Disentangling multiple high-energy emission components in the Vela X pulsar wind nebula with the $Fermi$ Large Area Telescope
| hal.structure.identifier | Institut de recherche en astrophysique et planétologie [IRAP] | |
| dc.contributor.author | TIBALDO, L. | |
| dc.contributor.author | ZANIN, R. | |
| dc.contributor.author | FAGGIOLI, G. | |
| hal.structure.identifier | Astrophysique Interprétation Modélisation [AIM (UMR7158 / UMR_E_9005 / UM_112)] | |
| dc.contributor.author | BALLET, J. | |
| hal.structure.identifier | Centre d'Etudes Nucléaires de Bordeaux Gradignan [CENBG] | |
| dc.contributor.author | GRONDIN, M.H. | |
| dc.contributor.author | HINTON, J.A. | |
| hal.structure.identifier | Centre d'Etudes Nucléaires de Bordeaux Gradignan [CENBG] | |
| dc.contributor.author | LEMOINE-GOUMARD, M. | |
| dc.date.issued | 2018 | |
| dc.identifier.issn | 0004-6361 | |
| dc.description.abstractEn | Context. 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.iso | en | |
| dc.publisher | EDP Sciences | |
| dc.subject.en | stars: winds | |
| dc.subject.en | outflows | |
| dc.subject.en | gamma rays: stars | |
| dc.subject.en | pulsars | |
| dc.subject.en | individual: PSR J0835–4510 – acceleration of particles | |
| dc.subject.en | radiation mechanisms: non-thermal | |
| dc.subject.en | electron: spectrum | |
| dc.subject.en | gamma ray: emission | |
| dc.subject.en | particle: relativistic | |
| dc.subject.en | power spectrum | |
| dc.subject.en | spectral | |
| dc.subject.en | pulsar | |
| dc.subject.en | X-ray | |
| dc.subject.en | acceleration | |
| dc.subject.en | gap | |
| dc.subject.en | GLAST | |
| dc.subject.en | shock waves | |
| dc.title.en | Disentangling multiple high-energy emission components in the Vela X pulsar wind nebula with the $Fermi$ Large Area Telescope | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.1051/0004-6361/201833356 | |
| dc.subject.hal | Physique [physics]/Astrophysique [astro-ph] | |
| dc.identifier.arxiv | 1806.11499 | |
| bordeaux.journal | Astronomy and Astrophysics - A&A | |
| bordeaux.page | A78 | |
| bordeaux.volume | 617 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-01846720 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Internationale | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-01846720v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&rft.date=2018&rft.volume=617&rft.spage=A78&rft.epage=A78&rft.eissn=0004-6361&rft.issn=0004-6361&rft.au=TIBALDO,%20L.&ZANIN,%20R.&FAGGIOLI,%20G.&BALLET,%20J.&GRONDIN,%20M.H.&rft.genre=article |
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