J/ApJ/916/32ivo://CDS.VizieR/J/ApJ/916/32doi:10.26093/cds/vizier.19160032CDSGetman K.V.Feigelson E.D.2023-08-16T15:05:30Z2023-01-23T08:59:05ZCDS support team

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

cds-question@unistra.frx-ray-sourcessurveyspre-main-sequence-starsstellar-flaresstellar-massesstellar-agesstar-forming-regionsinfrared-sourcesSolar-type stars exhibit their highest levels of magnetic activity during their early convective pre-main-sequence (PMS) phase of evolution. The most powerful PMS flares, superflares and megaflares, have peak X-ray luminosities of log(L_X_)=30.5-34.0erg/s and total energies log(E_X_)=34-38erg. Among >24000 X-ray-selected young (t<~5Myr) members of 40 nearby star-forming regions from our earlier Chandra MYStIX and SFiNCs surveys, we identify and analyze a well-defined sample of 1086 X-ray superflares and megaflares, the largest sample ever studied. Most are considerably more powerful than optical/X-ray superflares detected on main-sequence stars. This study presents energy estimates of these X-ray flares and the properties of their host stars. These events are produced by young stars of all masses over evolutionary stages ranging from protostars to diskless stars, with the occurrence rate positively correlated with stellar mass. Flare properties are indistinguishable for disk- bearing and diskless stars indicating star-disk magnetic fields are not involved. A slope of {alpha}~2 in the flare energy distributions dN/dE_X_{propto}E_X_^-{alpha}^ is consistent with that of optical/X-ray flaring from older stars and the Sun. Megaflares (log(E_X_)>36.2erg) from solar-mass stars have an occurrence rate of 1.7_-0.6_^+1.0^ flares/star/year and contribute at least 10%-20% to the total PMS X-ray energetics. These explosive events may have important astrophysical effects on protoplanetary disk photoevaporation, ionization of disk gas, production of spallogenic radionuclides in disk solids, and hydrodynamic escape of young planetary atmospheres. Our following paper details plasma and magnetic loop modeling of the >50 brightest X-ray megaflares.2021ApJ...916...32Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/916/32CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)I/259 : The Tycho-2 Catalogue (Hog+ 2000)II/341 : VPHAS+ DR2 survey (Drew+, 2016)II/348 : VISTA Variable in the Via Lactea Survey DR2 (Minniti+, 2017)I/345 : Gaia DR2 (Gaia Collaboration, 2018)V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)VI/156 : M-dwarf Lum-Temp-Radius relationships (Morrell+, 2019)J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)J/A+A/474/495 : X-ray flares from Cygnus OB2 stars (Albacete Colombo+, 2007)J/ApJS/169/353 : Chandra sources in M17 (Broos+, 2007)J/A+A/468/353 : XMM-Newton Extended Survey of Taurus (Guedel+, 2007)J/A+A/492/277 : Analysis of Collinder 69 stars with VOSA (Bayo+, 2008)J/ApJ/688/418 : X-ray flares in Orion young stars. I. (Getman+, 2008)J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)J/ApJS/209/27 : MYStIX: the Chandra X-ray sources (Kuhn+, 2013)J/ApJS/209/29 : MYStIX: Mid-IR observations and catalogs (Kuhn+, 2013)J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)J/ApJS/209/31 : The MYStIX IR-Excess Source catalog (MIRES) (Povich+, 2013)J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)J/ApJ/787/108 : Age estimates for massive SFR stellar pop. (Getman+, 2014)J/ApJS/213/1 : The MSFRs Omnibus X-ray Catalog (MOXC) (Townsley+, 2014)J/ApJ/814/35 : Flare events in M dwarf of M37 (Chang+, 2015)J/ApJ/812/131 : Structure of young stellar