Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission
Aims. We present the results of a deep spectral analysis of all Swift observations of Mrk 421 between April 2006 and July 2006, when it reached its highest X-ray flux recorded until the end of 2006. The peak flux was about 85 milli-Crab in the 2.0–10.0 keV band, and the peak energy (Ep) of the spe...
Gespeichert in:
Veröffentlicht in: | Astronomy and astrophysics (Berlin) 2009-07, Vol.501 (3), p.879-898 |
---|---|
Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
container_end_page | 898 |
---|---|
container_issue | 3 |
container_start_page | 879 |
container_title | Astronomy and astrophysics (Berlin) |
container_volume | 501 |
creator | Tramacere, A. Giommi, P. Perri, M. Verrecchia, F. Tosti, G. |
description | Aims. We present the results of a deep spectral analysis of all Swift observations of Mrk 421 between April 2006 and July 2006, when it reached its highest X-ray flux recorded until the end of 2006. The peak flux was about 85 milli-Crab in the 2.0–10.0 keV band, and the peak energy (Ep) of the spectral energy distribution (SED) was often at energies higher than 10 keV. We study trends between the spectral parameters, and the physical insights the parameters provide into the underlying acceleration and emission mechanisms. Methods. We performed a spectral analysis of Swift observations to investigate trends between the spectral parameters. We searched for acceleration and energetic features phenomenologically linked to the SSC model parameters, by predicting their effects in the γ-ray band, and in particular, the spectral shape expected in the Fermi Gamma-ray Space Telescope-LAT band. Results. We confirm that the X-ray spectrum is described well by a log-parabolic distribution close to Ep, that the peak flux of the SED (Sp) is correlated with Ep, and that Ep is anti-correlated with the curvature parameter (b). The spectral evolution in the Hardness-ratio-flux plane shows both clockwise and counter-clockwise patterns. During the most energetic flares, the UV-to-soft-X-ray spectral shape requires an electron distribution spectral index of $s\simeq 2.3$. Conclusions. We demonstrate that the UV-to-X-ray emission from Mrk 421 is probably generated by a population of electrons that is actually curved, and has a low energy power-law tail. The observed spectral curvature is consistent with both stochastic acceleration or energy-dependent acceleration probability mechanisms, whereas the power-law slope of XRT-UVOT data is close to that inferred from the GRBs X-ray afterglow and in agreement with the universal first-order relativistic shock acceleration models. This scenario implies that magnetic turbulence may play a twofold role: spatial diffusion relevant to the first order process and momentum diffusion relevant to the second order process. |
doi_str_mv | 10.1051/0004-6361/200810865 |
format | Article |
fullrecord | <record><control><sourceid>istex_cross</sourceid><recordid>TN_cdi_crossref_primary_10_1051_0004_6361_200810865</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>ark_67375_80W_DGH51SFS_7</sourcerecordid><originalsourceid>FETCH-LOGICAL-c362t-4b1bfbabbdeebf2fe9399f3218023f87659900ee8d2bcc3a5a3069a3e26cc27e3</originalsourceid><addsrcrecordid>eNo9kEtOwzAQhi0EEuVxAjbesEzrR-IkS8SjIFGBVChLy3HGYEiTynYLvQ1rjsHJcFrUhTX2zPfPeH6EzigZUpLRESEkTQQXdMQIKSgpRLaHBjTlLCF5KvbRYEccoiPv3-OT0YIP0M_005qAu8qDW6lgu9bjzuDwBngFbo1tG6D1gE2jnG1fsdLBrmxY99DEffx-p4ziermpxdliiO-G-PEN2m4eT9O9Wq0avLA6LB30ImhAB9e1sZOOd7eZiVVb44WDOnKbL5jO4QnMRmOYYZhb72P2BB0Y1Xg4_Y_H6Pnm-unyNrl_GN9dXtwnmgsWkrSilalUVdUAlWEGSl6Whsd1CeOmyEVWloQAFDWrtOYqU5yIUnFgQmuWAz9GfNtXu857B0YunJ0rt5aUyN5u2ZspezPlzu6oOt-qFsrHlY1TrbZ-J2U0z1he8sglW876AF-7unIfUuQ8z2RBXuTV-Daj05upzPkfIfOSKA</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype></control><display><type>article</type><title>Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission</title><source>Bacon EDP Sciences France Licence nationale-ISTEX-PS-Journals-PFISTEX</source><source>EDP Sciences</source><source>EZB-FREE-00999 freely available EZB journals</source><creator>Tramacere, A. ; Giommi, P. ; Perri, M. ; Verrecchia, F. ; Tosti, G.