Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas

We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ∼ 6% of the Crab Nebula flux, the new VERITAS data reveal a prominent fla...

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Detalles Bibliográficos
Publicado: 2010
Materias:
Galaxies: active
Gamma rays:galaxies
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20418205_v709_n2PART2_pL163_Acciari
http://hdl.handle.net/20.500.12110/paper_20418205_v709_n2PART2_pL163_Acciari
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_20418205_v709_n2PART2_pL163_Acciari
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spelling paper:paper_20418205_v709_n2PART2_pL163_Acciari2023-06-08T16:33:13Z Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas Galaxies: active Gamma rays:galaxies We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ∼ 6% of the Crab Nebula flux, the new VERITAS data reveal a prominent flare reaching ∼ 20% of the Crab. While very high energy (VHE) flares are quite common in many nearby blazars, the case of 1ES 1218+304 (redshift z = 0.182) is particularly interesting since it belongs to a group of blazars that exhibit unusually hard VHE spectra considering their redshifts. When correcting the measured spectra for absorption by the extragalactic background light, 1ES 1218+304 and a number of other blazars are found to have differential photon indices Γ≤ 1.5. The difficulty in modeling these hard spectral energy distributions in blazar jets has led to a range of theoretical γ-ray emission scenarios, one of which is strongly constrained by these new VERITAS observations. We consider the implications of the observed light curve of 1ES 1218+304, which shows day scale flux variations, for shock acceleration scenarios in relativistic jets, and in particular for the viability of kiloparsec-scale jet emission scenarios. © 2010. The American Astronomical Society. All rights reserved. 2010 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20418205_v709_n2PART2_pL163_Acciari http://hdl.handle.net/20.500.12110/paper_20418205_v709_n2PART2_pL163_Acciari
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
Gamma rays:galaxies
spellingShingle Galaxies: active
Gamma rays:galaxies
Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas
topic_facet Galaxies: active
Gamma rays:galaxies
description We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ∼ 6% of the Crab Nebula flux, the new VERITAS data reveal a prominent flare reaching ∼ 20% of the Crab. While very high energy (VHE) flares are quite common in many nearby blazars, the case of 1ES 1218+304 (redshift z = 0.182) is particularly interesting since it belongs to a group of blazars that exhibit unusually hard VHE spectra considering their redshifts. When correcting the measured spectra for absorption by the extragalactic background light, 1ES 1218+304 and a number of other blazars are found to have differential photon indices Γ≤ 1.5. The difficulty in modeling these hard spectral energy distributions in blazar jets has led to a range of theoretical γ-ray emission scenarios, one of which is strongly constrained by these new VERITAS observations. We consider the implications of the observed light curve of 1ES 1218+304, which shows day scale flux variations, for shock acceleration scenarios in relativistic jets, and in particular for the viability of kiloparsec-scale jet emission scenarios. © 2010. The American Astronomical Society. All rights reserved.
title Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas
title_short Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas
title_full Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas
title_fullStr Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas
title_full_unstemmed Discovery of variability in the very high energy γ-ray emission of 1ES 1218+304 with veritas
title_sort discovery of variability in the very high energy γ-ray emission of 1es 1218+304 with veritas
publishDate 2010
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20418205_v709_n2PART2_pL163_Acciari
http://hdl.handle.net/20.500.12110/paper_20418205_v709_n2PART2_pL163_Acciari
_version_ 1768542524715040768

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