J/A+A/702/A218ivo://CDS.VizieR/J/A+A/702/A218doi:10.26093/cds/vizier/bc-ny/lcbiCDSFritzewski D.J.Barnes S.A.Ok S.Lamer G.Schwope A.2026-08-03T06:58:06Z2025-10-24T10:30:32ZCDS support team

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

cds-question@unistra.fropen-star-clusterslate-type-starsx-ray-sourcesspectroscopyThe coronal soft X-ray emission of cool stars, especially in combination with their measured rotation periods, provides insight into their levels of magnetic activity and related transitions. We study the X-ray properties of low-mass (FGKM-type) members of the open cluster NGC 2516 to explicate their detailed dependencies on mass and rotation. We analyse the pointed SRG/eROSITA satellite observations of NGC 2516 obtained during the calibration and performance verification phase of the mission. We find 1561 X-ray sources within the field of view. Of these we relate 1007 to optical stellar counterparts, including 655 members of NGC 2516, 433 of which have measured rotation periods. We combine these detections with auxiliary optical data to enable interpretation. Furthermore, we extract X-ray spectra for all sources and fit two-component APEC models to them. To aid analysis, we group stars with similar mass and rotational properties, allowing us to investigate the influence of rotation on various X-ray properties. The colour-activity diagram of NGC 2516 shows a general increase of the fractional X-ray luminosity with spectral type change from F through G and K to M-type. However, the behaviour of K-type stars, representing those best sampling the fast- to slow rotational transition, is more complex, with both increased and decreased X-ray emission relative to G-type stars for fast and slow rotators respectively. The rotation-activity diagram is analogous, with an identifiable desaturated group of X-ray emitters that corresponds to stars in the rotational gap between the fast and slow rotator sequences. We prefer describing the normalized X-ray emission for all cluster stars as declining logarithmically with Rossby number over those using broken power laws. Coronal temperatures appear to be largely independent of mass or rotation. The coronal abundances are significantly sub-solar for most stars, as in prior work, but near-solar for both the least-active stars in our sample and a number of the very active stars. The wealth of X-ray detections and rotation periods for stars in NGC 2516 enables a detailed view of the connection between rotation and X-ray activity in a homogeneous and coeval cluster sample of young stars.2025A&A...702A.218Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/702/A218CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/A+A/450/993 : XMM survey of NGC 2516 (Pillitteri+, 2006)J/ApJ/588/1009 : Chandra X-ray observations of NGC 2516 (Damiani+, 2003)J/A+A/641/A51 : NGC 2516 membership list (Fritzewski+, 2020)J/AJ/162/197 : Photometry, rotation and Li in open cluster NCG 2516https://erosita.mpe.mpg.de/edr/eROSITAObservations : eROSITA-DE,https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/702/A218https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/702/A218http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/702/A218https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/702/A218https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/702/A218http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/702/A218GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/702/A218/table2 (All eROSITA detections in the field of view)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A218/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A218/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A218/table2?GETtext/xml+votable180.050000true120.07412-61.163720.005555555555555556Cone search capability for table J/A+A/702/A218/table3 (*APEC fits of stellar sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A218/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A218/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A218/table3?GETtext/xml+votable180.050000true119.88402-60.812490.005555555555555556Cone search capability for table J/A+A/702/A218/table4 (Optical counterparts as matched with Gaia DR3)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A218/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A218/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A218/table4?GETtext/xml+votable180.050000true120.07412-61.163720.005555555555555556Cone search capability for table J/A+A/702/A218/tableb1 (Power-law spectra of non-stellar sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A218/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A218/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A218/tableb1?GETtext/xml+votable180.050000true119.85966-60.975930.0055555555555555566/37586-37587 37592-375941.