</creator><creatorcontrib>Tramacere, A. ; Giommi, P. ; Perri, M. ; Verrecchia, F. ; Tosti, G.</creatorcontrib><description>Aims. We present the results of a deep spectral analysis of all Swift observations of Mrk 421 between April 2006 and July 2006, when it reached its highest X-ray flux recorded until the end of 2006. The peak flux was about 85 milli-Crab in the 2.0–10.0 keV band, and the peak energy (Ep) of the spectral energy distribution (SED) was often at energies higher than 10 keV. We study trends between the spectral parameters, and the physical insights the parameters provide into the underlying acceleration and emission mechanisms. Methods. We performed a spectral analysis of Swift observations to investigate trends between the spectral parameters. We searched for acceleration and energetic features phenomenologically linked to the SSC model parameters, by predicting their effects in the γ-ray band, and in particular, the spectral shape expected in the Fermi Gamma-ray Space Telescope-LAT band. Results. We confirm that the X-ray spectrum is described well by a log-parabolic distribution close to Ep, that the peak flux of the SED (Sp) is correlated with Ep, and that Ep is anti-correlated with the curvature parameter (b). The spectral evolution in the Hardness-ratio-flux plane shows both clockwise and counter-clockwise patterns. During the most energetic flares, the UV-to-soft-X-ray spectral shape requires an electron distribution spectral index of $s\simeq 2.3$. Conclusions. We demonstrate that the UV-to-X-ray emission from Mrk 421 is probably generated by a population of electrons that is actually curved, and has a low energy power-law tail. The observed spectral curvature is consistent with both stochastic acceleration or energy-dependent acceleration probability mechanisms, whereas the power-law slope of XRT-UVOT data is close to that inferred from the GRBs X-ray afterglow and in agreement with the universal first-order relativistic shock acceleration models. This scenario implies that magnetic turbulence may play a twofold role: spatial diffusion relevant to the first order process and momentum diffusion relevant to the second order process.</description><identifier>ISSN: 0004-6361</identifier><identifier>EISSN: 1432-0746</identifier><identifier>DOI: 10.1051/0004-6361/200810865</identifier><identifier>CODEN: AAEJAF</identifier><language>eng</language><publisher>Les Ulis: EDP Sciences</publisher><subject>acceleration of particles ; Astronomy ; Earth, ocean, space ; Exact sciences and technology ; galaxies: active ; galaxies: BL Lacertae objects: individual: Mrk 421 ; radiation mechanisms: non-thermal ; X-rays: individuals: Mrk 421</subject><ispartof>Astronomy and astrophysics (Berlin), 2009-07, Vol.501 (3), p.879-898</ispartof><rights>2009 INIST-CNRS</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c362t-4b1bfbabbdeebf2fe9399f3218023f87659900ee8d2bcc3a5a3069a3e26cc27e3</citedby><cites>FETCH-LOGICAL-c362t-4b1bfbabbdeebf2fe9399f3218023f87659900ee8d2bcc3a5a3069a3e26cc27e3</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><link.rule.ids>314,780,784,3727,27924,27925</link.rule.ids><backlink>$$Uhttp://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=21752793$$DView record in Pascal Francis$$Hfree_for_read</backlink></links><search><creatorcontrib>Tramacere, A.</creatorcontrib><creatorcontrib>Giommi, P.</creatorcontrib><creatorcontrib>Perri, M.</creatorcontrib><creatorcontrib>Verrecchia, F.</creatorcontrib><creatorcontrib>Tosti, G.</creatorcontrib><title>Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission</title><title>Astronomy and astrophysics (Berlin)</title><description>Aims. We present the results of a deep spectral analysis of all Swift observations of Mrk 421 between April 2006 and July 2006, when it reached its highest X-ray flux recorded until the end of 2006. The peak flux was about 85 milli-Crab in the 2.0–10.0 keV band, and the peak energy (Ep) of the spectral energy distribution (SED) was often at energies higher than 10 keV. We study trends between the spectral parameters, and the physical insights the parameters provide into the underlying acceleration and emission