Fermi-LAT detection of enhanced gamma-ray emission from CTA 102
ATel #6631; Sara Cutini (ASDC/INAF-OAR) on behalf of Fermi-LAT collaboration
on 28 Oct 2014; 10:11 UT
Credential Certification: Dario Gasparrini (dario.gasparrini@asdc.asi.it)
Subjects: Gamma Ray, >GeV, Request for Observations, Blazar
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed gamma-ray flaring activity from a source positionally consistent with the flat spectrum radio quasar CTA 102 (also known as 2FGL J2232.4+1143, Nolan et al. 2012, ApJS, 199, 31) with VLBI coordinates (J2000.0) R.A.: 22h 32m 36.4089s, Dec. +11d 43m 50.904s (Johnston et al. 1995, AJ, 110, 880).This gamma-ray blazar detected previously by COMPTEL (Blom et al. 1995, A&A, 295, 330) and EGRET (Nolan et al. 1993, ApJ, 414, 82), has redshift z=1.037 (Schmidt 1965, ApJ, 141, 1295).
Preliminary analysis indicates that CTA 102 was in a flaring state during all the week of 2014 October 20-26, reaching the maximum flux on October 24 and 25 with an average daily gamma-ray flux (E>100MeV) of (2.6 +/- 0.6) x 10^-6 photons cm^-2 s^-1 (statistical uncertainty only), about 30 times greater than the average flux reported in the second Fermi-LAT catalog.
Fermi-LAT already detected enhanced gamma-ray activity from this object in April 2011 (ATel #3320) and September 2012 (ATel #4397 and ATel #4409). CTA 102 is one of the "LAT Monitored Sources", and consequently, a preliminary, uncalibrated estimation of the daily gamma-ray flux observed by Fermi LAT is publicly available at: http://fermi.gsfc.nasa.gov/FTP/glast/data/lat/catalogs/asp/current/lightcurves/CTA102_86400.png
Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing activity of this source we encourage multiwavelength observations. For this source the Fermi LAT contact person is S. Cutini (sara.cutini@asdc.asi.it).
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.
