Estimation of the Extragalactic Background Light using TeV Observations of BL~Lacs

Abstract

The very high energy (VHE) gamma ray spectral index of high energy peaked blazars correlates strongly with its corresponding redshift whereas no such correlation is observed in the X-ray or the GeV bands. We attribute this correlation to a result of photon-photon absorption of TeV photons with the extragalactic background light (EBL) and utilizing this, we compute the allowed flux range for the EBL, which is independent of previous estimates. The observed VHE spectrum of the sources in our sample can be well approximated by a power-law, and if the de-absorbed spectrum is also assumed to be a power law, then we show that the spectral shape of EBL will be $\epsilon n(\epsilon )\sim klog(\frac{\epsilon }{{\epsilon }_p})$. We estimate the range of values for the parameters defining the EBL spectrum, $k$ and ${\epsilon }_p$, such that the correlation of the intrinsic VHE spectrum with redshift is nullified. The estimated EBL depends only on the observed correlation and the assumption of a power law source spectrum. Specifically, it does not depend on the spectral modeling or radiative mechanism of the sources, nor does it depend on any theoretical shape of the EBL spectrum obtained through cosmological calculations. The estimated EBL spectrum is consistent with the upper and lower limits imposed by different observations. Moreover, it also agrees closely with the theoretical estimates obtained through cosmological evolution models.

arXiv comment28 pages, 5 figures, Accepted for publication in The Astrophysical Journal

