J/ApJ/554/202ivo://CDS.VizieR/J/ApJ/554/202doi:10.26093/cds/vizier.15540202CDSImmler S.Wang Q.D.2001-12-31T15:27:45Z2001-12-31T16:27:36ZCDS support team

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

cds-question@unistra.frx-ray-sourcesradio-sourcesWe present results from the analysis of deep ROSAT HRI and PSPC observations of the spiral galaxy M81. The inferred total (0.5-2keV band) luminosity of M81 is ~3x10^40^ergs/s, excluding the contribution from identified interlopers found within the D_25_ ellipse. The nucleus of the galaxy alone accounts for about 65% of this luminosity. The rest is due to 26 other X-ray sources (contributing ~10%) and to apparently diffuse emission, which is seen across much of the galactic disk and is particularly bright in the bulge region around the nucleus. Spectral analysis further gives evidence for a soft component, which can be characterized by a two-temperature optically thin plasma with temperature at ~0.15 and 0.60keV and an absorption of the galactic foreground only. These components, accounting for ~13% of the X-ray emission from the region, apparently arise in a combination of hot gas and faint discrete sources. We find interesting spatial coincidences of luminous (10^37^-10^40^ergs/s) and variable X-ray sources with shock-heated optical nebulae. Three of them are previously classified as supernova remnant candidates. The other one is far off the main body of M81 but is apparently associated with a dense H I concentration produced most likely by the tidal interactions of the galaxy with its companions. These associations suggest that such optical nebulae may be powered by outflows from luminous X-ray binaries, which are comparable to, or more luminous than, Galactic "microquasars."2001ApJ...554..202Ihttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/554/202CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIX/28 : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 2000)IX/30 : Second ROSAT PSPC Catalog (ROSAT, 2000)IX/31 : The WGACAT version of ROSAT sources (White+ 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/554/202https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/554/202http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/554/202https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/554/202https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/554/202http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/554/202GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/554/202/table3 (ROSAT HRI M81 source list)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/554/202/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/554/202/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/554/202/table3?GETtext/xml+votable180.050000true148.171458369.04555560.005555555555555556Cone search capability for table J/ApJ/554/202/table4 (ROSAT PSPC M81 source list)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/554/202/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/554/202/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/554/202/table4?GETtext/xml+votable180.050000true148.17041769.0638890.005555555555555556Cone search capability for table J/ApJ/554/202/table6 (Position Coincidence between X-Ray sources and SNR candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/554/202/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/554/202/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/554/202/table6?GETtext/xml+votable180.050000true148.7137569.0495830.0055555555555555566/7603 7606https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/554/202?format=asciiX-rayRadiodefaultJ/ApJ/554/202/table3ROSAT HRI M81 source listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHNNSource name (where H denotes HRI) (G1)meta.id;meta.maincharprimaryRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainR90%The 90% confidence error radius of the source position (1)arcsecstat.errorfloatCRNet count rate (2)phot.count;em.X-rayfloate_CRUncertainty in CR (2)stat.errorfloatComComment regarding source variabilitymeta.notecharJ/ApJ/554/202/table4ROSAT PSPC M81 source liste_HR1Uncertainty in HR1stat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPNNSource name (where `P' denotes PSPC) (G1)meta.id;meta.maincharprimaryRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainCRNet count rate in the 0.5-2keV bandct/ksphot.count;em.X-rayfloate_CRUncertainty in CRct/ksstat.errorfloatHR1First hardness ratio (1)phot.flux;arith.ratiofloatHR2Second hardness ratio (2)phot.flux;arith.ratiofloate_HR2Uncertainty in HR2stat.errorfloatComFurther HRI source positional coincidences and variability commentsmeta.notecharJ/ApJ/554/202/table5ROSAT M81 source identificationsIdIdentification (1)meta.idcharl_B-RLimit flag on B-Rmeta.code.errorcharBmag? B magnitudemagphot.mag;em.opt.BfloatnullableB-R? B-R colour indexmagphot.color;em.opt.B;em.opt.RfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHNNHRI ROSAT name (HNN) (G1)meta.id;meta.maincharPNNPSPC ROSAT Name (PNN) (G1)meta.id;meta.maincharOffsetOffset from the X-ray positionarcsecpos.angDistancefloatRmag? R magnitudemagphot.mag;em.opt.RfloatnullableJ/ApJ/554/202/table6Position Coincidence between X-Ray sources and SNR candidatesSizeSizepcphys.size.diameterintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[MF97]SNR designation (MF NN = [MF97] M 81 NN in Simbad)meta.idcharRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainOffsetOffset between X-ray and optical positionsarcsecpos.angDistancefloatLHaH{alpha} luminosityWphys.luminosityfloat[SII]/HaRatio of [SII] to H{alpha}spect.line.intensity;arith.ratiofloatOptOptical shapesrc.classcharHNNHRI ROSAT source name (G1)meta.id;meta.maincharPNNPSPC ROSAT source name (G1)meta.id.part;meta.maincharLXX-ray luminosityWphys.luminosity;em.X-rayfloat