Intrinsic absorption in 3C 279 at GeV-TeV energies and consequences for estimates of the EBL

Abstract

We revisit the limits of the level of the extragalactic background light (EBL) recently reported by the MAGIC collaboration based on the observed gamma-ray spectrum of the quasar 3C279, considering the impact of absorption of high-energy gamma-ray photons inside the broad line region (BLR) of the quasar. We use the photoionization code CLOUDY to calculate the expected optical-UV radiation field inside the BLR and the optical depth to gamma-rays for a relatively extended set of the parameters. We found that the absorption of gamma-ray photons, though important for the estimate of the true radiative output of the source, does not produce an important hardening of the spectrum of 3C279 in the energy band accessible by MAGIC, supporting the method used to infer the upper limits to the level of the EBL.

5 pages, 4 figures, accepted for publication in MNRAS

References in corpus (9)

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• MAGIC upper limits to the VHE gamma-ray flux of 3C454.3 in high emission state
• Constraints on the location of $\gamma$-ray emitting region for a sample of blazars with radio core-shift measurements
• Exploring the connection between radio and GeV-TeV gamma-ray emission in the 1FHL and 2FHL AGN samples
• Probing photon-ALP oscillations from the flat spectrum radio quasar 4C+21.35
• Similarity of Jet Radiation between Flat Spectrum Radio Quasars and GeV Narrow-Line Seyfert 1 Galaxies: A Universal $\delta$-$L_{\mathrm{c}}$ Correlation
• Modeling the spectral-energy-distribution of 3C 454.3 in a "flat" broad-line-region scenario
• Axion-like Particle Effects on Photon Polarization in High-Energy Astrophysics
• Pair Cascades at the Edge of the Broad-Line Region Shaping the Gamma-Ray Spectrum of 3C 279
• Locating the GeV Emission Region in the Jets of Blazars from Months-Timescale Multi-Wavelength Outbursts
• Propagation of very-high-energy $\gamma$-rays from distant blazars
• Revisiting Correlations Between Broad-Line and Jet Emission Variations for AGNs: 3C 120 and 3C 273
• First detection of VHE gamma-ray signal from the FSRQ TON 0599
• Prospects of additional contribution at Optical-NIR band of EBL in the light of VHE spectra
• VLTI-GRAVITY observations of blazars
• A long-term multiwavelength study of the flat spectrum radio quasar OP 313
• On the radio and GeV-TeV gamma-ray emission connection in Fermi blazars