Swift Follow-up of the Gamma-ray Detection of 4C +50.11
ATel #5878; Felicia Krauss (Remeis Observatory & ECAP, FAU Erlangen/Univ. Wuerzburg), Bryce Carpenter (CUA/NASA/GSFC), Roopesh Ojha (NASA/GSFC/UMBC/CRESST), Matthias Kadler (Univ. Wuerzburg) on behalf of the Fermi/LAT Collaboration and Joern Wilms (Remeis Observatory & ECAP, FAU Erlangen)
on 11 Feb 2014; 21:38 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Ultra-Violet, X-ray, Gamma Ray, >GeV, AGN, Black Hole, Blazar, Quasar
Following the gamma-ray flaring activity of the FSRQ 4C +50.11 (also known as NRAO 150)
detected by Fermi/LAT on 2014 January 29 (ATel #5838), a Swift target of opportunity
observation was performed on February 2.
Swift/XRT data were taken in Photon Counting mode for a total exposure of about 4.5 ksec.
The X-ray spectrum (2-10 keV) can be fit by an absorbed power law model with an HI
column density of N_H = (2.5+/-0.9) x 10^22 cm^-2 and a photon index of 1.7+/-0.5 using
the abundances of Wilms et al. (2000, ApJ, 542, 914) and the cross sections of Verner et al.
(1996, ApJ, 465, 487). Note that the H column density is not consistent with the Galactic
HI value. The excess column density is most likely related to the complex environment in
the Galactic plane (b=-1.6 deg), e.g., dense molecular clouds (see e.g. Marscher,
Moore, & Bania, 1993, ApJ 419, L101) or an ionized component. The corresponding observed
2-10 keV flux is (0.59+/-0.11) x10^-11 erg cm^-2 s^-1. This absorbed flux is slightly
higher than that observed by Swift/XRT on 2010 November 7,
(0.36+/-0.13) x10^-11 erg cm^-2 s^-1.
Simultaneous Swift/UVOT observations on 2014 February 2 with the M2 filter did not
find a significant detection and established an upper limit of 20.66 mag (Vega system).
In consideration of the ongoing activity of this source, confirmed also by the Swift
observations, we encourage further multiwavelength observations. For this source the
Fermi/LAT contact person is Bryce Carpenter (carpbr01@gmail.com).
We would like to thank the Swift Team for making these observations possible,
in particular B. Sbarufatti as Swift Observatory Duty Scientist.
