Searches for correlation between UHECR events and high-energy gamma-ray Fermi-LAT data
| dc.contributor.author | Álvarez, Ezequiel | |
| dc.contributor.author | Cuoco, Alessandro | |
| dc.contributor.author | Mirabal, Nestor | |
| dc.contributor.author | Zaharijas, Gabrijela | |
| dc.date.accessioned | 2020-08-31T18:19:46Z | |
| dc.date.available | 2020-08-31T18:19:46Z | |
| dc.date.issued | 2016-12-13 | |
| dc.description.abstract | The astrophysical sources responsible for ultra high-energy cosmic rays (UHECRs) continue to be one of the most intriguing mysteries in astrophysics. We present a comprehensive search for correlations between high-energy (gsim 1 GeV) gamma-ray events from the Fermi Large Area Telescope (LAT) and UHECRs (gsim 60 EeV) detected by the Telescope Array and the Pierre Auger Observatory. We perform two separate searches. First, we conduct a standard cross-correlation analysis between the arrival directions of 148 UHECRs and 360 gamma-ray sources in the Second Catalog of Hard Fermi-LAT sources (2FHL). Second, we search for a possible correlation between UHECR directions and unresolved Fermi-LAT gamma-ray emission. For the latter, we use three different methods: a stacking technique with both a model-dependent and model-independent background estimate, and a cross-correlation function analysis. We also test for statistically significant excesses in gamma rays from signal regions centered on Cen A and the Telescope Array hotspot. No significant correlation is found in any of the analyses performed, except a weak (lesssim 2σ) hint of signal with the correlation function method on scales ~ 1°. Upper limits on the flux of possible power-law gamma-ray sources of UHECRs are derived. | en_US |
| dc.description.sponsorship | The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat `a l’Energie Atomique and the Centre National de la Recherche Scientifique / Institut National de Physique Nucl´eaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture,Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Etudes ´Spatiales in France. Authors are grateful to Giacomo Bonnoli for comments on the work. E.A. acknowledges partial supported by ANPCyT PICT 2011-0359 and Asociaci´on Universitaria Iberoam´ericana de Postgrado. E.A. and G.Z. are grateful to ICTP for hospitality during development of part of the project. This research was supported by a senior appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by Universities Space Research Association through a contract with NASA. | en_US |
| dc.description.uri | https://iopscience.iop.org/article/10.1088/1475-7516/2016/12/023 | en_US |
| dc.format.extent | 24 pages | en_US |
| dc.genre | journal articles preprints | en_US |
| dc.identifier | doi:10.13016/m2u4rw-sb5r | |
| dc.identifier.citation | Ezequiel Álvarez et al., Searches for correlation between UHECR events and high-energy gamma-ray Fermi-LAT data, Journal of Cosmology and Astroparticle Physics, Volume 2016 (2016), doi: 10.1088/1475-7516/2016/12/023 | en_US |
| dc.identifier.uri | 10.1088/1475-7516/2016/12/023 | |
| dc.identifier.uri | http://hdl.handle.net/11603/19546 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | IOP | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Physics Department Collection | |
| dc.relation.ispartof | UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II) | |
| dc.relation.ispartof | UMBC Joint Center for Earth Systems Technology (JCET) | |
| dc.rights | This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author. | |
| dc.rights | This is the version of the article before peer review or editing, as submitted by an author to Journal of Cosmology and Astroparticle Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at 10.1088/1475-7516/2016/12/023. | |
| dc.title | Searches for correlation between UHECR events and high-energy gamma-ray Fermi-LAT data | en_US |
| dc.type | Text | en_US |