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

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-...

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Guardado en:
Detalles Bibliográficos
Publicado: 2013
Materias:
galaxies: active
galaxies: halos
gamma rays: galaxies
instrumentation: detectors
intergalactic medium
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v765_n1_p_Ackermann
http://hdl.handle.net/20.500.12110/paper_0004637X_v765_n1_p_Ackermann
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_0004637X_v765_n1_p_Ackermann
record_format dspace
spelling paper:paper_0004637X_v765_n1_p_Ackermann2023-06-08T14:29:10Z 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 galaxies: active galaxies: halos gamma rays: galaxies instrumentation: detectors intergalactic medium 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. © 2013. The American Astronomical Society. All rights reserved. 2013 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v765_n1_p_Ackermann http://hdl.handle.net/20.500.12110/paper_0004637X_v765_n1_p_Ackermann
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic galaxies: active
galaxies: halos
gamma rays: galaxies
instrumentation: detectors
intergalactic medium
spellingShingle galaxies: active
galaxies: halos
gamma rays: galaxies
instrumentation: detectors
intergalactic medium
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
topic_facet galaxies: active
galaxies: halos
gamma rays: galaxies
instrumentation: detectors
intergalactic medium
description 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. © 2013. The American Astronomical Society. All rights reserved.
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
title_short 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
title_full 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
title_fullStr 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
title_full_unstemmed 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
title_sort 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
publishDate 2013
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v765_n1_p_Ackermann
http://hdl.handle.net/20.500.12110/paper_0004637X_v765_n1_p_Ackermann
_version_ 1768541587732692992

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