Hint at an axion-like particle from the redshift dependence of blazar spectra
We consider the largest observed sample including all intermediate-frequency peaked (IBL) and high-frequency peaked (HBL) flaring blazars above 100 GeV up to redshift $z = 0.6$. We show that the best-fit regression line of the emitted spectral indices $Γ_{\rm em} (z)$ is a concave parabola decreasin...
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ftdatacite:10.48550/arxiv.1503.04436 2023-05-15T18:30:59+02:00 Hint at an axion-like particle from the redshift dependence of blazar spectra Galanti, Giorgio Roncadelli, Marco De Angelis, Alessandro Bignami, Giovanni F. 2015 https://dx.doi.org/10.48550/arxiv.1503.04436 https://arxiv.org/abs/1503.04436 unknown arXiv https://dx.doi.org/10.1093/mnras/stz3410 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ High Energy Astrophysical Phenomena astro-ph.HE High Energy Physics - Phenomenology hep-ph FOS Physical sciences article-journal Article ScholarlyArticle Text 2015 ftdatacite https://doi.org/10.48550/arxiv.1503.04436 https://doi.org/10.1093/mnras/stz3410 2022-04-01T12:29:51Z We consider the largest observed sample including all intermediate-frequency peaked (IBL) and high-frequency peaked (HBL) flaring blazars above 100 GeV up to redshift $z = 0.6$. We show that the best-fit regression line of the emitted spectral indices $Γ_{\rm em} (z)$ is a concave parabola decreasing as $z$ increases, thereby implying a statistical correlation between the $\{Γ_{\rm em} (z) \}$ distribution and $z$. This result contradicts our expectation that such a distribution should be $z$-independent. We argue that the above correlation does not arise from any selection bias. We show that our expectation naturally emerges provided that axion-like particles (ALPs) are put into the game. Moreover, ALPs can also explain why flat spectrum radio quasars emit up to 400 GeV, in sharp contradiction with conventional physics. So, the combination of the two very different but consistent results -- taken at face value -- leads to a hint at an ALP with mass $m = {\cal O} (10^{-10} \, {\rm eV})$ and two-photon coupling in the range $2.94 \times 10^{- 12} \, {\rm GeV}^{- 1} < g_{a γγ} < 0.66 \times 10^{- 10} \, {\rm GeV}^{- 1}$. As a bonus, the Universe would become considerably more transparent above energies $E \gtrsim 1 \, {\rm TeV}$ than dictated by conventional physics. Our prediction can be checked not only by the new generation of observatories like CTA, HAWC, GAMMA-400, LHAASO, TAIGA-HiSCORE and HERD, but also thanks to the planned laboratory experiments ALPS II (upgraded), STAX, IAXO and with other techniques now being developed by Avignone and collaborators. : 13 pages, 14 figures. This version matches the published paper: MNRAS 493, 1553 (2020) Text taiga DataCite Metadata Store (German National Library of Science and Technology) |
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High Energy Astrophysical Phenomena astro-ph.HE High Energy Physics - Phenomenology hep-ph FOS Physical sciences |
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High Energy Astrophysical Phenomena astro-ph.HE High Energy Physics - Phenomenology hep-ph FOS Physical sciences Galanti, Giorgio Roncadelli, Marco De Angelis, Alessandro Bignami, Giovanni F. Hint at an axion-like particle from the redshift dependence of blazar spectra |
topic_facet |
High Energy Astrophysical Phenomena astro-ph.HE High Energy Physics - Phenomenology hep-ph FOS Physical sciences |
description |
We consider the largest observed sample including all intermediate-frequency peaked (IBL) and high-frequency peaked (HBL) flaring blazars above 100 GeV up to redshift $z = 0.6$. We show that the best-fit regression line of the emitted spectral indices $Γ_{\rm em} (z)$ is a concave parabola decreasing as $z$ increases, thereby implying a statistical correlation between the $\{Γ_{\rm em} (z) \}$ distribution and $z$. This result contradicts our expectation that such a distribution should be $z$-independent. We argue that the above correlation does not arise from any selection bias. We show that our expectation naturally emerges provided that axion-like particles (ALPs) are put into the game. Moreover, ALPs can also explain why flat spectrum radio quasars emit up to 400 GeV, in sharp contradiction with conventional physics. So, the combination of the two very different but consistent results -- taken at face value -- leads to a hint at an ALP with mass $m = {\cal O} (10^{-10} \, {\rm eV})$ and two-photon coupling in the range $2.94 \times 10^{- 12} \, {\rm GeV}^{- 1} < g_{a γγ} < 0.66 \times 10^{- 10} \, {\rm GeV}^{- 1}$. As a bonus, the Universe would become considerably more transparent above energies $E \gtrsim 1 \, {\rm TeV}$ than dictated by conventional physics. Our prediction can be checked not only by the new generation of observatories like CTA, HAWC, GAMMA-400, LHAASO, TAIGA-HiSCORE and HERD, but also thanks to the planned laboratory experiments ALPS II (upgraded), STAX, IAXO and with other techniques now being developed by Avignone and collaborators. : 13 pages, 14 figures. This version matches the published paper: MNRAS 493, 1553 (2020) |
format |
Text |
author |
Galanti, Giorgio Roncadelli, Marco De Angelis, Alessandro Bignami, Giovanni F. |
author_facet |
Galanti, Giorgio Roncadelli, Marco De Angelis, Alessandro Bignami, Giovanni F. |
author_sort |
Galanti, Giorgio |
title |
Hint at an axion-like particle from the redshift dependence of blazar spectra |
title_short |
Hint at an axion-like particle from the redshift dependence of blazar spectra |
title_full |
Hint at an axion-like particle from the redshift dependence of blazar spectra |
title_fullStr |
Hint at an axion-like particle from the redshift dependence of blazar spectra |
title_full_unstemmed |
Hint at an axion-like particle from the redshift dependence of blazar spectra |
title_sort |
hint at an axion-like particle from the redshift dependence of blazar spectra |
publisher |
arXiv |
publishDate |
2015 |
url |
https://dx.doi.org/10.48550/arxiv.1503.04436 https://arxiv.org/abs/1503.04436 |
genre |
taiga |
genre_facet |
taiga |
op_relation |
https://dx.doi.org/10.1093/mnras/stz3410 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1503.04436 https://doi.org/10.1093/mnras/stz3410 |
_version_ |
1766214608800972800 |