J/MNRAS/544/885ivo://CDS.VizieR/J/MNRAS/544/885CDSMaan V.Katira A.Mooley K.2026-01-23T19:01:44Z2025-11-03T19:11:14ZCDS support team

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

cds-question@unistra.frsurveysx-ray-sourcesAlthough a multitude of studies have focused on targeted observations of Galactic X-ray transients, blind surveys and population studies have been limited. We have used the ROSAT, eROSITA and Gaia source catalogs to find Galactic X-ray transients having timescales <30 years. We report the properties of 738 transients found in our search, majority of which are active stars or interacting binaries. We have also found ~40 compact object systems among which are at least 8 newly-identified white-dwarf systems, 3 known X-ray binaries, and one known pulsar. We use eROSITA (soft X-ray) spectra of the Galactic transients to show that two distinct types of flaring systems are prevalent: one having peak around 1keV, well fit by thermal models, and another having peak below 0.2keV and requiring a power-law component. Our study also reveals that single star or interacting binary systems (X-ray transients) involving giant stars exhibit significantly higher X-ray luminosities than systems involving only main-sequence stars or young stellar objects. Finally, we discuss the properties of the transients in the context of their putative emission mechanisms, the fraction of transients with respect to the total population, and the rates of Galactic transients expected in blind searches of the X-ray sky.2025MNRAS.544..885Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/544/885CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/588/A103 : Second ROSAT all-sky survey (2RXS) source catalogJ/A+A/682/A34 : SRG/eROSITA all-sky survey catalogs (eRASS1) (Merloni+, 2024)J/A+A/693/A62 : eRO-ExTra catalog (Grotova+, 2025)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/544/885https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/544/885http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/544/885https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/544/885https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/544/885http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/544/885GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/544/885/ero-g-t (Catalogue of eRASS1 Galactic transients (updated version, 23-Jan-2026))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/544/885/ero-g-t?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/544/885/ero-g-t?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/544/885/ero-g-t?GETtext/xml+votable180.050000true80.3160519412625.225423301990.0055555555555555565/10775 6/4280 4348 4376 4461 4493 4691 4743 4783 5193 5210 5382 6148 6187 6208 6266 6355 6422 10250 16449 16451 16461 20581 20589 20657 20681 20797 20847 20895 20922 20926 20940 20943 20950-20951 20979 21004 21007 21050 21069 21131 21142 21155 21365 21370 21377 21394 21416 21422 21432-21433 21435-21436 21438-21439 21442 21482 21574 21670 21728 21775 21820 21828 21903 22018 22050 22234-22235 22269 22334 22692 22731 22734 22800 22804-22805 22839 22844 22851 22854 22862 22866 22875 22881-22882 22885 22892 22924 22934 22943 22977 22985 23001 23027 23082 23118 23138 23156 23372 23393 23412 23423 23518 23526 23582 23637 23652 23654 23675 23704 23730 23820 23872 23924 24021 24051 24062 24121 24145 24164 24169 24179 24188 24205 24283 24354 24359-24360 24412 24623 24707 24717 24793 24800 24923 25090 25223 25235 25269 25408 25456 25651 25709 25950 25966 26045 26277 26481 26563 26608 26751 26950 27263 27496 27592 27610 27908 27992 28286 28316 28400 28483 28515 28587 28678 28690 28694 28696 28705 28807 28818 29194 29222 32799 32831 32886 32993 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47845https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/544/885?format=asciiX-raydefaultJ/MNRAS/544/885/ero-g-tCatalogue of eRASS1 Galactic transients (updated version, 23-Jan-2026)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIAUNameString containing the official IAU name of the source (1eRASS JHHMMSS.s+DDMMSS)meta.id;meta.maincharRA_ICRSBarycentric right ascension (ICRS) at Ep=2015.5 (1)degpos.eq.ra;meta.mainDE_ICRSBarycentric declination (ICRS) at Ep=2015.5 (1)degpos.eq.dec;meta.maine_RA_ICRSStandard error of right ascension (1)masstat.error;pos.eq.rafloate_DE_ICRSStandard error of declination (1)masstat.error;pos.eq.decfloatFeRASS1eRASS1 flux in 0.2-2.3 keV bandmW.m**-2phot.flux;em.X-raydoublee_FeRASS11-sigma combined error on eRASS1 flux in 0.2-2.3keV bandmW.m**-2stat.errordoubleF2RXS? 2RXS (ROSAT) flux in 0.1-2.4keV band (2)mW.m**-2phot.flux;em.X-raydoublenullableDistDistancepcpos.distanceinte_F2RXS? Error on 2RXS flux in 0.1-2.4keV band (2)mW.m**-2stat.errordoublenullableF2RXS/FeRASS1X-ray flux ratio F_2RXS_/F_eRASS1_phot.flux;arith.ratiodoublee_DistError in distancepcstat.errorintLumLuminosity (erg/s)1e-07Wphys.luminositydoublee_LumError in luminosity (erg/s)1e-07Wstat.errordoubleBP-RP? Gaia BP-RP colourmagphot.color;em.opt.B;em.opt.RfloatnullableGmagG magnitudemagphot.mag;em.optdoubleGMAGAbsolute G magnitudemagphys.magAbsdoubleGMAGc? Absolute_G corrected for extinctionmagphys.magAbsdoublenullableBP-RPc? BP-RP corrected for reddeningmagphot.color;em.opt.B;em.opt.RdoublenullableSimbadSpClassSIMBAD spectral classsrc.spTypecharPer? Orbital or spin Perioddtime.perioddoublenullableSimbadClassSimbad object type/classificationmeta.notecharSourceClassSource class from this workmeta.code.classcharT? Effective temperature from Gaia DR2Kphys.temperature.effectivefloatnullableRad? Radius from Gaia DR2solRadphys.size.radiusfloatnullableFinalSpClassFinal adopted spectral class using information from temperature and radiussrc.spTypecharGLON[0/360] Galactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latdouble