Swift Follow-up of the recent Gamma-ray flare of the FSRQ PKS B1035-281
ATel #8767; Bryce Carpenter (CUA/NASA/GSFC) and Roopesh Ojha (NASA/GSFC/UMBC) on behalf of the Fermi Large Area Telescope Collaboration
on 3 Mar 2016; 19:36 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Optical, Ultra-Violet, X-ray, Gamma Ray, >GeV, AGN, Blazar, Quasar
Referred to by ATel #: 8780
Following a recent gamma-ray flare of the flat spectrum radio quasar PKS B1035-281 (ATel#8740), two Swift target of opportunity observations were performed on 2016 February 26 and March 2.
Swift/XRT data were taken in Photon Counting mode for a total exposure of about 4.7 ksec and 4.0 ksec, respectively. 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 4.40x10^20 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 observed fluxes are (7.6+-2.0)x10^-13 and (1.2+-0.32)x10^-12 erg cm^-2 s^-1; while the photon indexes are 1.9+-0.4 and 1.7+-0.4, respectively. This represents an increase in the flux compared to that observed during a gamma-ray quiet state on
2010 January 21, (6.1+-3.3)x10^-13 erg cm^-2 s^-1. The photon index during that epoch was 1.1+-0.6.
Simultaneous Swift/UVOT observations are shown below, along with magnitudes from archival observations on 2009 August 10 and 2010 January 21. The source was brighter than the archival values (where they are available) and has faded in all UVOT bands in the latter epoch.
| Filter |
2009-08-10 (mag) |
2010-01-21 (mag) |
2016-02-26 (mag) |
2016-03-02 (mag) |
V |
|
|
17.10+/-0.20 |
17.38+/-0.36 |
| B |
|
|
17.66+/-0.18 |
17.93+/-0.10 |
| U |
|
|
16.71+/-0.10 |
17.02+/-0.08 |
| W1 |
|
|
16.98+/-0.12 |
17.13+/-0.09 |
| M2 |
|
17.76+/-0.11 |
17.02+/-0.07 |
|
| W2 |
18.98+/-0.20 |
|
17.24+/-0.10 |
17.40+/-0.08 |
Further multiwavelength observations are encouraged. For this source the Fermi LAT contact person is B. Carpenter (carpbr01@gmail.com). We would like to thank the Swift Team for making these observations possible, in particular K. L. Page and B. Sbarufatti as the Swift Observatory Duty Scientists.
