SWIFT observation of the Tidal Disruption candidate LSQ12heq
ATel #4739; E. Hadjiyska (Yale), B. P. Miller (University of Michigan), R. C. Reis (University of Michigan)
on 17 Jan 2013; 02:57 UT
Credential Certification: Ellie Hadjiyska (ellie.hadjiyska@yale.edu)
Subjects: Ultra-Violet, X-ray, AGN, Black Hole, Supernovae, Transient
We report on 4 consecutive SWIFT UVOT+XRT ToO observations of the initially assumed tidal disruption candidate LSQ12heq (ATel # 4644) commencing on 2012 Dec 18.
The UVOT magnitudes (background subtracted, uncorrected for the host galaxy) obtained are, as follows:
AB magnitudes with statistical errors (sys <= 0.03)
|
Obs 1 |
|
Obs 2 |
|
Obs 3 |
|
Obs 4 |
|
Filter |
mag |
err |
mag |
err |
mag |
err |
mag |
err |
V |
>19.75 |
|
19.03 |
0.27 |
19.64 |
0.4 |
19.21 |
0.30 |
B |
19.01 |
0.13 |
19.32 |
0.17 |
19.33 |
0.17 |
19.57 |
0.29 |
U |
19.33 |
0.12 |
19.42 |
0.14 |
19.48 |
0.14 |
19.60 |
0.15 |
W1 |
19.68 |
0.12 |
19.79 |
0.13 |
19.68 |
0.12 |
20.11 |
0.15 |
W2 |
20.19 |
0.11 |
20.14 |
0.11 |
20.33 |
0.12 |
20.39 |
0.13 |
LSQ12heq demonstrates excess UV flux from its host, GALEX J033304.1-281248 which has FUV and NUV magnitudes of 23.2 and 22.4 respectively.
The 3.7 ks stacked 0.3-10 keV image does not show any obvious X-ray counterpart. There are 5 counts within an r=30" aperture centered at the UV position (some likely from an unrelated source ~50" south). The PSF-corrected 95% confidence upper limit on the unabsorbed flux, assuming a Gamma=2 powerlaw, is 8.8e-14 erg/cm2/s which corresponds to Lx < 5e42 for z=0.15.
We thank the Swift team for having performed this observation.