J/A+A/690/A152ivo://CDS.VizieR/J/A+A/690/A152doi:10.26093/cds/vizier.36900152CDSSaeedi S.Sasaki M.Knies J.Robrade J.Heindl T.Zainab A.,Hammerich S.Reh M.Wilms J.2025-02-24T20:01:28Z2024-10-03T08:18:23ZCDS support team

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

cds-question@unistra.frx-ray-sourcesx-ray-binary-starscataclysmic-variable-starsinfrared-photometryvisible-astronomyUsing data from eROSITA(extended Roentgen Survey with an Imaging Telescope Array) on board Spektrum-Roentgen-Gamma (Spektr-RG, SRG) taken during the first eROSITA all-sky survey (eRASS1), we performed the first X-ray classification and population study in the field of the Canis Major overdensity (CMa OD), which is an elliptical-shaped stellar overdensity located at l=-240{deg}; b=-80{deg}. This study aims to identify the X-ray sources in CMa OD. We developed a classification algorithm using multi-wavelength criteria as a preliminary method for the classification of faint X-ray sources, specifically in regions with a high source number density. We used the brightness of the multi-wavelength counterparts (mainly from infrared and optical catalogues), along with the X-ray flux and X-ray hardness ratios (HRs) to classify the sources. Out of a total number of 8311 X-ray sources, we classified 1029 sources as Galactic stars and binaries in the foreground, 946 sources as active galactic nuclei (AGNs) and galaxies in the background, and 435 sources with stellar counterparts that may belong to either the MW or CMa OD. Among the sources with a stellar counterpart, we identified 34 symbiotic star candidates, plus 335 sources, of which the infrared (IR) counterparts have properties of M-giants in CMa OD. Moreover, there is a known high-mass X-ray binary (HMXB, 4U 0728-25) in the field of our study; according to the Gaia parallax of its companion, it appears to be a member of CMa OD. There is also a recently detected transient low-mass X-ray binary (LMXB, SRGt J071522.1-191609) is also present; it may be a member of CMa OD based on its companion, which is most likely highly absorbed and is thus located behind the Galactic disk. In addition, we present the X-ray luminosity function (XLF) of members and candidate members of CMa OD. It is dominated by sources with luminosities of <2x10^32^-10^33^erg/s in the energy range of 0.2-2.3keV. These sources are expected to be either accreting white dwarfs or quiescent LMXBs.2024A&A...690A.152Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A152CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/682/A34 : SRG/eROSITA all-sky survey catalogs (eRASS1) (Merloni+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A152https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A152http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A152https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A152https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A152http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A152GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/690/A152/tablea1 (X-ray sources in the FOV of CMa OD)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/690/A152/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/690/A152/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/690/A152/tablea1?GETtext/xml+votable180.050000true99.63346694-16.761346940.0055555555555555563/620 4/1297 1300 1302 1308-1309 2489 2491-2492 2494 5/5197 5204 5206 5212 5214-5215 9835 9838-9839 9936 9938 9944 9946-9947 9953 9955 9961 9963 6/20741 20784-20785 20787 20796-20797 20799 20820 20822 20828 20830 20852 20854-20855 20885 20887 20964-20965 20976-20977 20980 21546 21632 21634 39334-39335 39337-39339 39346-39347 39350-39351 39400 39402 39511 39517 39519 39780 39782-39783 39808-39809 39811 39817 39819 39841 39843 39896 39898 39920 39922 39928 39930-399318.157980699529898e-21 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/690/A152?format=asciiX-rayOpticalInfrareddefaultJ/A+A/690/A152/tablea1X-ray sources in the FOV of CMa ODrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoSource-ID in this papermeta.idintNameeROSITA ID of the source, 1eRASS JHHMMSS.s-DDMMSSmeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.maine_Pos1 sigma positional error of the sourcearcsecstat.errordoublee_FluxFlux error of the sources in 0.2-5.0keV (in 10^-14^erg/s/cm^-2^ unit)1e-17W.m**-2stat.error;phot.fluxdoubleMLDetection maximum likelihood of source in 0.2-5.0keVstat.likelihood;instr.saturationdoubleHR1Hardness ratio 1 (1)phot.flux;arith.ratiodoublee_HR1Hardness ratio 1 error (1)stat.errordoubleHR2Hardness ratio 2 (1)phot.flux;arith.ratiodoublee_HR2Hardness ratio 2 error (1)stat.errordoubleHR3Hardness ratio 3 (1)phot.flux;arith.ratiodoublee_HR3Hardness ratio 3 error (1)stat.errordoubleHR4Hardness ratio 4 (1)phot.flux;arith.ratiodoublee_HR4Hardness ratio 4 error (1)stat.errordoubleClassClass of a source (2)meta.code.classcharCommentSIMBAD ID of the sources as exist in SIMBAD data base, plus the information is source has the problem of optical loadingmeta.notecharFluxFlux of the sources in 0.2-5.0keV (in 10^-14^erg/s/cm^-2^ unit)1e-17W.m**-2phot.flux;em.X-raydoubleJ/A+A/690/A152/tableb1WISE and Gaia counterpart of X-ray sources in the field of CMa ODrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoSource ID in this papermeta.idintW1mag? WISE W1 magnitude of the infrared counterpart of the X-ray source (1)magphot.mag;em.IR.3-4umdoublenullablee_W1mag? Error of W1 magnitude of the infrared counterpart of the X-ray source (1)magstat.error;phot.magdoublenullableW2mag? WISE W2 magnitude of the infrared counterpart of the X-ray source (1)magphot.mag;em.IR.4-8umdoublenullablee_W2mag? Error of W2 magnitude of the infrared counterpart of the X-ray source (1)magstat.error;phot.magdoublenullableW3mag? WISE W3 magnitude of the infrared counterpart of the X-ray source (1)magphot.flux.density;em.IR.8-15umdoublenullablee_W3mag? Error of W3 magnitude of the infrared counterpart of the X-ray source (1)magstat.error;phot.magdoublenullableW4mag? WISE W4 magnitude of the infrared counterpart of the X-ray source (1)magphot.flux.density;em.IR.15-30umdoublenullablee_W4mag? Error of W4 magnitude of the infrared counterpart of the X-ray source (1)magstat.error;phot.magdoublenullableGmagGaia G magnitude of Gaia counterpart of the X-ray source (1)magphot.mag;em.optdoublee_GmagError of G magnitude of Gaia counterpart of the X-ray source (1)magstat.error;phot.magdoubleRpmagGaia GRP magnitude of Gaia counterpart of the X-ray source (1)magphot.mag;em.opt.Rdoublee_RpmagError of GRP magnitude of Gaia counterpart of the X-ray source (1)magstat.error;phot.magdoubleBpmagGaia GBP magnitude of Gaia counterpart of the X-ray source (1)magphot.mag;em.opt.Bdoublee_BpmagError of GBP magnitude of Gaia counterpart of the X-ray source (1)magstat.error;phot.magdouble