mechanisms. Methods. We performed a spectral analysis of Swift observations to investigate trends between the spectral parameters. We searched for acceleration and energetic features phenomenologically linked to the SSC model parameters, by predicting their effects in the γ-ray band, and in particular, the spectral shape expected in the Fermi Gamma-ray Space Telescope-LAT band. Results. We confirm that the X-ray spectrum is described well by a log-parabolic distribution close to Ep, that the peak flux of the SED (Sp) is correlated with Ep, and that Ep is anti-correlated with the curvature parameter (b). The spectral evolution in the Hardness-ratio-flux plane shows both clockwise and counter-clockwise patterns. During the most energetic flares, the UV-to-soft-X-ray spectral shape requires an electron distribution spectral index of $s\simeq 2.3$. Conclusions. We demonstrate that the UV-to-X-ray emission from Mrk 421 is probably generated by a population of electrons that is actually curved, and has a low energy power-law tail. The observed spectral curvature is consistent with both stochastic acceleration or energy-dependent acceleration probability mechanisms, whereas the power-law slope of XRT-UVOT data is close to that inferred from the GRBs X-ray afterglow and in agreement with the universal first-order relativistic shock acceleration models. This scenario implies that magnetic turbulence may play a twofold role: spatial diffusion relevant to the first order process and momentum diffusion relevant to the second order process.</description><subject>acceleration of particles</subject><subject>Astronomy</subject><subject>Earth, ocean, space</subject><subject>Exact sciences and technology</subject><subject>galaxies: active</subject><subject>galaxies: BL Lacertae objects: individual: Mrk 421</subject><subject>radiation mechanisms: non-thermal</subject><subject>X-rays: individuals: Mrk 421</subject><issn>0004-6361</issn><issn>1432-0746</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2009</creationdate><recordtype>article</recordtype><recordid>eNo9kEtOwzAQhi0EEuVxAjbesEzrR-IkS8SjIFGBVChLy3HGYEiTynYLvQ1rjsHJcFrUhTX2zPfPeH6EzigZUpLRESEkTQQXdMQIKSgpRLaHBjTlLCF5KvbRYEccoiPv3-OT0YIP0M_005qAu8qDW6lgu9bjzuDwBngFbo1tG6D1gE2jnG1fsdLBrmxY99DEffx-p4ziermpxdliiO-G-PEN2m4eT9O9Wq0avLA6LB30ImhAB9e1sZOOd7eZiVVb44WDOnKbL5jO4QnMRmOYYZhb72P2BB0Y1Xg4_Y_H6Pnm-unyNrl_GN9dXtwnmgsWkrSilalUVdUAlWEGSl6Whsd1CeOmyEVWloQAFDWrtOYqU5yIUnFgQmuWAz9GfNtXu857B0YunJ0rt5aUyN5u2ZspezPlzu6oOt-qFsrHlY1TrbZ-J2U0z1he8sglW876AF-7unIfUuQ8z2RBXuTV-Daj05upzPkfIfOSKA</recordid><startdate>20090701</startdate><enddate>20090701</enddate><creator>Tramacere, A.</creator><creator>Giommi, P.</creator><creator>Perri, M.</creator><creator>Verrecchia, F.</creator><creator>Tosti, G.</creator><general>EDP Sciences</general><scope>BSCLL</scope><scope>IQODW</scope><scope>AAYXX</scope><scope>CITATION</scope></search><sort><creationdate>20090701</creationdate><title>Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission</title><author>Tramacere, A. ; Giommi, P. ; Perri, M. ; Verrecchia, F. ; Tosti, G.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c362t-4b1bfbabbdeebf2fe9399f3218023f87659900ee8d2bcc3a5a3069a3e26cc27e3</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2009</creationdate><topic>acceleration of particles</topic><topic>Astronomy</topic><topic>Earth, ocean, space</topic><topic>Exact sciences and technology</topic><topic>galaxies: active</topic><topic>galaxies: BL Lacertae objects: individual: Mrk 421</topic><topic>radiation mechanisms: non-thermal</topic><topic>X-rays: individuals: Mrk 421</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Tramacere, A.</creatorcontrib><creatorcontrib>Giommi, P.</creatorcontrib><creatorcontrib>Perri, M.</creatorcontrib><creatorcontrib>Verrecchia, F.</creatorcontrib><creatorcontrib>Tosti, G.</creatorcontrib><collection>Istex</collection><collection>Pascal-Francis</collection><collection>CrossRef</collection><jtitle>Astronomy and astrophysics (Berlin)</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Tramacere, A.</au><au>Giommi, P.</au><au>Perri, M.</au><au>Verrecchia, F.</au><au>Tosti, G.