Fermi-LAT Detection of a Hard Spectrum and Enhanced Gamma-ray Emission from the Blazar PMN J2052-5533
ATel #8096; Bryce Carpenter (CUA/NASA/GSFC), Jeff Magill (UMCP/NASA/GSFC) and Roopesh Ojha (NASA/GSFC/UMBC) on behalf of the Fermi Large Area Telescope Collaboration
on 25 Sep 2015; 15:13 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar
The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space
Telescope has observed an unusually hard spectrum gamma-ray flare from a source positionally consistent with
the blazar PMN J2052-5533 (3FGL J2051.8-5535; Acero et al. 2015, ApJS
218, 23), with coordinates RA: 20h52m13.68s, Dec: -55d33m10.0s, J2000,
(Healey et al. 2007, ApJS, 171, 61). There is no redshift reported for
this source in the literature.
Preliminary analysis indicates that on 23 September 2015 this source
was in a high-flux state, with a daily averaged gamma-ray flux (E>100MeV) of
(0.3+/-0.1) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only)
corresponding to a flux increase of a factor of about 16 with respect
to the four-year average flux of 3FGL J2051.8-5535. The corresponding photon spectral index (E>100MeV) of
1.6+/-0.2 is considerably harder than the average index of 2.5+/-0.2 for the 3FGL source.
Because Fermi operates in an all-sky scanning mode, regular gamma-ray
monitoring of this source will continue. We encourage further
multifrequency observations of this source. For this source the Fermi
LAT contact person is Bryce Carpenter (firstname.lastname@example.org).
The Fermi LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product of
an international collaboration between NASA and DOE in the U.S. and
many scientific institutions across France, Italy, Japan and Sweden.