The Blazar Emission Environment: Insight from Soft X-ray Absorption

Abstract

Collecting experimental insight into the relativistic particle populations and emission mechanisms at work within TeV-emitting blazar jets, which are spatially unresolvable in most bands and have strong beaming factors, is a daunting task. New observational information has the potential to lead to major strides in understanding the acceleration site parameters. Detection of molecular carbon monoxide (CO) in TeV emitting blazars, however, implies the existence of intrinsic gas, a connection often found in photo-dissociated region models and numerical simulations. The existence of intrinsic gas within a blazar could provide a target photon field for Compton up-scattering of photons to TeV energies by relativistic particles. We investigate the possible existence of intrinsic gas within the three TeV emitting blazars RGB J0710+591, W Comae and 1ES 1959+650 which have measurements or upper limits on molecular CO line luminosity using an independent technique which is based on the spectral analysis of soft X-rays. Evidence for X-ray absorption by additional gas beyond that measured within the Milky Way is searched for in Swift X-ray Telescope (XRT) data between 0.3 and 10 keV. Without complementary information from another measurement, additional absorption could be misinterpreted as an intrinsically curved X-ray spectrum since both models can frequently fit the soft X-ray data. After breaking this degeneracy, we do not find evidence for intrinsically curved spectra for any of the three blazars. Moreover, no evidence for intrinsic gas is evident for RGB J0710+591 and W Comae, while the 1ES 1959+650 XRT data support the existence of intrinsic gas with a column density of $\sim 1\times 10^{21}$cm${}^{-2}$.

ApJ accepted 29 April 2013

References in corpus (4)

• The Atomic to Molecular Transition in Galaxies. II: HI and H_2 Column Densities
• The blazar sequence: a new perspective
• X-ray spectral evolution of TeV BL Lac objects: eleven years of observations with BeppoSAX, XMM-Newton and SWIFT satellites
• A search of CO emission lines in blazars: the low molecular gas content of BL Lac objects compared to quasars

Cited by in corpus (10)

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• X-ray Absorption of High Redshift Quasars
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• Probing the physical properties of the intergalactic medium using blazars
• Long-term hard X-ray variability properties of Swift-BAT blazars
• Constraining X-ray emission in HBL blazars using multiwavelength observations
• X-Ray Spectral Variability of Thirteen TeV High Energy Peaked Blazars with XMM-Newton
• Probing the physical properties of the IGM using SRG/eROSITA spectra from blazars
• Investigating the variability of Swift-BAT blazars with NICER