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/702/A218?format=asciiX-raydefaultJ/A+A/702/A218/table2All eROSITA detections in the field of viewrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintmoreindicates more data in tables 3 and/or 4meta.ref.urlcharSRCID[1/1634] eROSITA source IDmeta.id;meta.mainintprimaryRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainePos? Positional uncertaintydegstat.error;posdoublenullableCrateCount rates**-1phot.count;em.X-raydoublee_Crate? Uncertainty on count rates**-1stat.error;phot.countdoublenullableFluxX-ray flux calculated with ECF for NGC 25161e-18W.m**-2phot.flux;em.X-raydoublee_Flux? Uncertainty on X-ray flux1e-18W.m**-2stat.error;phot.fluxdoublenullableJ/A+A/702/A218/table3*APEC fits of stellar sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSRCID[2/1629] eROSITA source ID, as in table2meta.id;meta.mainintRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainePos? Positional uncertaintydegstat.error;posdoublenullableAPEC1kT? Temperature of first APEC componentkeVphys.temperaturefloatnullablebAPEC1kT? Lower bound of first APEC componentkeVstat.errorfloatnullableBAPEC1kT? Upper bound of first APEC componentkeVstat.errorfloatnullableAPEC2kT? Temperature of second APEC componentkeVphys.temperaturefloatnullablebAPEC2kT? Lower bound of second APEC componentkeVstat.errorfloatnullableBAPEC2kT? Upper bound of second APEC componentkeVstat.errorfloatnullablemeankT? Weighted mean temperature of both APEC componentskeVphys.temperaturefloatnullablee_meankTUncertainty on mean temperaturekeVstat.errorfloatAbundAbundance of APEC fitstat.fit.param;meta.modelledfloate_AbundUncertainty on abundancestat.errorfloatProbNull hypothesis probabilitystat.probabilitydoubleJ/A+A/702/A218/table4Optical counterparts as matched with Gaia DR3recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSRCID[1/1631]? eROSITA source ID, as in table2 (1)meta.id;meta.mainintnullableRAJ2000? Right ascension (J2000.0) from eROSITA (1)degpos.eq.ra;meta.mainnullableDEJ2000? Declination (J2000.0) from eROSIAT (1)degpos.eq.dec;meta.mainnullableGaiaDR3Gaia DR3 source_idmeta.idRAGdegRight ascension from Gaia DR3 (ICRS) at Ep=2016.0 (Cat. I/355)degpos.eq.raDEGdegDeclination from Gaia DR3 (ICRS) at Ep=2016.0 (Cat. I/355)degpos.eq.decTeff? Effective temperature derived from photometryKphys.temperature.effectiveintnullableGmagG magnitude from Gaia DR3 (Cat. I/355)magphot.mag;em.optfloat(G-RP)0(G-RP)_0 colour from Gaia DR3 (Cat. I/355)magphot.color;em.opt;em.optfloatlogLX/LbolFractional X-ray luminosityphys.luminosity;arith.ratiofloate_logLX/Lbol? Uncertainty on fractional X-ray luminositystat.errorfloatnullableMember[0/1] Indicates membership statusmeta.noteintPer? Rotation period from the literaturedtime.periodfloatnullableRo? Solar-scaled Rossby numberSunstat.paramfloatnullableMultiple[1]? Indicates whether two sources are within 7 arcsecmeta.codefloatnullableJ/A+A/702/A218/tableb1Power-law spectra of non-stellar sourcesNHHydrogen column density1e+22cm**-2phys.columnDensityfloatPhoIndexPower-law index of spectral fitspect.indexfloatb_PhoIndex? Lower bound of power-law indexmeta.code;spect.index;stat.minfloatnullableB_PhoIndex? Upper bound of power-law indexmeta.code;spect.index;stat.maxfloatnullablePhoIndexnormNormalization of power-law indexspect.indexdoubleProbNull hypothesis probabilitystat.probabilitydoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSRCID[4/1634] eROSITA source IDmeta.id;meta.mainintRAJ2000? Right ascension (J2000.0)degpos.eq.ra;meta.mainnullableDEJ2000? Declination (J2000.0)degpos.eq.dec;meta.mainnullable