References in corpus (75)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• A Unifying View of the Spectral Energy Distributions of Blazars
• The extragalactic optical-infrared background radiations, their time evolution and the cosmic photon-photon opacity
• The Cosmic Infrared Background: Measurements and Implications
• Extragalactic Background Light Inferred from AEGIS Galaxy SED-type Fractions
• The COBE Diffuse Infrared Background Experiment Search for the Cosmic Infrared Background: I. Limits and Detections
• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• The 70 Month Swift-BAT All-Sky Hard X-Ray Survey
• Modeling the Extragalactic Background Light from Stars and Dust
• A low level of extragalactic background light as revealed by gamma-rays from blazars
• The COBE Diffuse Infrared Background Experiment Search for the Cosmic Infrared Background: II. Model of the Interplanetary Dust Cloud
• Constraints on the Physical Parameters of TeV Blazars
• Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?
• Deep Galaxy Counts, Extragalactic Background Light, and the Stellar Baryon Budget
• Intergalactic Photon Spectra from the Far IR to the UV Lyman Limit for $0<z<6$ and the Optical Depth of the Universe to High Energy Gamma-Rays
• The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
• New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200
• Hard X-ray properties of blazars
• New limits on the density of the extragalactic background light in the optical to the far-infrared from the spectra of all known TeV blazars
• TeV candidate BL Lac objects
• Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S
• A Lower-Limit Flux for the Extragalactic Background Light
• Simultaneous observations of PKS 2155-304 with H.E.S.S., Fermi, RXTE and ATOM: spectral energy distributions and variability in a low state
• GeV Gamma-Ray Attenuation and the High-Redshift UV Background
• Angular Power Spectra of the COBE DIRBE Maps
• Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe
• Six years of BeppoSAX observations of blazars: a spectral catalog
• Constraints on the Extragalactic Infrared Background from Gamma Ray Observations of Mrk 501
• Discovery of Very High Energy gamma-rays from 1ES 1011+496 at z=0.212
• Discovery of VHE gamma-rays from the distant BL Lac 1ES 0347-121
• Detection of the cosmic γ-ray horizon from multiwavelength observations of blazars
• Discovery of Very High Energy $\gamma$-Rays from Markarian~180 Triggered by an Optical Outburst
• Simultaneous multiwavelength observations of the blazar 1ES1959+650 at a low TeV flux
• Transparency of the Universe to gamma rays
• The Discovery of gamma-Ray Emission From The Blazar RGB J0710+591
• Photon propagation and the VHE gamma-ray spectra of blazars: how transparent is really the Universe?
• The Firm Redshift Lower Limit of the Most Distant TeV-Detected Blazar PKS 1424+240
• Mrk 421 active state in 2008: the MAGIC view, simultaneous multi-wavelength observations and SSC model constrained
• Strong New Constraints on the Extragalactic Background Light in the Near- to Mid-IR
• Observation of very high energy gamma-rays from the AGN 1ES 2344+514 in a low emission state with the MAGIC telescope
• Limits on the extragalactic background light in the Fermi era
• Rapid and multi-band variability of the TeV-bright active nucleus of the galaxy IC 310
• Discovery of VHE gamma-rays from the blazar 1ES 1215+303 with the MAGIC Telescopes and simultaneous multi-wavelength observations
• Discovery of Very High Energy Gamma-Ray Emission from the BL Lac Object H2356-309 with the H.E.S.S. Cherenkov Telescopes
• Constraining blazar distances with combined Fermi and TeV data: an empirical approach
• Simultaneous X-Ray and Gamma-Ray Observations of TeV Blazars: Testing Synchro-Compton Emission Models and Probing the Infrared Extragalactic Background
• Discovery of VHE gamma-rays from the high-frequency-peaked BL Lac object RGB J0152+017
• Observational Gamma-ray Cosmology
• Discovery of Very High-Energy Gamma-Ray Radiation from the BL Lac 1ES 0806+524
• Simultaneous Multiwavelength observation of Mkn 501 in a low state in 2006
• Reconstructing the γ-ray Photon Optical Depth of the Universe to z~4 from Multiwavelength Galaxy Survey Data
• The TeV spectrum of H1426+428
• Discovery of High-energy and Very High Energy Gamma-ray Emission from the Blazar RBS 0413
• Evidence for a cosmological effect in γ-ray spectra of BL Lacs
• Constraints on the Extragalactic Background Light from Very High Energy Gamma-Ray Observations of Blazars
• Multiwavelength Observations of the Previously Unidentified Blazar RX J0648.7+1516
• H.E.S.S and Fermi-LAT discovery of gamma rays from the blazar 1ES 1312-423
• On the hadronic cascade scenario for extreme BL Lacs
• Multiwavelength observations of the AGN 1ES 0414+009 with VERITAS, Fermi-LAT, Swift-XRT, and MDM
• Upper Limits on the Extragalactic Background Light from the Gamma-Ray Spectra of Blazars
• Discovery of VHE gamma-rays from the BL Lac object PKS 0548-322
• Discovery of VHE gamma-ray emission from the BL Lac object B3 2247+381 with the MAGIC telescopes
• Discovery of VHE γ-ray emission and multi-wavelength observations of the BL Lac object 1RXS J101015.9-311909
• Extreme Blazars Studied with Fermi-LAT and Suzaku: 1ES 0347-121 and Blazar Candidate HESS J1943+213
• Discovery of very high energy gamma-ray emission from the BL Lac object PKS 0301-243 with H.E.S.S
• A Simple Analytic Treatment of the Intergalactic Absorption Effect in Blazar Gamma-ray Spectra
• High-frequency-peaked BL Lacertae objects as spectral candles to measure the Extragalactic Background Light in the Fermi and air Cherenkov telescopes era
• Discovery of very high energy gamma-ray emission from the blazar 1ES 1727+502 with the MAGIC Telescopes
• Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state
• Discovery of high and very high-energy emission from the BL Lac object SHBL J001355.9-185406
• A Hard X-Ray View of Two Distant VHE Blazars: 1ES 1101-232 and 1ES 1553+113
• Derivation of a Relation for the Steepening of TeV Selected Blazar Gamma-ray Spectra with Energy and Redshift
• Intrinsic VHE Gamma-ray spectra of Blazars as a probe for Extragalactic Background Light
• Constraining Extragalactic Background Light From TeV Blazars
• The TeV Blazar Measurement of the Extragalactic Background Light

Cited by in corpus (11)

• The extragalactic background light, the Hubble constant, and anomalies: conclusions from 20 years of TeV gamma-ray observations
• Measurement of the EBL spectral energy distribution using the VHE gamma-ray spectra of H.E.S.S. blazars
• Cosmic absorption of ultra high energy particles
• Gamma-rays as probes of the Universe
• Normalization of the extragalactic background light from high-energy gamma-ray observations
• Model-independent Redshift Estimation of BL Lac Objects through VHE Observations
• Propagation of very-high-energy $\gamma$-rays from distant blazars
• Constraints on Extragalactic Background Light using TeV Observations of BL Lacertae objects
• Absorption of Photons from Distant Gamma-Ray Sources
• Detailed modelling of the EBL along VHE γ-ray paths
• Studies of Extragalactic Background Light with TeV BL Lac Objects