Hard X-ray view of two $\gamma$-ray detected low-luminosity active galactic nuclei: NGC 315 and NGC 4261

Abstract

Aims. The accretion disk of low-luminosity active galactic nuclei (LLAGNs) is a radiatively inefficient accretion flow (RIAF). Our goal is to find evidence of RIAF radiation from LLAGNs with jets and analyze their radiation properties, which also adds samples to future research on LLAGNs. Methods. Weconducted an analysis of the X-ray data obtained from NuSTAR and XMM-Newton observations of NGC 315 and NGC 4261, encompassing both timing and spectral investigations. The joint X-ray spectra of the two LLAGNs were fitted using various functional forms and radiative models in XSPEC. Results. No significant variability on timescales of days is observed for both NGC 315 and NGC 4261. The X-ray continuum emission of NGC 315 is suitable for cutoff power-law (PL) fitting, yielding a cutoff energy of Ecut = 18.45 keV, which is the lowest value found in LLAGNssofar. In contrast, the X-ray continuum of NGC 4261 is composed of two PL components, with no signs of a cutoff energy. A prominent neutral Fe Kα line is observed in NGC 315, while an ionized Fe XXV line is seen in NGC 4261. The derived reflection fractions are R = 0.61 for NGC 315 and R = 0.18 for NGC 4579. Neither NGC 315 nor NGC 4261 shows evidence of a Compton reflection bump. Conclusions. The X-ray spectral characteristics support the RIAF emission as the dominant origin of the X-rays in both sources, although an additional soft PL component originating from the inner jet is observed in NGC 4261. The higher reflection fraction compared to other LLAGNs, along with the detection of a neutral Fe Kα line, suggests the existence of a truncated accretion disk with a relatively small radius in NGC 315. Bremsstrahlung radiation appears to be the dominant cooling mechanism for the plasma in NGC315, while Comptonization within the RIAF is more likely responsible for the X-ray emission in NGC 4261.

arXiv comment11 pages, 6 figures, 6 tables. Accepted for publication in A&A

References in corpus (57)

• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• Advection-Dominated Accretion: A Self-Similar Solution
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Hot Accretion Flows Around Black Holes
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• On characterising the variability properties of X-ray light curves from active galaxies
• Nuclear Activity in Nearby Galaxies
• Nonthermal Electrons in Radiatively Inefficient Accretion Flow Models of Sagittarius A*
• Statistics: Handle with Care, Detecting Multiple Model Components with the Likelihood Ratio Test
• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• Incremental Fermi Large Area Telescope Fourth Source Catalog
• An X-ray Spectral Model for Compton-Thick Toroidal Reprocessors
• A Search for "Dwarf" Seyfert Nuclei. IV. Nuclei with Broad H-alpha Emission
• The Spectral Energy Distributions of Low-Luminosity Active Galactic Nuclei
• Radio Sources in Low-Luminosity Active Galactic Nuclei.IV. Radio Luminosity Function, Importance of Jet Power, and Radio Properties of the Complete Palomar Sample
• Compact steep-spectrum and peaked-spectrum radio sources
• X-ray variability of 104 active galactic nuclei. XMM-Newton power-spectrum density profiles
• An X-ray view of 82 LINERs with Chandra and XMM-Newton data
• The Nature of the Compton-thick X-ray Reprocessor in NGC 4945
• X-ray Properties of LINERs and Low-luminosity Seyfert Galaxies Observed with ASCA. I. Observations and Results
• Chandra and XMM-Newton Observations of a Sample of Low-Redshift FRI and FRII Radio-Galaxy Nuclei
• The long term X-ray spectral variability of AGN
• Spectral Models for Low-luminosity Active Galactic Nuclei in LINERs: The Role of Advection-dominated Accretion and Jets
• BAT AGN Spectroscopic Survey -- XII. The relation between coronal properties of Active Galactic Nuclei and the Eddington ratio
• Correlation between the photon index and X-ray luminosity of black hole X-ray binaries and active galactic nuclei: observations and interpretation
• Radio Sources in Low-Luminosity Active Galactic Nuclei. I. VLA Detections of Compact, Flat-Spectrum Cores
• The anti-correlation between the hard X-ray photon index and the Eddington ratio in LLAGNs
• Evolution of the Nuclear Accretion Disk Emission in NGC 1097: Getting Closer to the Black Hole
• Testing Comptonization models using BeppoSAX observations of Seyfert 1 galaxies
• A NuSTAR census of coronal parameters in Seyfert galaxies
• Obscuration and Origin of Nuclear X-ray emission in FR I Radio Galaxies
• Study of LINER sources with broad H(alpha) emission. X-ray properties and comparision to luminous AGN and X-ray binaries
• Spectral Energy Distributions of Weak Active Galactic Nuclei Associated With Low-Ionization Nuclear Emission Regions
• A Thermal Bremsstrahlung Model For the Quiescent X-ray Emission from Sagittarius A*
• On the origin of X-ray emission in some FR Is: ADAF or jet?
• Thermodynamic properties, multiphase gas and AGN feedback in a large sample of giant ellipticals
• The Central Engines of 19 LINERs as Viewed by Chandra
• A comprehensive analysis of the hard X-ray spectra of bright Seyfert galaxies
• VLBA Imaging of NGC 4261: Symmetric Parsec-scale Jets and the Inner Accretion Region
• X-ray spectral variability of seven LINER nuclei with XMM-Newton and Chandra data
• The X-ray jet and central structure of the active galaxy NGC 315
• The inner jet of radio galaxy NGC 315 as observed with Chandra and the VLA
• A Parsec Scale Accelerating Radio Jet in the Giant Radio Galaxy NGC315
• On the origin of the X-rays and the nature of accretion in NGC 4261
• X-ray spectral variability of LINERs selected from the Palomar sample
• NuSTAR Hard X-ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk
• Suzaku Observations of gamma-Ray Bright Radio Galaxies: Origin of the X-ray Emission and Broad-Band Modelin
• Orientation and Speed of the Parsec-Scale Jet in NGC4261 (3C270)
• The XMM-Newton View of the Nucleus of NGC 4261
• Chandra Survey of Nearby Galaxies: Testing the Accretion Model for Low-luminosity AGNs
• Direct Evidence from Spitzer for a low-luminosity AGN at the center of the Elliptical Galaxy NGC 315
• Constraining the X-ray reflection in low accretion rate AGN using XMM-Newton, NuSTAR and Swift
• The absence of a thin disc in M81
• Coronal Properties of Low-Accreting AGNs using Swift, XMM-Newton and NuSTAR Observations
• Broadband Modeling of Low Luminosity Active Galactic Nuclei Detected in Gamma Rays
• Investigating disc-corona interaction in axisymmetric accretion disc models

Cited by in corpus (1)

• Nuclear Activity and Host Galaxy Properties of Low-Luminosity AGN Identified from VLA Observations