Swift Follow-up of the Gamma-ray Flare in PKS 2142-75
ATel #6208; F. Krauss (Remeis Observatory & ECAP, FAU Erlangen/Univ. Wuerzburg), S. Ciprini (ASI ASDC & INAF Rome), R. Ojha (NASA/GSFC/UMBC/CRESST), M. Kadler (Univ. Wuerzburg) on behalf of the Fermi/LAT Collaboration
on 7 Jun 2014; 14:41 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Optical, Ultra-Violet, X-ray, Gamma Ray, >GeV, AGN, Black Hole, Blazar, Quasar
Following the gamma-ray flaring activity of PKS 2142-75 detected
by Fermi/LAT on 2014 May 20 (ATel #6157), two Swift target of
opportunity observations were performed on 2014 May 21 and 2014 May
24. As no significant differences were found between the two epochs
the combined results are reported here.
Swift/XRT data were taken in Photon Counting mode for a total exposure
of about 7.6 ksec. The X-ray spectrum (2-10 keV) can be fit by an
absorbed power law model with the HI column density set to the
Galactic value of 6.55x10^20 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 corresponding
observed 0.3-10 keV flux is (3.1+0.5/-0.4) x10^{-12} erg cm^-2 s^-1.
This absorbed flux is consistent with the flux of (3.4±0.6) x10^-{12}
reported in Dutka et al. 2013, ApJ, 779, 174 when this source was in a
gamma-ray quiescent state.
Simultaneous Swift/UVOT observations (shown in left column) show no
change in flux density (which has been obtained using the uvotsource tool)
compared to the values reported for the gamma-ray quiescent state by Dutka
et al. (shown in right column; V and B bands were not observed by
Dutka et al. 2013).
Units are in 10^-{12} erg/s/cm^2.
V: 2.68 ± 0.14
B: 2.53 ± 0.07
U: 2.33 ± 0.07 2.38 ± 0.08
W1: 1.67 ± 0.07 1.78 ± 0.06
M2: 0.94 ± 0.06 1.06 ± 0.08
W2: 0.54 ± 0.03 0.64 ± 0.05
Further multiwavelength observations are encouraged. For this source
the Fermi LAT contact person is Roopesh Ojha (Roopesh.Ojha@gmail.com).
We would like to thank the Swift Team for making these observations
possible, in particular M. H. Siegel as the Swift Observatory Duty
Scientist.
