IGR J18249-3243: a new GeV-emitting FR II and the emerging population of high energy radio galaxies

Abstract

The advent of new all-sky radio surveys such as the VLA Sky Survey (VLASS) and the Rapid ASKAP Continuum Survey (RACS), performed with the latest generation radio telescopes, is opening new possibilities on the classification and study of extragalactic $\gamma$-ray sources, specially the underrepresented ones like radio galaxies. In particular, the enhanced sensitivity (sub-mJy level) and resolution (a few arcsec) provides a better morphological and spectral classification. In this work, we present the reclassification of a Fermi-LAT source as a new FRII radio galaxy from the INTEGRAL sample found to emit at GeV energies. Through a broad-band spectral fitting from radio to $\gamma$-ray, we find that the commonly invoked jet contribution is not sufficient to account for the observed $\gamma$-ray flux. Our modeling suggests that the observed emission could mainly originate in the lobes (rather than in the radio core) by inverse Compton scattering of radio-emitting electrons off the ambient photon fields. In addition, we cross-correlated the latest generation radio surveys with a list of Fermi-LAT objects from the literature considered to be candidate misaligned AGN, finding four new radio galaxies with a double-lobed morphology. Additional four objects could be classified as such thanks to previous studies in the literature, for a total of nine new radio galaxies with GeV emission presented in this work. We foresee that further objects of this class might be found in the near future with the advent of the Square Kilometer Array (SKA), populating the GeV sky.

Submitted to MNRAS

References in corpus (26)

• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• BAT AGN Spectroscopic Survey - V. X-ray properties of the Swift/BAT 70-month AGN catalog
• The LOFAR Two-metre Sky Survey -- V. Second data release
• The 3rd IBIS/ISGRI soft gamma-ray survey catalog
• The Rapid ASKAP Continuum Survey I: Design and First Results
• Fermi Gamma-ray Imaging of a Radio Galaxy
• SkyMapper Southern Survey: Second Data Release (DR2)
• Compact steep-spectrum and peaked-spectrum radio sources
• The extragalactic background light revisited and the cosmic photon-photon opacity
• A pilot study of the radio-emitting AGN population: the emerging new class of FR0 radio-galaxies
• Planetary nebulae as tracers of galaxy stellar populations
• The multiwavelength variability of 3C 273
• Unveiling the nature of INTEGRAL objects through optical spectroscopy. VI. A multi-observatory identification campaign
• Unveiling the nature of INTEGRAL objects through optical spectroscopy. VII. Identification of 20 Galactic and extragalactic hard X-ray sources
• Hydrodynamical Backflow in X-shaped Radio Galaxy PKS 2014-55
• Swift-XRT observation of 34 new INTEGRAL/IBIS AGNs: discovery of Compton thick and other peculiar sources
• Modelling of the Spectral Energy Distribution of Fornax A: Leptonic and Hadronic Production of High Energy Emission from the Radio Lobes
• NGC 3894: a young radio galaxy seen by Fermi-LAT
• Gamma-rays from young radio galaxies and quasars
• Correlation between X-ray and radio absorption in compact radio galaxies
• The Extragalactic Gamma-Ray Background from Core Dominated Radio Galaxies
• The AGN nature of three INTEGRAL sources: IGR J18249-3243, IGR J19443+2117 and IGR J22292+6647
• Optical spectroscopic observations of low-energy counterparts of Fermi-LAT gamma-ray sources
• Nonthermal emission in the lobes of Fornax A
• Revisiting the TeV detection prospects for radio galaxies
• Non-thermal emission in lobes of radio galaxies: III. 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236