Multiwavelength observations of Mrk 501 in 2008

Context. Blazars are variable sources on various timescales over a broad energy range spanning from radio to very high energy (>100 GeV, hereafter VHE). Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its first VHE detection in 1996. However, most of...

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Autores: MAGIC Collaboration, Munar i Adrover, Pere, Paredes i Poy, Josep Maria, Paredes Fortuny, Xavier, Ribó Gomis, Marc, Zanin, Roberta
Tipo de documento: artigo
Estado:Versión aceptada para publicación
Data de publicação:2014
País:España
Recursos:Universidad de Barcelona
Repositório:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/69565
Acesso em linha:https://hdl.handle.net/2445/69565
Access Level:Acceso aberto
Palavra-chave:Raigs gamma
Galàxies actives
Galàxies
Gamma rays
Active galaxies
Galaxies
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spelling Multiwavelength observations of Mrk 501 in 2008MAGIC CollaborationMunar i Adrover, PereParedes i Poy, Josep MariaParedes Fortuny, XavierRibó Gomis, MarcZanin, RobertaRaigs gammaGalàxies activesGalàxiesGamma raysActive galaxiesGalaxiesContext. Blazars are variable sources on various timescales over a broad energy range spanning from radio to very high energy (>100 GeV, hereafter VHE). Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its first VHE detection in 1996. However, most of the γ-ray studies performed on Mrk 501 during the past years relate to flaring activity, when the source detection and characterization with the available γ-ray instrumentation was easier toperform. Aims: Our goal is to characterize the source γ-ray emission in detail, together with the radio-to-X-ray emission, during the non-flaring (low) activity, which is less often studied than the occasional flaring (high) activity. Methods: We organized a multiwavelength (MW) campaign on Mrk 501 between March and May 2008. This multi-instrument effort included the most sensitive VHE γ-ray instruments in the northern hemisphere, namely the imaging atmospheric Cherenkov telescopes MAGIC and VERITAS, as well as Swift, RXTE, the F-GAMMA, GASP-WEBT, and other collaborations and instruments. This provided extensive energy and temporal coverage of Mrk 501 throughout the entire campaign. Results: Mrk 501 was found to be in a low state of activity during the campaign, with a VHE flux in the range of 10%-20% of the Crab nebula flux. Nevertheless, significant flux variations were detected with various instruments, with a trend of increasing variability with energy and a tentative correlation between the X-ray and VHE fluxes. The broadband spectral energy distribution during the two different emission states of the campaign can be adequately described within the homogeneous one-zone synchrotron self-Compton model, with the (slightly) higher state described by an increase in the electron number density. Conclusions: The one-zone SSC model can adequately describe the broadband spectral energy distribution of the source during the two months covered by the MW campaign. This agrees with previous studies of the broadband emission of this source during flaring and non-flaring states. We report for the first time a tentative X-ray-to-VHE correlation during such a low VHE activity. Although marginally significant, this positive correlation between X-ray and VHE, which has been reported many times during flaring activity, suggests that the mechanisms that dominate the X-ray/VHE emission during non-flaring-activity are not substantially different from those that are responsible for the emission during flaring activity. The data for Figs. 2 and 5 are only available at the CDS via anonymous ftp toSpringer Verlag2014info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersionapplication/pdfhttps://hdl.handle.net/2445/69565Articles publicats en revistes (Física Quàntica i Astrofísica)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésVersió postprint del document publicat a: http://dx.doi.org/10.1051/0004-6361/201322906Astronomy and Astrophysics, 2014, vol. 573, num. A50, p. 1-12http://dx.doi.org/10.1051/0004-6361/201322906(c) Springer Verlag, 2014info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/695652026-05-27T06:46:51Z
dc.title.none.fl_str_mv Multiwavelength observations of Mrk 501 in 2008
title Multiwavelength observations of Mrk 501 in 2008
spellingShingle Multiwavelength observations of Mrk 501 in 2008
