Fermi LAT detection of enhanced gamma-ray activity from the FSRQ B2 0202+31
ATel #12655; Stefano Ciprini (INFN Roma Tor Vergata and ASI Space Science Data Center, Roma, Italy), Chi C. Cheung (Naval Research Laboratory, Space Science Division, Washington, D. C., USA), on behalf of the Fermi Large Area Telescope Collaboration
on 12 Apr 2019; 08:08 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@ssdc.asi.it)
Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar, Transient
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed enhanced gamma-ray flaring activity from a source positionally consistent with the flat-spectrum radio quasar B2 0202+31, also known as TXS 0202+319, MG3 J020504+3212 and 4FGL J0205.2+3212 (The Fermi LAT collaboration 2019, arXiv:1902.10045), with coordinates R.A. = 31.270522 deg, Dec. = +32.208360 deg (J2000; Johnston et al. 1995 AJ 110, 880), and redshift z=1.466 (Burbidge 1970 ApJ 160, L33).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on 2019 April 10, with a daily averaged gamma-ray flux (E>100MeV) of (0.9 +/- 0.2) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). The latter corresponds to a flux increase of a factor of ~30 relative to the average flux reported in the fourth Fermi LAT source catalog (4FGL). The corresponding photon index is 2.4 +/- 0.2, similar to the 4FGL value of 2.67 +/- 0.05. This is the first time that an increasing gamma-ray flux trend for B2 0202+31 is announced with a telegram by the Fermi LAT Collaboration after more than 10 years of Fermi LAT all-sky survey observations.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is S. Ciprini (stefano.ciprini@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.
