Fermi LAT detection of increasing gamma-ray activity from flat spectrum radio source PMN J1913-3630
ATel #16033; Federica Giacchino (INFN Sezione Roma TorVergata & ASI Science Data Center, Italy), Denis Bernard (LLR, Ecole Polytechnique & CNRS/IN2P3), Janeth Valverde (UMBC & NASA / GSFC) and Jordan Forman (SURA & NASA/GSFC) on behalf of the Fermi Large Area Telescope Collaboration
on 10 May 2023; 17:31 UT
Credential Certification: Federica Giacchino (federica.giacchino@roma2.infn.it)
Subjects: Gamma Ray, >GeV, 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 source PMN J1913-3630, also known as 4FGL J1913.4-3629 (Abdollahi et al. 2022, ApJS, 260, 53) and VCS4 J1913-3630, with VLBI coordinates (J2000.0) R.A.: 288.33704 deg., Dec: -36.50538 deg. (L. Petrov et al. 2006 AJ 131, 1872). The source has no known redshift.
Preliminary dedicated analysis indicates that on May 7, 2023, PMN J1913-3630 reached a daily gamma-ray flux (E>100MeV) of (1.08+/- 0.25) x 10^-6 photons cm^-2 s^-1 (statistical uncertainty only), about 130 times greater than the average flux reported in the four Fermi-LAT catalog (4FGL, Abdollahi et al. 2020, ApJS, 247, 33) and representing a renewed and active phase after October 2010 (ATel #2966). The corresponding photon index (2.02 +/- 0.15) and is 0.3 smaller than the 4FGL-DR3 value, indicating a slightly harder state.
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. The blazar PMN J1913-3630 is one of the "LAT Monitored Sourcesâ (https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source.html?source_name=4FGL_J1913.4-3629). For this source the Fermi LAT contact persons are Denis Bernard (denis.bernard@in2p3.fr) and Federica Giacchino (federica.giacchino@roma2.infn.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.