clusters. III. (Kuhn+, 2015)J/ApJ/802/60 : Structure of young stellar clusters. II. (Kuhn+, 2015)J/A+A/593/A7 : NH and AV Towards YSOs in the ONC (Hasenberger+, 2016)J/ApJS/229/28 : SFiNCs: X-ray, IR and membership catalogs (Getman+, 2017)J/ApJ/869/L41 : DSHARP I. Sample, ALMA obs. log & overview (Andrews+, 2018)J/A+A/618/A93 : Gaia DR2 open clusters in the MW (Cantat-Gaudin+, 2018)J/A+A/620/A55 : Magnetic flaring from PMS stars spectra (Flaccomio+, 2018)J/MNRAS/477/298 : Young star clusters in nearby MoCs (Getman+, 2018)J/MNRAS/477/5191 : Ggalactic young stellar cluster lifetimes (Richert+, 2018)J/A+A/609/A10 : NGC2264 structure and star formation history (Venuti+, 2018)J/ApJ/869/72 : IN-SYNC. VIII. YSOs in NGC1333, IC348 & Orion A (Yao+, 2018)J/AJ/158/235 : X-ray sources in IRAS 09002-4732 region (Getman+, 2019)J/ApJ/878/111 : Members in Serpens MoC with Gaia DR2 (Herczeg+, 2019)J/ApJ/881/9 : EvryFlare. I. Cool stars's flares (Howard+, 2019)J/A+A/622/A133 : M45, M44 and M67 flare stars (Ilin+, 2019)J/ApJ/870/32 : Kinematics in young star clusters & assoc. (Kuhn+, 2019)J/A+A/637/A22 : M dwarfs rotation-activity relations & flares (Raetz+, 2020)J/A+A/648/A121 : X-ray activity and accretion in the ONC (Flaischlen+, 2021)J/A+A/645/A42 : Flares in 5 open clusters (Ilin+, 2021)J/ApJ/906/72 : 2344 superflares on 266 solar-type stars (Okamoto+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/916/32https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/916/32http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/916/32https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/916/32https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/916/32http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/916/32GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/916/32/table1 (MYStIX and SFiNCs regions)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/916/32/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/916/32/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/916/32/table1?GETtext/xml+votable180.050000true0.667.40.005555555555555556Cone search capability for table J/ApJ/916/32/table2 (MYStIX and SFiNCs F+R+D flare host star properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/916/32/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/916/32/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/916/32/table2?GETtext/xml+votable180.050000true0.22272567.437501110.005555555555555556Cone search capability for table J/ApJ/916/32/table4 (Super-flares from protostellar candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/916/32/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/916/32/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/916/32/table4?GETtext/xml+votable180.050000true344.0815988962.039843060.0055555555555555565/10615 6/862 1231 1285 1287 1298 1539 3307 3649 3755 3759 13050 14029 14621 14682 14704 15662-15663 15681 15683-15684 16197 21438-21439 21456 21458 22243 22249 22805 22855 22873 22876 23637 23639 28890-28891 28913 29116 29118 29463 29506 30341 30343 30366 37872 37884 37923 37926 38016 39907 42441 42456-42458https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/916/32?format=asciiX-rayInfrareddefaultJ/ApJ/916/32/table1MYStIX and SFiNCs regionsSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionStar forming region shortname used in Tables 2-4meta.idcharprimarySFRStar forming regionmeta.id;meta.maincharRAJ2000SFR right ascension, decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000SFR declination, decimal degrees (J2000)degpos.eq.dec;meta.mainDist[296/3790] Distance