J/A+A/661/A29ivo://CDS.VizieR/J/A+A/661/A29doi:10.26093/cds/vizier.36610029CDSMagaudda E.Stelzer B.Raetz St.Klutsch A.Salvato M.Wolf J.2024-12-23T20:00:50Z2022-05-18T13:49:10ZCDS support team

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

cds-question@unistra.frm-starsx-ray-sourcesWe present the first results with the ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Russian Spektrum-Roentgen-Gamma mission (SRG), and we combine the new X-ray data with observations with the Transiting Exoplanet Survey Satellite (TESS). We use the superblink proper motion catalog of nearby M dwarfs as input sample to search for eROSITA and TESS data. We extracted Gaia-DR2 data for the full M dwarf catalog that comprises ~9000 stars, and we calculated the stellar parameters from empirical relations with optical/IR colors. Then we cross-matched this catalog with the eROSITA Final Equatorial Depth Survey (eFEDS) and the first eROSITA all-sky survey (eRASS1). After a meticulous source identification in which we associate the closest Gaia source to the eROSITA X-ray detections, our sample of M dwarfs is defined by 687 stars with SpT = K5..M7 (673 from eRASS1 and 14 from eFEDS). While for eRASS1 we used the data from the source catalog provided by the eROSITA_DE consortium, for the much smaller eFEDS sample we performed the data extraction and we analyzed the X-ray spectra and light curves. This unprecedented data base for X-ray emitting M dwarfs allowed us to put a quantitative constraint on the mass dependence of the X-ray luminosity, and to determine the change in the activity level with respect to pre-main-sequence stars. TESS observations are available for 489 of 687 X-ray detected M dwarfs, and applying standard period search methods we could determine the rotation period for 180 X-ray detected M dwarfs, about one forth of the X-ray sample. With the joint eROSITA and TESS sample, and combining it with our compilation of historical X-ray and rotation data for M dwarfs, we examine the mass dependence of the "saturated" regime of the rotation-activity relation. A first comparison of eROSITA hardness ratios and spectra shows that 65% of the X-ray detected M dwarfs have coronal temperatures of ~0.5keV. We performed a statistical investigation of the long-term X-ray variability of M dwarfs comparing the eROSITA measurements to those obtained ~30 years earlier during the ROSAT all-sky survey (RASS). Evidence for X-ray flares are found in various parts of our analysis: directly from an inspection of the eFEDS light curves, in the relation between RASS and eRASS1 X-ray luminosities, and in a subset of stars that displays X-ray emission hotter than the bulk of the sample according to the hardness ratios. Finally, we point out the need to obtain X-ray spectroscopy for more M dwarfs to study the coronal temperature-luminosity relation that is not well constrained by our eFEDS results.2022A&A...661A..29Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/661/A29CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)I/347 : Distances to 1.33 billion stars in Gaia DR2J/AJ/142/138 : All-sky catalog of bright M dwarfs (Lepine+, 2011)J/A+A/588/A103 : Second ROSAT all-sky survey (2RXS) source catalogJ/A+A/661/A1 : The eFEDS X-ray catalogs (V7.4) (Brunner+, 2022)J/A+A/661/A2 : Galaxy clusters and groups in eFEDS (Liu+, 2022)J/A+A/661/A3 : eFEDS counterparts to point-like sources (Salvato+, 2022)J/A+A/661/A4 : eFEDS optical cluster and group catalog (Klein+, 2022)J/A+A/661/A5 : The eFEDS AGN catalog (Liu+, 2022)J/A+A/661/A7 : X-ray properties of eFEDS clusters and groups (Bahar+, 2022)J/A+A/661/A8 : eFEDS catalogue of variable X-ray sources (Boller+, 2022)J/A+A/661/A10 : eFEDS galaxy clusters and groups in disguise (Bulbul+, 2022)J/A+A/661/A23 : Exoplanet X-ray irradiation & evaporation rates (Foster+, 2022)J/A+A/661/A24 : Corona-chromosphere connection (Fuhrmeister+, 2022)J/A+A/661/A34 : eta Cha cluster eROSITA X-ray scan (Robrade+, 2022)J/A+A/661/A35 : eROSITA study of 47 Tuc globular cluster (Saeedi+, 2022)J/A+A/661/A38 : SRG/ART-XC 1st year all-sky X-ray survey (Pavlinsky+, 2022)J/A+A/661/A40 : eRASS1 X-ray sources Sco-Cen members (Schmitt+, 2022)J/A+A/661/A44 : A first eROSITA view of ultracool dwarfs (Stelzer+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/661/A29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/661/A29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/661/A29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/661/A29https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/661/A29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/661/A29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/661/A29/tables (Stellar parameters and distances (table 2), X-ray parameters (table 3) and X-ray activity and rotation (table 5) (updated version, 23/12/2024))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/661/A29/tables?