An emerging population of BL Lacs with extreme properties: towards a class of EBL and cosmic magnetic field probes?

Abstract

High energy observations of extreme BL Lac objects, such as 1ES 0229+200 or 1ES 0347-121, recently focused interest both for blazar and jet physics and for the implication on the extragalactic background light and intergalactic magnetic field estimate. However, the number of these extreme highly peaked BL Lac objects (EHBL) is still rather small. Aiming at increase their number, we selected a group of EHBL candidates starting from the BL Lac sample of Plotkin et al. (2011), considering those undetected (or only barely detected) by the Large Area Telescope onboard Fermi and characterized by a high X-ray vs. radio flux ratio. We assembled the multi-wavelength spectral energy distribution of the resulting 9 sources, profiting of publicly available archival observations performed by the Swift, Galex and Fermi satellites, confirming their nature. Through a simple one-zone synchrotron self-Compton model we estimate the expected VHE flux, finding that in the majority of cases it is within the reach of present generation of Cherenkov arrays or of the forthcoming Cherenkov Telescope Array (CTA).

12 pages, 5 figures, accepted for publication in MNRAS

References in corpus (11)

• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• A hadronic origin for ultra-high-frequency-peaked BL Lac objects
• New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200
• Formation of hard VHE gamma-ray spectra of blazars due to internal photon-photon absorption
• The Hard VHE Gamma-ray Emission in High-Redshift TeV Blazars: Comptonization of Cosmic Microwave Background Radiation in an Extended Jet?
• Gamma-Ray and Neutrino Backgrounds as Probes of the High-Energy Universe: Hints of Cascades, General Constraints, and Implications for TeV Searches
• Sensitivity of the Cherenkov Telescope Array to the detection of axion-like particles at high gamma-ray opacities
• Blazar halos as probe for extragalactic magnetic fields and maximal acceleration energy
• Evidence for the Secondary Emission as the Origin of Hard Spectra in TeV Blazars
• Extreme Blazars Studied with Fermi-LAT and Suzaku: 1ES 0347-121 and Blazar Candidate HESS J1943+213
• Synchrotron pair halo and echo emission from blazars in the cosmic web: application to extreme TeV blazars

Cited by in corpus (21)

• 2WHSP: A catalog of HE and VHE gamma-ray blazars and blazar candidates
• The Gamma-Ray Window to Intergalactic Magnetism
• Leptonic and Hadronic Radiative Processes in Supermassive-Black-Hole Jets
• Search for Magnetically Broadened Cascade Emission From Blazars with VERITAS
• A new hard X-ray selected sample of extreme high-energy peaked BL Lac objects and their TeV gamma-ray properties
• ASTRI Mini-Array Core Science at the Observatorio del Teide
• Axion-like Particles Implications for High-Energy Astrophysics
• The Southern Wide-Field Gamma-Ray Observatory (SWGO): A Next-Generation Ground-Based Survey Instrument for VHE Gamma-Ray Astronomy
• TeV-peaked candidate BL Lac objects
• An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in an enhanced state
• Hunting extreme BL Lacertae blazars with Fermi-LAT
• The strange case of the transient HBL blazar 4FGL J1544.3-0649
• Broadband Study of High-Synchrotron-Peaked BL Lac Object 1ES 1218+304
• Relevance of VHE Blazar Spectra Models with Axion-Like Particles
• First detection of VHE gamma-ray emission from TXS~1515--273, study of its X-ray variability and spectral energy distribution
• Exploring the Most Extreme Gamma-Ray Blazars Using Broadband Spectral Energy Distributions
• A new look at the extragalactic Very High Energy sky: searching for TeV-emitting candidates among the X-ray bright, non-Fermi detected blazar population
• Disentangling the nature of the prototype radio weak BL Lac: Contemporaneous multifrequency observations of WISE J141046.00 + 740511.2
• Properties and Possible Physical Origins of $\gamma$-ray Emission in Extreme Synchrotron Blazars
• Constraining the synchrotron peak and estimating the VHE brightness of a sample of extreme high synchrotron peak blazars
• Extreme Blazars Observed with MAGIC: Second Catalog Release