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Related papers: Upper limit on the axion-photon coupling from Mark…

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The Hight Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory monitors the gamma-ray sky in the energy range from 100 GeV to 100 TeV and has detected two very high energy (VHE) blazars: Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501)…

High Energy Astrophysical Phenomena · Physics 2019-08-13 S. Coutiño de León , A. Carramiñana , D. Rosa-González

Highly variable Markarian 421 is a bright high synchrotron energy peaked blazar showing wide featureless non-thermal spectrum making it a good candidate for our study of intraday flux and spectral variations over time. We analyse its X-ray…

High Energy Astrophysical Phenomena · Physics 2024-11-07 A Priyana Noel , Haritma Gaur , Alok C. Gupta , Alicja Wierzcholska , Michal Ostrowski , Vinit Dhiman , Gopal Bhatta

The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high energy sky in the 300 GeV to $>100$ TeV energy range. HAWC has detected two blazars above $11\sigma$, Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501).…

We analyze 9 years of PASS 8 $\textit{Fermi}$-LAT data in the 60$-$500 MeV range and determine flux upper limits (UL) for 17 gamma-ray dark pulsars as a probe of axions produced by nucleon-nucleon Bremsstrahlung in the pulsar core. Using a…

High Energy Astrophysical Phenomena · Physics 2019-09-13 Sheridan J. Lloyd , Paula M. Chadwick , Anthony M. Brown

Axion-like particles (ALPs), predicted in theories beyond the Standard Model, can have observational effects on the transparency of the Universe to $\gamma$ rays in the presence of magnetic fields. In this work, we search for effects…

High Energy Astrophysical Phenomena · Physics 2020-10-30 Rolf Buehler , Galo Gallardo , Gernot Maier , Alberto Domínguez , Marcos López , Manuel Meyer

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…

High Energy Astrophysical Phenomena · Physics 2020-04-22 Giorgio Galanti , Marco Roncadelli , Alessandro De Angelis , Giovanni F. Bignami

Axion-like particles (ALPs) and photons can quantum mechanically interconvert when propagating through magnetic fields, and ALP-photon conversion may induce oscillatory features in the spectra of astrophysical sources. We use deep (370 ks),…

High Energy Physics - Phenomenology · Physics 2017-12-27 M. C. David Marsh , Helen R. Russell , Andrew C. Fabian , Brian R. McNamara , Paul Nulsen , Christopher S. Reynolds

Very high energy (VHE: >100 GeV) gamma rays coming from AGN can pair-produce on the intergalactic background light generating an electromagnetic cascade. If the Intergalactic Magnetic Field (IGMF) is sufficiently strong, this cascade may…

High Energy Astrophysical Phenomena · Physics 2014-06-19 Mateo Fernandez Alonso

High-energy photons may oscillate with axion-like particles (ALPs) when they propagate through the Milky Way's magnetic field, resulting in an alteration in the observed photon energy spectrum. The ultra-high energy gamma-ray spectra,…

High Energy Astrophysical Phenomena · Physics 2024-01-04 Jun Li , Xiao-Jun Bi , Lin-Qing Gao , Xiaoyuan Huang , Run-Min Yao , Peng-Fei Yin

We have searched for axions which could be produced in the solar core by exploiting their conversion to X rays in a strong laboratory magnetic field. The signature of the solar axion is an increase in the rate of the X rays detected in a…

High Energy Physics - Experiment · Physics 2008-11-26 Shigetaka Moriyama , Makoto Minowa , Toshio Namba , Yoshizumi Inoue , Yuko Takasu , Akira Yamamoto

Axion-like particles (ALPs) can couple to photons in strong magnetic fields, producing characteristic fluctuations in X-ray spectra. Using data from NASA's Neutron Star Interior Composition Explorer (NICER), we analyzed three pulsars: PSR…

High Energy Astrophysical Phenomena · Physics 2026-02-10 Yen-Jhen Liu , Yi Yang

We report a mm-wave search for axion dark matter from SGR 1745-2900, based on 4.8 h of ALMA observations. No candidate features are found between 133.99-135.78, 135.91-137.70, 145.99-147.78, and 147.99-149.78~GHz, corresponding to 0.55-0.62…

High Energy Physics - Phenomenology · Physics 2026-05-26 Javier De Miguel , Evanthia Hatziminaoglou , Frédéric Poidevin , Nanda Rea , Daniel L. Walker , Davide De Grandis , Jaime Prieto-Polo

The mixing of photons with axion-like particles (ALPs) in the large-scale magnetic field $B$ changes the polarization angle of a linearly polarized photon beam from active galactic nuclei in radio galaxies as it propagates over cosmological…

High Energy Astrophysical Phenomena · Physics 2012-06-13 D. Horns , L. Maccione , A. Mirizzi , M. Roncadelli

A search for solar axions has been performed using an axion helioscope which is equipped with a 2.3m-long 4T superconducting magnet, a gas container to hold dispersion-matching gas, PIN-photodiode X-ray detectors, and a telescope mount…

Astrophysics · Physics 2011-06-07 Y. Inoue , Y. Akimoto , R. Ohta , T. Mizumoto , A. Yamamoto , M. Minowa

We present multiwavelength observations of the BL Lacertae object Markarian 501 (Mrk 501) in 1997 between April 8 and April 19. Evidence of correlated variability is seen in very high energy (VHE, E > 350 GeV) gamma-ray observations taken…

Axions are a promising dark matter candidate that were motivated to solve the strong CP problem and that may also address the cosmological matter-antimatter asymmetry. Axion-photon conversion is possible in the presence of the strong…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-26 Jeremy Darling

An axion dark matter search with the CAPP-8TB haloscope is reported. Our results are sensitive to axion-photon coupling $g_{a\gamma\gamma}$ down to the QCD axion band over the axion mass range between 6.62 and 6.82 $\mu$eV at a 90\%…

High Energy Physics - Experiment · Physics 2020-03-18 S. Lee , S. Ahn , J. Choi , B. R. Ko , Y. K. Semertzidis

Axion-like particles (ALPs) are a broad class of pseudo-scalar bosons that generically arise from broken symmetries in extensions of the standard model. In many scenarios, ALPs can mix with photons in regions with high magnetic fields.…

High Energy Physics - Phenomenology · Physics 2022-03-10 Sunniva Jacobsen , Tim Linden , Katherine Freese

We report a pilot dark-matter search with a cryogenic, magnetized, scaled-down DALI prototype. An analysis of 36 hours of data reveals no statistically significant excess attributable to axionlike particles. We therefore set new exclusion…