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission</atitle><jtitle>Astronomy and astrophysics (Berlin)</jtitle><date>2009-07-01</date><risdate>2009</risdate><volume>501</volume><issue>3</issue><spage>879</spage><epage>898</epage><pages>879-898</pages><issn>0004-6361</issn><eissn>1432-0746</eissn><coden>AAEJAF</coden><abstract>Aims. We present the results of a deep spectral analysis of all Swift observations of Mrk 421 between April 2006 and July 2006, when it reached its highest X-ray flux recorded until the end of 2006. The peak flux was about 85 milli-Crab in the 2.0–10.0 keV band, and the peak energy (Ep) of the spectral energy distribution (SED) was often at energies higher than 10 keV. We study trends between the spectral parameters, and the physical insights the parameters provide into the underlying acceleration and emission mechanisms. Methods. We performed a spectral analysis of Swift observations to investigate trends between the spectral parameters. We searched for acceleration and energetic features phenomenologically linked to the SSC model parameters, by predicting their effects in the γ-ray band, and in particular, the spectral shape expected in the Fermi Gamma-ray Space Telescope-LAT band. Results. We confirm that the X-ray spectrum is described well by a log-parabolic distribution close to Ep, that the peak flux of the SED (Sp) is correlated with Ep, and that Ep is anti-correlated with the curvature parameter (b). The spectral evolution in the Hardness-ratio-flux plane shows both clockwise and counter-clockwise patterns. During the most energetic flares, the UV-to-soft-X-ray spectral shape requires an electron distribution spectral index of $s\simeq 2.3$. Conclusions. We demonstrate that the UV-to-X-ray emission from Mrk 421 is probably generated by a population of electrons that is actually curved, and has a low energy power-law tail. The observed spectral curvature is consistent with both stochastic acceleration or energy-dependent acceleration probability mechanisms, whereas the power-law slope of XRT-UVOT data is close to that inferred from the GRBs X-ray afterglow and in agreement with the universal first-order relativistic shock acceleration models. This scenario implies that magnetic turbulence may play a twofold role: spatial diffusion relevant to the first order process and momentum diffusion relevant to the second order process.</abstract><cop>Les Ulis</cop><pub>EDP Sciences</pub><doi>10.1051/0004-6361/200810865</doi><tpages>20</tpages><oa>free_for_read</oa></addata></record> |
fulltext | fulltext |
identifier | ISSN: 0004-6361 |
ispartof | Astronomy and astrophysics (Berlin), 2009-07, Vol.501 (3), p.879-898 |
issn | 0004-6361 1432-0746 |
language | eng |
recordid | cdi_crossref_primary_10_1051_0004_6361_200810865 |
source | Bacon EDP Sciences France Licence nationale-ISTEX-PS-Journals-PFISTEX; EDP Sciences; EZB-FREE-00999 freely available EZB journals |
subjects | acceleration of particles Astronomy Earth, ocean, space Exact sciences and technology galaxies: active galaxies: BL Lacertae objects: individual: Mrk 421 radiation mechanisms: non-thermal X-rays: individuals: Mrk 421 |
title | Swift observations of the very intense flaring activity of Mrk 421 during 2006. I. Phenomenological picture of electron acceleration and predictions for MeV/GeV emission |
url | https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2024-12-23T11%3A22%3A06IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-istex_cross&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Swift%20observations%20of%20the%20very%20intense%20flaring%20activity%20of%20Mrk%C2%A0421%20during%202006.%20I.%20Phenomenological%20picture%20of%20electron%20acceleration%20and%20predictions%20for%20MeV/GeV%20emission&rft.jtitle=Astronomy%20and%20astrophysics%20(Berlin)&rft.au=Tramacere,%20A.&rft.date=2009-07-01&rft.volume=501&rft.issue=3&rft.spage=879&rft.epage=898&rft.pages=879-898&rft.issn=0004-6361&rft.eissn=1432-0746&rft.coden=AAEJAF&rft_id=info:doi/10.1051/0004-6361/200810865&rft_dat=%3Cistex_cross%3Eark_67375_80W_DGH51SFS_7%3C/istex_cross%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_id=info:pmid/&rfr_iscdi=true |