J/A+A/594/A82ivo://CDS.VizieR/J/A+A/594/A82doi:10.26093/cds/vizier.35940082CDSRauw G.Naze Y.2018-08-31T08:14:43Z2016-10-14T09:08:02ZCDS support team

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

cds-question@unistra.fropen-star-clustersx-ray-sourcesVery young open clusters are ideal places to study the X-ray properties of a homogeneous population of early-type stars. In this respect, the IC 1805 open cluster is very interesting as it hosts the O4 If+ star HD 15570 thought to be in an evolutionary stage intermediate between a normal O-star and a Wolf-Rayet star. Such a star could provide a test for theoretical models aiming at explaining the empirical scaling relation between the X-ray and bolometric luminosities of O-type stars. We have observed IC 1805 with XMM-Newton and further collected optical spectroscopy of some of the O-star members of the cluster. The optical spectra allow us to revisit the orbital solutions of BD+60 497 and HD 15558, and provide the first evidence of binarity for BD+60 498. X-ray emission from colliding winds does not appear to play an important role among the O-stars of IC 1805. Notably, the X-ray fluxes do not vary significantly between archival X-ray observations and our XMM-Newton pointing. The very fast rotator BD+60 513, and to a lesser extent the O4 If+ star HD 15570 appear somewhat underluminous. Whilst the underluminosity of HD 15570 is only marginally significant, its amplitude is found to be compatible with theoretical expectations based on its stellar and wind properties. A number of other X-ray sources are detected in the field, and the brightest objects, many of which are likely low-mass pre-main sequence stars, are analyzed in detail.2016A&A...594A..82Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/594/A82CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIX/46 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR5 (XMM-SSC, 2016)J/ApJ/726/19 : Intermediate-mass stars in IC 1805 (Wolff+, 2011)J/A+A/554/A3 : Vilnius photometry of IC 1805 stars (Straizys+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/594/A82https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/594/A82http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/594/A82https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/594/A82https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/594/A82http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/594/A82GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/594/A82/tablea1 (List of X-ray sources detected with XMM-Newton in IC 1805)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/594/A82/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/594/A82/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/594/A82/tablea1?GETtext/xml+votable180.050000true37.666137561.497116670.0055555555555555566/3307 3310https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/594/A82?format=asciiX-raydefaultJ/A+A/594/A82/tablea1List of X-ray sources detected with XMM-Newton in IC 1805recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameDesignation of the source according to the IAU convention for XMM-Newton sources (JHHMMSS.s+DDMMSS)meta.id;meta.maincharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainXIDSource number ordered by decreasing fluxmeta.idintu_XIDUncertainty flag on XDI (1)meta.code.errorcharCRMOS1? EPIC-MOS1 count rate0.001count.s**-1phot.count;em.X-rayfloatnullablee_CRMOS1? rms uncertainty on CRMOS10.001count.s**-1stat.errorfloatnullableHRMOS1? EPIC-MOS1 hardness ratio (2)phot.flux;arith.ratiofloatnullablee_HRMOS1? rms uncertainty on HRMOS1stat.errorfloatnullableCRMOS2? EPIC-MOS2 count rate0.001count.s**-1phot.count;em.X-rayfloatnullablee_CRMOS2? rms uncertainty on CRMOS20.001count.s**-1stat.errorfloatnullableHRMOS2? EPIC-MOS2 hardness ratio (2)phot.flux;arith.ratiofloatnullablee_HRMOS2? rms uncertainty on HRMOS2stat.errorfloatnullableCRPN? EPIC-pn count rate0.001count.s**-1phot.count;em.X-rayfloatnullablee_CRPN? rms uncertainty on CRPN0.001count.s**-1stat.errorfloatnullableHRPN? EPIC-pn hardness ratio (2)phot.flux;arith.ratiofloatnullablee_HRPN? rms uncertainty on HRPNstat.errorfloatnullableONameOptical counterpart (3)meta.id.crosscharSpTypespectral type of optical counterpart (4)src.spTypecharNoteNotes to bibliographic reference for spectral types (5)meta.notechar3XMMDisplay the 3XMM-DR6 data within 15" (XMM-SSC 2016, Cat. IX/50)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar