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The Galactic Center excess (GCE) of GeV $\gamma$ rays may hint at dark matter (DM), yet its origin remains debated. Motivated by this, we survey weakly interacting massive particle (WIMP) models that can fit the GCE while satisfying…

High Energy Physics - Phenomenology · Physics 2026-04-07 Chuiyang Kong , Mattia Di Mauro

We explore models for the GeV Galactic Center Excess (GCE) observed by the Fermi Telescope, focusing on $\chi \chi \rightarrow f \bar f$ annihilation processes in the $Z_3$ NMSSM. We begin by examining the requirements for a simplified…

High Energy Physics - Phenomenology · Physics 2014-10-22 Clifford Cheung , Michele Papucci , David Sanford , Nausheen R. Shah , Kathryn M. Zurek

The Galactic diffuse X-ray emission (GDXE) can be spatially segmented into the Galactic center X-ray Emission (GCXE), the Galactic ridge X-ray emission (GRXE), and the Galactic bulge X-ray emission (GBXE). The X-ray spectra of the GDXE are…

High Energy Astrophysical Phenomena · Physics 2024-01-19 Katsuji Koyama , Masayoshi Nobukawa

The possible gamma-ray excess in the inner Galaxy and the Galactic center (GC) suggested by Fermi-LAT observations has triggered a large number of studies. It has been interpreted as a variety of different phenomena such as a signal from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Francesca Calore , Ilias Cholis , Christoph Weniger

We present an analysis of the compatibility between the Galactic Centre Excess (GCE) and the Constrained MSSM (CMSSM). We perform a global fit to the relevant experimental data including the GCE taking into account the systematic…

High Energy Physics - Phenomenology · Physics 2015-10-06 Andrew J. Williams

We study the spatial distribution of a 95% complete sample of 508 X-ray point sources (XPS) detected in the 0.5-2.0 keV band in Chandra ACIS-I observations of 51 massive galaxy clusters found in the MACS survey. Covering the redshift range…

Astrophysics · Physics 2009-11-10 Joshua T. Ruderman , Harald Ebeling

Recent observations of cosmic rays (CRs) have revealed a two-component anomaly in the spectra of primary and secondary particles, as well as their ratios, prompting investigation into their common origin. In this study, we incorporate the…

High Energy Astrophysical Phenomena · Physics 2024-03-08 Yu-Hua Yao , Xu-Lin Dong , Yi-Qing Guo , Qiang Yuan

The unexpectedly high flux of cosmic ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the HighAltitude…

High Energy Astrophysical Phenomena · Physics 2017-11-17 A. U. Abeysekara , A. Albert , R. Alfaro , C. Alvarez , J. D. Álvarez , R. Arceo , J. C. Arteaga-Velázquez , D. Avila Rojas , H. A. Ayala Solares , A. S. Barber , N. Bautista-Elivar , A. Becerril , E. Belmont-Moreno , S. Y. BenZvi , D. Berley , A. Bernal , J. Braun , C. Brisbois , K. S. Caballero-Mora , T. Capistrán , A. Carramiñana , S. Casanova , M. Castillo , U. Cotti , J. Cotzomi , S. Coutiño de León , C. De León , E. De la Fuente , B. L. Dingus , M. A. DuVernois , J. C. Díaz-Vélez , R. W. Ellsworth , K. Engel , O. Enríquez-Rivera , D. W. Fiorino , N. Fraija , J. A. García-González , F. Garfias , M. Gerhardt , A. González Muñoz , M. M. González , J. A. Goodman , Z. Hampel-Arias , J. P. Harding , S. Hernández , A. Hernández-Almada , J. Hinton , B. Hona , C. M. Hui , P. Hüntemeyer , A. Iriarte , A. Jardin-Blicq , V. Joshi , S. Kaufmann , D. Kieda , A. Lara , R. J. Lauer , W. H. Lee , D. Lennarz , H. León Vargas , J. T. Linnemann , A. L. Longinotti , G. Luis Raya , R. Luna-García , R. López-Coto , K. Malone , S. S. Marinelli , O. Martinez , I. Martinez-Castellanos , J. Martínez-Castro , H. Martínez-Huerta , J. A. Matthews , P. Miranda-Romagnoli , E. Moreno , M. Mostafá , L. Nellen , M. Newbold , M. U. Nisa , R. Noriega-Papaqui , R. Pelayo , J. Pretz , E. G. Pérez-Pérez , Z. Ren , C. D. Rho , C. Rivière , D. Rosa-González , M. Rosenberg , E. Ruiz-Velasco , H. Salazar , F. Salesa Greus , A. Sandoval , M. Schneider , H. Schoorlemmer , G. Sinnis , A. J. Smith , R. W. Springer , P. Surajbali , I. Taboada , O. Tibolla , K. Tollefson , I. Torres , T. N. Ukwatta , G. Vianello , T. Weisgarber , S. Westerhoff , I. G. Wisher , J. Wood , T. Yapici , G. Yodh , P. W. Younk , A. Zepeda , H. Zhou , F. Guo , J. Hahn , H. Li , H. Zhang

