Fermi LAT detection of a GeV gamma-ray flare from blazar 4C +31.03 (B2 0110+31)
ATel #15841; Stefano Ciprini (INFN Roma Tor Vergata & ASI Space Science Data Center, Roma, Italy), Simone Garrappa (Ruhr-University Bochum; DESY, Germany), on behalf of the Fermi Large Area Telescope Collaboration
on 3 Jan 2023; 18:34 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@ssdc.asi.it)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar
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 4C +31.03, also known as B2 0110+31, OC 317, 4FGL J0112.8+3208 and 3FHL J0112.9+3208 (Abdollahi, et al. 2020, ApJS, 247, 33; Ajello et al. 2017, ApJS, 232, 18), with radio coordinates R.A. = 18.20972 deg, Dec. = 32.13818 deg (J2000; Beasley et al. 2002, ApJS, 141, 13), and redshift z=0.603 (Wills & Wills 1976, ApJS, 31, 143).
Preliminary analysis indicates that 4C +31.03 was in an elevated gamma-ray emission state during the past days, reaching a daily averaged gamma-ray flux (E>100MeV) of (1.2+/-0.2) X 10^-6 photons cm^-2 s^-1 and (4.3+/-0.3) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only) respectively on January 1 and January 2, 2023. These correspond to flux increases of a factor of up to about 60 with respect to the average flux reported in the fourth Fermi-LAT catalog (4FGL). The corresponding power-law photon indexes are 2.5+/-0.2 and 1.9+/-0.1 respectively, where the 4FGL value is 2.37+/-0.02. At least one photon of 51.3GeV energy is also spatially consistent with this blazar.
This is the second time that the Fermi LAT Collaboration has reported enhanced gamma-ray activity from 4C +31.03 after May 2009 (ATel#2054). This current new flare is also advertised by the FERMI-NOTICE #1672674483 .Â
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of 4C +31.03 will continue. A preliminary uncalibrated estimation of the daily gamma-ray flux observed by Fermi LAT is publicly available here , and this blazar source has also an entry in the FSSC light curve repository. We encourage multifrequency observations of this gamma-ray source. For this source, the Fermi-LAT contact persons are E. Cavazzuti (elisabetta.cavazzuti[at].asi.it) and S. Ciprini (stefano.ciprini[at]ssdc.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.