from the Sunpcpos.distance;pos.heliocentricintNXobs[39/6751] Number of observed X-ray emitting young stars (2)meta.numberintNsNumber of host star in this region (link to Table 2)meta.numberintnullableNtot[39/37899] Total inferred stellar population (3)meta.numberintr_Dist[1/7] Reference for Dist (1)meta.ref;pos.frameintJ/ApJ/916/32/table2MYStIX and SFiNCs F+R+D flare host star propertiesSimbadNameSimbad column added by the CDSmeta.idcharnullableRegionStar forming region (See Table 1)meta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar name (HHMMSS.ss+DDMMSS.s; J2000)meta.id;meta.maincharRAJ2000Right Ascension, decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination, decimal degrees (J2000)degpos.eq.dec;meta.mainME[0.9/5.8] X-ray median energy (1)keVphys.energy;stat.median;em.X-rayfloatlogLx[30/32.7] Log of intrinsic X-ray luminosity, in erg/s units (1)log(1e-07W)phys.luminosity;em.X-rayfloatAv[-12/53.3]? Reddening, V-band (2)magphys.absorptionfloatnullableAge[0.4/5]? Age (2)Myrtime.agefloatnullablelogTeff[3.4/4.8]? log of surface effective temperature (2)log(K)phys.temperature.effectivefloatnullablelogLbol[-1.4/7]? log of bolometric luminosity (2)log(solLum)phys.luminosityfloatnullableMstar[0.1/320.2]? Mass (2)solMassphys.massfloatnullableRstar[0.9/31.4]? Radius (2)solRadphys.size.radiusfloatnullablealpha[-4.3/4.4]? IRAC SED slope (2)spect.indexfloatnullableFlagFlag (2)meta.code.errorcharMYStIXDisplay data from Kuhn+ 2013, J/ApJS/209/27 and Broos+ 2013, J/ApJS/209/32meta.ref.urlintnullableSFiNCSDisplay data from Getman+, 2017, J/ApJS/229/28meta.ref.urlintnullableNfNumber of flares for this star (link to Table 3)meta.numberintnullableJ/ApJ/916/32/table3MYStIX and SFiNCs F+R+D super-flaresObsID[1/9] Relative sequence number of the X-ray Chandra observation (G1) (1)meta.id;obsintExp[11.8/154] Chandra ObsID Exposurekstime.expofloatClassFlare class (2)meta.codecharNphot[15/19891] Flare X-ray countsctphot.count;em.X-rayintME[0.9/5.7] Flare median photon energykeVphys.energy;stat.median;em.X-rayfloatRegionStar forming region (See Table 1)meta.idcharl_DurLimit flag on Durmeta.code.errorcharDur[1.9/153.9] Flare durationkstime.durationfloatl_logLxpkLimit flag on logLxpkmeta.code.errorcharlogLxpk[30.6/33.8] log of peak X-ray luminosity, in erg/s unitslog(1e-07W)phys.luminosity;em.X-rayfloatl_logExLimit flag on logExmeta.code.errorcharlogEx[34.1/37.6] log of flare energy, in erg unitslog(1e-07J)em.energyfloatSfDisplay this super-flare data (link to Table 4)meta.ref.urlintnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameFlare host star name (HHMMSS.ss+DDMMSS.s; J2000) (G1)meta.id;meta.maincharJ/ApJ/916/32/table4Super-flares from protostellar candidatesClassFlare Class (1)meta.codecharRAJ2000[52.2/344.1] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-47.6/75.2] Declination (J2000)degpos.eq.dec;meta.mainalpha[0.3/2.1]? IRAC SED slope, {alpha}spect.indexfloatnullableNphot[21/296] Flare X-ray countsctphot.count;em.X-rayintME[5/5.7] Flare median photon energykeVphys.energy;stat.median;em.X-rayfloatl_logLxpkLimit flag on logLxpkmeta.code.errorcharlogLxpk[31.3/33.8] log of peak X-ray luminosity, in erg/s unitslog(1e-07W)phys.luminosity;em.X-rayfloatl_logExLimit flag on logExmeta.code.errorcharlogEx[34.9/37.6] log of flare energy, in erg unitslog(1e-07J)em.energyfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionStar forming region (See Table 1)meta.idcharNameX-ray host star name (G1)meta.id;meta.maincharObsID[1/6] X-ray Chandra observation as in Table 3 (G1)meta.id;obsint