J/A+A/625/A99ivo://CDS.VizieR/J/A+A/625/A99doi:10.26093/cds/vizier.36250099CDSBenaglia P.del Palacio S.Ishwara-Chandra C.H.De Becker M.,Isequilla N.L.Saponara J.2019-06-06T06:38:41Z2019-05-23T14:12:06ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frradio-sourcesradio-astronomywolf-rayet-starsThe massive binary system WR 11 ({gamma}^2^-Velorum) has recently been proposed as the counterpart of a Fermi source. If this association is correct, this system would be the second colliding wind binary detected in GeV {gamma}-rays. However, the reported flux measurements from 1.4 to 8.64 GHz fail to establish the presence of nonthermal (synchrotron) emission from this source. Moreover, WR 11 is not the only radio source within the Fermi detection box. Other possible counterparts have been identified in archival data, some of which present strong nonthermal radio emission. We conducted arcsec-resolution observations toward WR 11 at very low frequencies (150-1400 MHz) where the nonthermal emission - if existent and not absorbed - is expected to dominate. We present a catalog of more than 400 radio emitters, among which a significant portion are detected at more than one frequency, including limited spectral index information. Twenty-one of these radio emitters are located within the Fermi significant emission. A search for counterparts for this last group pointed at MOST 0808-471; this source is 2' away from WR 11 and is a promising candidate for high-energy emission, having a resolved structure along 325-1390 MHz. For this source, we reprocessed archive interferometric data up to 22.3 GHz and obtained a nonthermal radio spectral index of -0.97+/-0.09. However, multiwavelength observations of this source are required to establish its nature and to assess whether it can produce (part of) the observed {gamma}-rays. WR 11 spectrum follows a spectral index of 0.74+/-0.03 from 150 to 230 GHz, consistent with thermal emission. We interpret that any putative synchrotron radiation from the colliding-wind region of this relatively short-period system is absorbed in the photospheres of the individual components. Notwithstanding, the new radio data allowed us to derive a mass-loss rate of 2.5x10^-5^ M_{sun}_/yr, which, according to the latest models for {gamma}-ray emission in WR 11, would suffice to provide the required kinetic power to feed nonthermal radiation processes.2019A&A...625A..99Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/625/A99CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/625/A99https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/625/A99http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/625/A99https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/625/A99https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/625/A99http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/625/A99GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/625/A99/table4 (Sources detected at 150, 325 and 610MHz)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/625/A99/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/625/A99/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/625/A99/table4?GETtext/xml+votable180.050000true125.264583-47.6013890.0055555555555555565/9798 9801 9804 6/39181 39183 39196 39198 39212-39213 39220 39224-39225https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/625/A99?format=asciiRadiodefaultJ/A+A/625/A99/table4Sources detected at 150, 325 and 610MHzrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMACSMACS designation (GNNN-NNN), where GNNN indicates the observed bandmeta.id;meta.maincharRAJ2000Right Ascension (J2000, Epoch 2000)pos.eq.ra;meta.maine_RAJ2000Mean error on RAssstat.error;pos.eq.rafloatDEJ2000Declination (J2000, Epoch 2000)pos.eq.dec;meta.maine_DEJ2000Mean error on DEsarcsecstat.error;pos.eq.decfloatSIntegrated flux density of radio sourcemJyphot.flux.density;em.radiodoublee_SMean error on SmJystat.errorfloatBSPeak flux density of radio sourcemJyphot.flux.density;em.radiodoublee_BSMean error on BSmJystat.errorfloatRABRAh maxima valuepos.eq.rae_RABMean error on BRAssstat.error;pos.eq.rafloatDEBDEd maxima valuepos.eq.dece_DEBMean error on B_DEsarcsecstat.error;pos.eq.decfloatBmajBeam major axisarcsecphys.angSizefloate_BmajMean error on major axisarcsecstat.errorfloatBminBeam minor axisarcsecphys.angSize;srcfloate_BminMean error on minor axisarcsecstat.errorfloatbPABeam position angledegpos.posAng;instr.beamfloate_bPAMean error on beam position angledegstat.errorfloatBandRadio band for the flux (150, 325 or 610)MHzinstr.bandpassint