Roncadelli, M. ; Galanti, G. ; De Angelis, A. ; Bignami, G. F.

2015
Verlag Deutsches Elektronen-Synchrotron Hamburg
ISBN: 978-3-935702-43-0

2015Roncadelli, Marco "ALPs Explain the Observed Redshift-Dependence of Blazar Spectra" in Proceedings, 11th Patras Workshop on Axions, WIMPs and WISPs (Axion-WIMP 2015) / Irastorza, Igor G., Redondo, Javier, Carmona, José Manuel, Cebrian, Susana, Dafni, Theopisti, Iguaz, Francisco J., Luzon, Gloria (eds.), Verlag Deutsches Elektronen-Synchrotron : 2015 ; AXION-WIMP 2015 : 11th Patras Workshop on Axions, WIMPs and WISPs, 2015-06-22 - 2015-06-26, Zaragoza
11th Patras Workshop on Axions, WIMPs and WISPs, AXION-WIMP 2015, ZaragozaZaragoza, Spain, 22 Jun 2015 - 26 Jun 20152015-06-222015-06-26 Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-PROC 82-87 (2015) [10.3204/DESY-PROC-2015-02/roncadelli_marco]2015  

Abstract: We considered a complete sample of blazars observed with the Imaging Atmospheric Cherenkov Telescopes above $E \geq 80 \, {\rm GeV}$, out to $z = 0.54$ and described by standard photon emission models which predict simple power-law spectra to a good approximation. We first show that the best-fit regression line of the emitted slope distribution $\{\Gamma_{\rm em} (z) \}$ decreases with $z$, in disagreement with physical intuition. Next, we demonstrate that, by allowing for photon-ALP oscillations in intergalactic space, for a realistic values of the parameters the best-fit regression line becomes exactly horizontal in the $\Gamma_{\rm em} - z$ plane. This result is amazing, because it is the only possibility in agreement with physical expectation, and so it can be regarded as a strong hint of the existence of an ALP.

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Book/Proceedings/Report Irastorza, I. G. (Editor) ; Redondo, J. (Editor) ; Carmona, J. M. (Editor) ; Cebrian, S. (Editor) ; Dafni, T. (Editor) ; Iguaz, F. J. (Editor) ; Luzon, G. (Editor)
Proceedings, 11th Patras Workshop on Axions, WIMPs and WISPs (Axion-WIMP 2015)
201511th Patras Workshop on Axions, WIMPs and WISPs, AXION-WIMP 2015, ZaragozaZaragoza, Spain, 22 Jun 2015 - 26 Jun 20152015-06-222015-06-26 Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-PROC 1-251 (2015) [10.3204/DESY-PROC-2015-02]2015     Files BibTeX | EndNote: XML, Text | RIS