Swift Follow-up of the New Gamma-ray Detection of TXS 1731+152A

ATel #6410; R. Ojha (NASA/GSFC/UMBC/CRESST), B. Carpenter (CUA/NASA/GSFC), F. Krauss (Remeis Observatory & ECAP, FAU Erlangen/Univ. Wuerzburg), J. Becerra (NASA/GSFC/UMCP/CRESST) on behalf of the Fermi LAT Collaboration.
on 22 Aug 2014; 14:49 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)

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Following the gamma-ray detection of the flat spectrum radio quasar TXS 1731+152A by Fermi/LAT on 2014 August 13 (ATel #6395), two Swift target of opportunity observations were performed on 2014 August 16 and 18.

Swift/XRT data were taken in Photon Counting mode. Due to the faintness of the source and because there was no sign of significant variation between the two epochs, we report results from combining the data from both epochs for a total exposure of about 7.1 ksec. The X-ray spectrum (0.5-10 keV) can be fit by an absorbed power law model with an HI column density set to the Galactic value of 6.48x10^20 cm^-2 (Kalberla et al. 2005, A&A, 440, 775) using the abundances of Wilms et al. (2000, ApJ, 542, 914) and the cross sections of Verner et al. (1996, ApJ, 465, 487). The unabsorbed observed flux was (4.3+-2.3)x10^-13 erg cm^-2 s^-1 with a photon index of 0.9+-0.5. No previous X-ray observations of this source exist in the literature. However, our count rate of 5.9x10-3 cps is about 4.5 times above the Swift XRT equivalent count rate calculated from the ROSAT sensitivity limit.

The source was not detected in simultaneous Swift/UVOT observations. Magnitude limits were obtained at all bands as listed below. No archival data are available for any of these bands.

Filter   Upper_Limit
V     >18.18
B     >18.66
U     >18.20
W1   >18.63
M2   >20.57
W2   >19.64

Further multiwavelength observations are encouraged. For this source the Fermi LAT contact person is Josefa Becerra (Josefa.Becerra@nasa.gov).

We would like to thank the Swift Team for making these observations possible, in particular C. Gronwall as the Swift Observatory Duty Scientist.