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hal.structure.identifierInstitut de recherche en astrophysique et planétologie [IRAP]
dc.contributor.authorTIBALDO, L.
dc.contributor.authorZANIN, R.
dc.contributor.authorFAGGIOLI, G.
hal.structure.identifierAstrophysique Interprétation Modélisation [AIM (UMR7158 / UMR_E_9005 / UM_112)]
dc.contributor.authorBALLET, J.
hal.structure.identifierCentre d'Etudes Nucléaires de Bordeaux Gradignan [CENBG]
dc.contributor.authorGRONDIN, M.H.
dc.contributor.authorHINTON, J.A.
hal.structure.identifierCentre d'Etudes Nucléaires de Bordeaux Gradignan [CENBG]
dc.contributor.authorLEMOINE-GOUMARD, M.
dc.date.issued2018
dc.identifier.issn0004-6361
dc.description.abstractEnContext. Vela X is a pulsar wind nebula in which two relativistic particle populations with distinct spatial and spectral distributions dominate the emission at different wavelengths. An extended 2° × 3°nebula is seen in radio and GeV gamma rays. An elongated cocoon prevails in X-rays and TeV gamma rays.Aims. We use ~9.5 yr of data from the Fermi Large Area Telescope (LAT) to disentangle gamma-ray emission from the two components in the energy range from 10 GeV to 2 TeV, bridging the gap between previous measurements at GeV and TeV energies.Methods. We determine the morphology of emission associated to Vela X separately at energies <100 and >100 GeV, and compare it to the morphology seen at other wavelengths. Then, we derive the spectral energy distribution of the two gamma-ray components over the full energy range.Results. The best overall fit to the LAT data is provided by the combination of the two components derived at energies <100 and >100 GeV. The first component has a soft spectrum, spectral index 2.19 ± 0.16−0.22+0.05, and extends over a region of radius 1.°36±0.°04, consistent with the size of the radio nebula. The second component has a harder spectrum, spectral index0.9 ± 0.3−0.1+0.3, and is concentrated over an area of radius 0.°63±0.°03, coincident with the X-ray cocoon that had already been established as accounting for the bulk of the emission at TeV energies.Conclusions. The spectrum measured for the low-energy component corroborates previous evidence for a roll-over of the electron spectrum in the extended radio nebula at energies of a few tens of GeV possibly due to diffusive escape. The high-energy component has a very hard spectrum: if the emission is produced by electrons with a power-law spectrum, the electrons must be uncooled, and there is a hint that their spectrum may be harder than predictions by standard models of Fermi acceleration at relativistic shocks.
dc.language.isoen
dc.publisherEDP Sciences
dc.subject.enstars: winds
dc.subject.enoutflows
dc.subject.engamma rays: stars
dc.subject.enpulsars
dc.subject.enindividual: PSR J0835–4510 – acceleration of particles
dc.subject.enradiation mechanisms: non-thermal
dc.subject.enelectron: spectrum
dc.subject.engamma ray: emission
dc.subject.enparticle: relativistic
dc.subject.enpower spectrum
dc.subject.enspectral
dc.subject.enpulsar
dc.subject.enX-ray
dc.subject.enacceleration
dc.subject.engap
dc.subject.enGLAST
dc.subject.enshock waves
dc.title.enDisentangling multiple high-energy emission components in the Vela X pulsar wind nebula with the $Fermi$ Large Area Telescope
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/201833356
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]
dc.identifier.arxiv1806.11499
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageA78
bordeaux.volume617
bordeaux.peerReviewedoui
hal.identifierhal-01846720
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-01846720v1
bordeaux.COinSctx_ver=Z39.88-2004&amp;rft_val_fmt=info:ofi/fmt:kev:mtx:journal&amp;rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&amp;rft.date=2018&amp;rft.volume=617&amp;rft.spage=A78&amp;rft.epage=A78&amp;rft.eissn=0004-6361&amp;rft.issn=0004-6361&amp;rft.au=TIBALDO,%20L.&amp;ZANIN,%20R.&amp;FAGGIOLI,%20G.&amp;BALLET,%20J.&amp;GRONDIN,%20M.H.&amp;rft.genre=article


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