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/661/A29/tables?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/661/A29/tables?GETtext/xml+votable180.050000true133.781821.540726940.0055555555555555566/4098-4099 4102-4104 4155 4186 4282 4297 4299 4366 4391 4401 4444 4462 4468 4629 4651 4696 4733 4764 4801 4808 4836 4895 4932 4974 4976 4982 5000 5009 5145 5207 5224 5320 5337 5351 5371 5387 5420 5514 5651 5765 6146 6169 6245 6294-6295 6305 6325 6340 6346 6374 6379 6384 6672 6674 6676 8738-8739 16391 16426 16454 16462 20505 20599 20612 20632 20683 20690 20695 20743 20839 20896 20957 20989 21047 21136 21146 21149 21165 21242 21254 21338 21396 21433 21472 21591 21594 21676 21681 21687 21737 21748 21785 21975 21979 22037 22040 22060 22148 22170 22180 22185 22215 22237 22250 22279 22292 22343 22367 22390 22461 22491 22510 22535 22571 22596 22626 22645 22647 22683 22731 22738 22778 22811 22830 22856 22873 22882 22904 22942 22952 22954 22958 22967 22974 23014 23018 23042 23065 23067 23092 23094 23137 23152 23165 23265 23298 23329 23363 23370 23383 23391 23400 23402-23403 23408 23443-23444 23455 23472 23475 23500-23501 23505 23507 23510 23515 23523 23527 23564 23586 23596 23719 23731 23741 23752 23787 23824 23857 23867 23887-23888 23897 23985 24053 24103 24114 24173-24174 24184 24192 24197 24209 24217 24223 24330 24336 24426 24615 24713 24779 24792 24843 24905 24915 24949 24961 24976 24995 25021 25023 25084 25091 25162 25217 25238 25265 25278 25356 25374 25431 25488 25508 25512 25528 25546 25594 25616 25637-25638 25653 25745 25815 25820 25862 25877 25889 25902 25923 25935 25979 25989 26002 26054-26055 26129 26161 26192 26196-26197 26216 26250 26276 26279 26288 26327 26334 26388 26394 26401 26467 26487 26492 26525 26557 26588 26614-26615 26699 26706 26747 26757 26772 26795 26798 26972 27009 27056 27115 27141 27187 27201 27204 27250 27282 27290 27301 27305-27306 27314 27317 27320 27326 27392 27397 27419 27442 27456 27510 27611 27642 27671 27692 27706 27714 27730 27762 27792 27799 27817 27822 27856 27886 27895 27912 27951-27952 28060 28078 28087 28115 28134 28144 28180 28184 28195 28279 28283 28336 28341 28343 28346 28404 28426 28491 28574 29344 29346 29352 30883 32782 32910 32953 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47826https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/661/A29?format=asciiX-raydefaultJ/A+A/661/A29/tablesStellar parameters and distances (table 2), X-ray parameters (table 3) and X-ray activity and rotation (table 5) (updated version, 23/12/2024)KsMAGAbsolute 2MASS Ks-magnitude (5)magphys.magAbsfloate_KsMAGUncertainty on the absolute 2MASS Ks-mag (5)magstat.errorfloatMassStellar mass (5)solMassphys.massfloate_MassError on stellar mass (5)solMassstat.error;phys.massfloatbinaryFlag for binary systems (6)meta.codeintMannIndValidation flag of the stellar parameters according to Mann (7)meta.codeinteROSITAThe eROSITA Survey where the star has been detectedmeta.idcharRAJ2000Corrected X-ray right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Corrected X-ray declination (J2000)degpos.eq.dec;meta.mainSepXOptSeparation between the optical and the X-ray positionsarcsecpos.angDistancefloatCRate0Count Rate in 0.2-5.0keV0.001count.s**-1phot.count;em.X-raydoubleDetML0Detection Likelihood in 0.2-5.0keVstat.likelihooddoubleHR1Hardness ratio between the energy bands: 0.6-2.3keV and 0.2-0.6keVphot.flux;em.X-ray.soft;arith.ratiofloatHR2? Hardness ratio between the energy bands: 2.3-5.0keV and 0.6-2.3keVphot.flux;em.X-ray.medium;arith.ratiofloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequential numbermeta.recordintLG11NameSource Name, PM IHHMMSS+DDMMAA (1)meta.id;meta.maincharGaiaDR2Gaia-DR2 ID (2)meta.idSpTypeSpectral type using Gbp-Grp color (3)src.spTypecharlogLxeReROSITA X-ray luminosity in log scalelog(1e-07W)phys.luminosity;em.X-rayfloatlogLxR? ROSAT X-ray luminosity in log scale (8)log(1e-07W)phys.luminosity;em.X-rayfloatnullablelogLx/LbolFractional X-ray luminosity in log scalephys.luminosity;arith.ratiofloatTIC? TIC Namemeta.idnullableProt? Rotation period extracted from TESS LCdtime.periodfloatnullablef_Prot? Rotation period flag (9)meta.codeintnullableRo? Rossby number (10)stat.paramdoublenullableSNameSimbad namemeta.idcharDistGaia distances (4)pcpos.distancefloate_DistUncertainty on Gaia distances (4)pcstat.errorfloat