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Related papers: Excess Radiation from Axion-Photon Conversion

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Axion-like particles (ALPs) can be produced by thermal processes in a stellar interior, escape from the star and, if sufficiently light, be converted into photons in the external Galactic magnetic field. Such a process could produce a…

High Energy Astrophysical Phenomena · Physics 2022-12-27 Mengjiao Xiao , Pierluca Carenza , Maurizio Giannotti , Alessandro Mirizzi , Kerstin M. Perez , Oscar Straniero , Brian W. Grefenstette

The 21-cm absorption feature reported by the EDGES collaboration is several times stronger than that predicted by traditional astrophysical models. If genuine, a deeper absorption may lead to stronger fluctuations on the 21-cm signal on…

Photoabsorption of atomic oxygen in the energy region below the $\rm 1s^{-1}$ threshold in x-ray spectroscopy from {\it Chandra} and {\it XMM-Newton} is observed in a variety of x-ray binary spectra. Photoabsorption cross sections…

High Energy Astrophysical Phenomena · Physics 2015-06-16 B. M. McLaughlin , C. P. Ballance , K. P. Bowen , D. J. Gardenghi , W. C. Stolte

Axion-like particles (ALPs) can account for the observed dark matter (DM) of the Universe and if their masses are at the eV scale, they can decay into infrared, optical and ultraviolet photons with a decay lifetime larger than the age of…

High Energy Physics - Phenomenology · Physics 2025-06-03 Arpan Kar , Sourov Roy , Pratick Sarkar

We perform a linear mode analysis of a uniformly distributed cloud of axion-like particles (ALPs) embedded in a magnetized intergalactic medium, in order to investigate the stability of axion stars under realistic astrophysical conditions.…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Kuldeep J. Purohit , Jitesh R. Bhatt , Subhendra Mohanty , Prashant K. Mehta

Axion-like particles (ALPs) are hypothetical entities often invoked to solve various problems in particle physics to cosmology. They are one of the most promising candidates to explain the elusive dark matter. A way to search for ALPs is…

High Energy Physics - Phenomenology · Physics 2023-08-29 Rafael Alves Batista , Cristina Viviente , Gaetano Di Marco , Miguel A. Sánchez-Conde

We derive updated cosmological bounds on light axion-like particles (ALPs) coupled to leptons or photons, using a full phase-space treatment of their production from the primordial thermal plasma. The ALP phase-space distribution, obtained…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-12 Nicola Barbieri , Luca Caloni , Martina Gerbino , Massimiliano Lattanzi , Luca Visinelli

Axion-like particles (ALPs) can induce localised oscillatory modulations in the spectra of photon sources passing through astrophysical magnetic fields. Ultra-deep Chandra observations of the Perseus cluster contain over $5 \times 10^5$…

High Energy Astrophysical Phenomena · Physics 2017-10-04 Marcus Berg , Joseph P. Conlon , Francesca Day , Nicholas Jennings , Sven Krippendorf , Andrew J. Powell , Markus Rummel

Axion-like particles (ALPs) are hypothetical pseudoscalar bosons that arise in many extensions of the Standard Model and are well-motivated dark matter candidates. Nearby massive stars in the late stages of stellar evolution provide a…

Axion-like particles (ALPs) are predicted by many extensions of the Standard Model (SM). When ALP mass lies in the range of MeV to GeV, the cosmology and astrophysics will be largely irrelevant. In this work, we investigate such light ALPs…

High Energy Physics - Phenomenology · Physics 2021-12-01 Daohan Wang , Lei Wu , Jin Min Yang , Mengchao Zhang

Axions and axion-like particles (ALPs) appear in many extensions of the Standard Model and are being investigated as promising dark matter (DM) candidates. One viable methodology for their detection involves the investigation of the…

High Energy Astrophysical Phenomena · Physics 2024-04-18 Wen-Qing Guo , Zi-Qing Xia , Xiaoyuan Huang

Photons may convert to axion-like particles (ALPs) in external magnetic fields. Under certain conditions, this effect should result in irregular features in observed spectra of astrophysical sources. Lack of such irregularities in…

High Energy Astrophysical Phenomena · Physics 2020-01-30 Maxim Libanov , Sergey Troitsky

High energy photons traveling through astrophysical magnetic fields have the potential to undergo oscillations with axion-like particles (ALPs), resulting in modifications to the observed photon spectrum. High energy $\gamma-$ray sources…

High Energy Astrophysical Phenomena · Physics 2025-02-20 Jun Li , Xiao-Jun Bi , Lin-Qing Gao , Peng-Fei Yin

We constrain the coupling between axionlike particles (ALPs) and photons, measured with the superconducting resonant detection circuit of a cryogenic Penning trap. By searching the noise spectrum of our fixed-frequency resonant circuit for…

The physical origin of radio emission in Radio Quiet Active Galactic Nuclei (RQ AGN) remains unclear, whether it is a downscaled version of the relativistic jets typical of Radio Loud (RL) AGN, or whether it originates from the accretion…

Astrophysics of Galaxies · Physics 2015-08-06 Ehud Behar , Ranieri D. Baldi , Ari Laor , Assaf Horesh , Jamie Stevens , Tasso Tzioumis

We examine the maximum possible strength of the global 21-cm absorption dip on the Cosmic Background Radiation at high-redshift caused by the atomic intergalactic medium, when the Lyman-$\alpha$ coupling is maximum, assuming no exotic…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-01 Pablo Villanueva-Domingo , Olga Mena , Jordi Miralda-Escudé

The high-energy Universe is potentially a great laboratory for searching new light bosons such as axion-like particles (ALPs). Cosmic sources are indeed the scene of violent phenomena that involve strong magnetic field and/or very long…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Pierre Brun

A prominent aspect of the hunt for cold dark matter is looking for light scalar candidates such as axion-like particles (ALPs). The coupling between ALPs and photons allows for the spontaneous decay of ALPs into pairs of photons. It has…

High Energy Astrophysical Phenomena · Physics 2022-03-08 Ahmed Ayad , Geoff Beck

Axions or more generally axion-like particles (ALPs) are pseudo-scalar particles predicted by many extensions of the Standard Model of particle physics (SM) and considered as highly viable candidates for dark matter (DM) in the universe. If…

High Energy Astrophysical Phenomena · Physics 2019-11-25 Ahmed Ayad , Geoff Beck

Bounds are derived on the axion-like particle (ALP) to two-photon coupling in the mass range $2.65-5.27$ eV. The bounds are obtained by searching for the signal from ALP decay in the Multi Unit Spectroscopic Explorer (MUSE) observations of…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-04 Elisa Todarello