We have observed the Galactic Center (GC) region at 0.154 and 0.255 GHz with the GMRT. A total of 62 compact likely extragalactic sources are detected. Their scattering sizes go down linearly with increasing angular distance from the GC up…

Astrophysics of Galaxies · Physics 2015-06-16 Subhashis Roy

We revisit the idea that the Galactic center (GC) is the dominant source of Galactic cosmic rays (GCRs), based on a series of new observational evidence. A unified model is proposed to explain the new phenomena of GCRs and $\gamma$-rays…

High Energy Astrophysical Phenomena · Physics 2013-01-24 Yiqing Guo , Zhaoyang Feng , Qiang Yuan , Cheng Liu , Hongbo Hu

Several groups of authors have analyzed Fermi LAT data in a region around the Galactic Center finding an unaccounted gamma-ray excess over diffuse backgrounds in the GeV energy range. It has been argued that it is difficult or even…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Jovana Petrovic , Pasquale D. Serpico , Gabrijela Zaharijas

Multiple stellar populations in globular clusters (GCs) are distinct by their different abundances of light elements. The abundance anti-correlations point towards a nucleosynthesis origin due to high-temperature H burning, but it remains…

Astrophysics of Galaxies · Physics 2021-02-03 Eugenio Carretta , Angela Bragaglia

We report on an analysis of data from the southern hemisphere SUGAR cosmic ray detector. We confirm the existence of an excess of $10^{18}$eV cosmic rays from a direction close to the Galactic Centre, first reported by the AGASA group. We…

Astrophysics · Physics 2009-10-31 J. A. Bellido , R. W. Clay , B. R. Dawson , M. Johnston-Hollitt

In this paper we analyze the biasing effect of point sources, either thermal Sunyaev-Zeldovich clusters or standard radio sources, on the estimated strength of the non-Gaussianity in the Cosmic Microwave Background (CMB). We show that the…

Astrophysics · Physics 2008-11-26 Daniel Babich , Elena Pierpaoli

The flux of cosmic-ray high-energy positrons has recently been measured by AMS with unprecedented precision. This flux is well above the expectation from secondary positrons made by the observed fluxes of nuclear cosmic rays impinging on…

High Energy Physics - Phenomenology · Physics 2019-09-05 A. De Rújula

Evidence of excess GeV emission nearly coinciding with the Galactic Centre has been interpreted as a possible signature of annihilating dark matter. In this paper, we argue that it seems too early to discard pulsars as a viable explanation…

High Energy Astrophysical Phenomena · Physics 2015-06-17 N. Mirabal

The positron fraction in cosmic rays was found to be a steadily increasing in function of energy, above $\sim$ 10 GeV. This behaviour contradicts standard astrophysical mechanisms, in which positrons are secondary particles, produced in the…

High Energy Astrophysical Phenomena · Physics 2015-02-25 M. Boudaud , S. Aupetit , S. Caroff , A. Putze , G. Belanger , Y. Genolini , C. Goy , V. Poireau , V. Poulin , S. Rosier , P. Salati , L. Tao , M. Vecchi

The diffuse Fe XXV (6.7 keV) line emission observed in the Galactic ridge is widely accepted to be produced by a superposition of a large number of unresolved X-ray point sources. In the very central degrees of our Galaxy, however, the…

It has recently been demonstrated that the $\gamma$-ray emission spectrum of the EGRET-identified, central Galactic source 2EG J1746-2852 can be well fitted by positing that these photons are generated by the decay of $\pi^0$'s produced in…

Astrophysics · Physics 2009-10-31 R. M. Crocker , F. Melia , R. R. Volkas

The Galactic Center X-ray Emission (GCXE) is composed of high temperature (7 keV) and low temperature (1 keV) plasmas (HTP and LTP, respectively). The global structure of the HTP is roughly uniform over the Galactic center (GC) region, and…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Shigeo Yamauchi , Miku Shimizu , Masayoshi Nobukawa , Kumiko K. Nobukawa , Hideki Uchiyama , Katsuji Koyama
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