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dc.contributor.author
The Fermi-lat Collaboration
dc.contributor.author
Ackermann, M.
dc.contributor.author
Cillis, Analia Nilda
dc.date.available
2015-06-11T16:29:15Z
dc.date.issued
2013-03
dc.identifier.citation
The Fermi-lat Collaboration; Ackermann, M.; Cillis, Analia Nilda; Determination of the Point-spread Function for the Fermi Large Area Telescope from On-orbit Data and Limits on Pair Halos of Active Galactic Nuclei; Iop Publishing Ltd; Astrophysical Journal; 765; 3-2013; 54-73
dc.identifier.issn
0004-637X
dc.identifier.uri
http://hdl.handle.net/11336/675
dc.description.abstract
The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to detect photons with energies from ≈20 MeV to >300 GeV. The pre-launch response functions of the LAT were determined through extensive Monte Carlo simulations and beam tests. The point-spread function (PSF) characterizing the angular distribution of reconstructed photons as a function of energy and geometry in the detector is determined here from two years of on-orbit data by examining the distributions of γ rays from pulsars and active galactic nuclei (AGNs). Above 3 GeV, the PSF is found to be broader than the pre-launch PSF. We checked for dependence of the PSF on the class of γ-ray source and observation epoch and found none. We also investigated several possible spatial models for pair-halo emission around BL Lac AGNs. We found no evidence for a component with spatial extension larger than the PSF and set upper limits on the amplitude of halo emission in stacked images of low- and high-redshift BL Lac AGNs and the TeV blazars 1ES0229+200 and 1ES0347?121.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
Iop Publishing Ltd
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
Galaxies: Active
dc.subject
Galaxies: Halos
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Gamma Rays: Galaxies,
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Instrumentation: Detectors, Intergalactic Medium
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Astronomía
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Ciencias Físicas
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CIENCIAS NATURALES Y EXACTAS
dc.title
Determination of the Point-spread Function for the Fermi Large Area Telescope from On-orbit Data and Limits on Pair Halos of Active Galactic Nuclei
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2016-03-30 10:35:44.97925-03
dc.journal.volume
765
dc.journal.pagination
54-73
dc.journal.pais
Reino Unido
dc.journal.ciudad
Londres
dc.description.fil
Fil: The Fermi-lat Collaboration. University Of Stanford. Physics Department;
dc.description.fil
Fil: Ackermann, M..
dc.description.fil
Fil: Cillis, Analia Nilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio(i); Argentina
dc.journal.title
Astrophysical Journal
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/arxiv/1309.5416
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://iopscience.iop.org/0004-637X/765/1/54/pdf/apj_765_1_54.pdf
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://arxiv.org/abs/1309.5416
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