English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Aims: We derive limits on the EBL density from the energy spectra of distantsources of very high energetic gamma-rays (VHE gamma-rays). Methods: VHEgamma-rays are attenuated by the photons of the EBL via pair production, whichleaves an imprint in the measured spectra from distant sources. In this paperwe present a new method to derive constraints on the EBL. Hereby, we use onlyvery basic assumptions about TeV blazar physics and no pre-defined EBL model,but rather a large number of generic shapes constructed from a grid in EBLdensity vs. wavelength. In our study we utilize spectral data from all knownTeV blazars, making this the most complete study so far. Results: We derivelimits on the EBL for three individual TeV blazar spectra (Mkn 501, H1426+428,1ES1101-232) and for all spectra combined. Combining the results fromindividual spectra leads to significantly stronger constraints over a widewavelength range from the optical (~ 1 micron) to the far-infrared (~ 80microns). The limits are only a factor of 2 to 3 above the absolute lowerlimits derived from source counts. In the mid-infrared our limits are thestrongest constraints derived from TeV blazar spectra so far. A high density ofthe EBL around 1 micron, reported by direct detection experiments, can beexcluded. Conclusions: Our results can be interpreted in two ways: (i) The EBLis almost resolved by source counts, leaving only little room for additionalcomponents by e.g. the first stars or (ii) the assumptions about the underlyingphysics are not valid, which would require substantial changes in the standardemission models of TeV blazars.Comment: 16 pages, 15 figures, A&A in pres

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