction and observations are in progress. SN 2007uy was measured to be
~1 mag brighter in the J, H, K_s filters on Jan 11 and 12 UT."
A comparison of the 9 Jan, 12 Jan and historical 2MASS imaging can be
found at:"
http://pairitel.org/2sne-fig4.tiff