Fermi LAT detection of renewed gamma-ray activity from PKS 2142-75
ATel #6157; Stefano Ciprini (ASI ASDC & INAF Rome), on behalf of the Fermi Large Area Telescope Collaboration
on 21 May 2014; 19:43 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@asdc.asi.it)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar, Transient
Referred to by ATel #: 6208
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed high-level gamma-ray activity from a source positionally consistent with the flat spectrum radio quasar PKS 2142-75 (R.A.: 326.80304 deg, Dec.: -75.60367 deg, J2000, Johnston et al. 1995, AJ, 110, 880). The redshift of this source is z=1.139 (Jauncey et al. 1978, ApJ, 219, L1).
Preliminary analysis indicates that on 2014 May 20 the daily averaged flux (E>100MeV) was (1.2 +/- 0.3) X 10^-6 photons cm^-2 s^-1 (errors are statistical only), about a factor of 10 greater than reported in the second Fermi LAT catalog (2FGL J2147.4-7534, Nolan et al. 2012, ApJS 199, 31).
Fermi-LAT already detected a gamma-ray flare from this object in April 2010 (ATel#2539 and Dutka et al. 2013, ApJ, 779, 174), reported also by AGILE (ATel#2551). Since Fermi operates in an all-sky scanning mode, regular monitoring of this source will continue. This source is one of the "LAT Monitored Sources" and consequently a preliminary estimation of the daily gamma-ray flux observed by Fermi LAT is publicly available (http://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/source/PKS_2142-75).
The Fermi LAT contact person for this source is Roopesh Ojha (roopesh.ojha@gmail.com). In consideration of the ongoing activity of this source we strongly encourage multiwavelength observations.
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.
