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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
- Source :
- The Astrophysical Journal, The Astrophysical Journal, American Astronomical Society, 2013, 765, pp.54. ⟨10.1088/0004-637X/765/1/54⟩, The Astrophysical Journal, 2013, 765, pp.54. ⟨10.1088/0004-637X/765/1/54⟩, The astrophysical journal 765(1), 54 (2013). doi:10.1088/0004-637X/765/1/54
- Publication Year :
- 2013
- Publisher :
- HAL CCSD, 2013.
-
Abstract
- The astrophysical journal 765(1), 54 (2013). doi:10.1088/0004-637X/765/1/54<br />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<br />Published by Univ.11032, Chicago, Ill. [u.a.]
- Subjects :
- Ciencias Físicas
EXTRAGALACTIC MAGNETIC-FIELDS
halo [galaxies]
galaxies: halos
Astrophysics
01 natural sciences
galaxies, [gamma rays]
law.invention
Spitzer Space Telescope
law
1ES 0229+200
SPACE-TELESCOPE
010303 astronomy & astrophysics
Physics
TEV BLAZARS
detector [instrumentation]
[SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
Astrophysics::Instrumentation and Methods for Astrophysics
detectors, intergalactic medium [instrumentation]
VHE GAMMA-RAYS
galaxies: active – galaxies: halos – gamma rays: galaxies – instrumentation: detectors – intergalactic medium
halos [galaxies]
active [galaxies]
intergalactic medium
Astrophysics - High Energy Astrophysical Phenomena
CIENCIAS NATURALES Y EXACTAS
Point spread function
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
Active galactic nucleus
Astrophysics::High Energy Astrophysical Phenomena
galaxies: active
Astrophysics::Cosmology and Extragalactic Astrophysics
Telescope
0103 physical sciences
gamma rays: galaxies
instrumentation: detectors
galaxie [gamma rays]
Blazar
SOURCE CATALOG
Astrophysics::Galaxy Astrophysics
BACKGROUND LIGHT
010308 nuclear & particles physics
Astronomy
CONSTRAINTS
Astronomy and Astrophysics
Quasar
PULSAR
Galaxy
DISCOVERY
Astronomía
Space and Planetary Science
ddc:520
Fermi Gamma-ray Space Telescope
Subjects
Details
- Language :
- English
- ISSN :
- 0004637X and 15384357
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal, The Astrophysical Journal, American Astronomical Society, 2013, 765, pp.54. ⟨10.1088/0004-637X/765/1/54⟩, The Astrophysical Journal, 2013, 765, pp.54. ⟨10.1088/0004-637X/765/1/54⟩, The astrophysical journal 765(1), 54 (2013). doi:10.1088/0004-637X/765/1/54
- Accession number :
- edsair.doi.dedup.....1e7545ec7c56205d01aea445e2b2e9d5