MAGIC Collaboration
Raigs gamma
Galàxies actives
Galàxies
Gamma rays
Active galaxies
Galaxies
title_short Multiwavelength observations of Mrk 501 in 2008
title_full Multiwavelength observations of Mrk 501 in 2008
title_fullStr Multiwavelength observations of Mrk 501 in 2008
title_full_unstemmed Multiwavelength observations of Mrk 501 in 2008
title_sort Multiwavelength observations of Mrk 501 in 2008
dc.creator.none.fl_str_mv MAGIC Collaboration
Munar i Adrover, Pere
Paredes i Poy, Josep Maria
Paredes Fortuny, Xavier
Ribó Gomis, Marc
Zanin, Roberta
author MAGIC Collaboration
author_facet MAGIC Collaboration
Munar i Adrover, Pere
Paredes i Poy, Josep Maria
Paredes Fortuny, Xavier
Ribó Gomis, Marc
Zanin, Roberta
author_role author
author2 Munar i Adrover, Pere
Paredes i Poy, Josep Maria
Paredes Fortuny, Xavier
Ribó Gomis, Marc
Zanin, Roberta
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Raigs gamma
Galàxies actives
Galàxies
Gamma rays
Active galaxies
Galaxies
topic Raigs gamma
Galàxies actives
Galàxies
Gamma rays
Active galaxies
Galaxies
description Context. Blazars are variable sources on various timescales over a broad energy range spanning from radio to very high energy (>100 GeV, hereafter VHE). Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its first VHE detection in 1996. However, most of the γ-ray studies performed on Mrk 501 during the past years relate to flaring activity, when the source detection and characterization with the available γ-ray instrumentation was easier toperform. Aims: Our goal is to characterize the source γ-ray emission in detail, together with the radio-to-X-ray emission, during the non-flaring (low) activity, which is less often studied than the occasional flaring (high) activity. Methods: We organized a multiwavelength (MW) campaign on Mrk 501 between March and May 2008. This multi-instrument effort included the most sensitive VHE γ-ray instruments in the northern hemisphere, namely the imaging atmospheric Cherenkov telescopes MAGIC and VERITAS, as well as Swift, RXTE, the F-GAMMA, GASP-WEBT, and other collaborations and instruments. This provided extensive energy and temporal coverage of Mrk 501 throughout the entire campaign. Results: Mrk 501 was found to be in a low state of activity during the campaign, with a VHE flux in the range of 10%-20% of the Crab nebula flux. Nevertheless, significant flux variations were detected with various instruments, with a trend of increasing variability with energy and a tentative correlation between the X-ray and VHE fluxes. The broadband spectral energy distribution during the two different emission states of the campaign can be adequately described within the homogeneous one-zone synchrotron self-Compton model, with the (slightly) higher state described by an increase in the electron number density. Conclusions: The one-zone SSC model can adequately describe the broadband spectral energy distribution of the source during the two months covered by the MW campaign. This agrees with previous studies of the broadband emission of this source during flaring and non-flaring states. We report for the first time a tentative X-ray-to-VHE correlation during such a low VHE activity. Although marginally significant, this positive correlation between X-ray and VHE, which has been reported many times during flaring activity, suggests that the mechanisms that dominate the X-ray/VHE emission during non-flaring-activity are not substantially different from those that are responsible for the emission during flaring activity. The data for Figs. 2 and 5 are only available at the CDS via anonymous ftp to
publishDate 2014
dc.date.none.fl_str_mv 2014
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/69565
url https://hdl.handle.net/2445/69565
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Versió postprint del document publicat a: http://dx.doi.org/10.1051/0004-6361/201322906
Astronomy and Astrophysics, 2014, vol. 573, num. A50, p. 1-12
http://dx.doi.org/10.1051/0004-6361/201322906
dc.rights.none.fl_str_mv (c) Springer Verlag, 2014
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) Springer Verlag, 2014
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Springer Verlag
publisher.none.fl_str_mv Springer Verlag
dc.source.none.fl_str_mv Articles publicats en revistes (Física Quàntica i Astrofísica)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,300724

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