2XMM Flares Detected from Tycho-2 Stars

2XMM Flares Detected from Tycho-2 Stars XMMT2FLARE ivo://nasa.heasarc/xmmt2flare NASA/GSFC HEASARC Pye et al. 2026-07-17 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the results from a uniform, large-scale survey of X-ray flare emission, based on the XMM-Newton Serendipitous Source Catalog (2XMM) and its associated data products. This survey comprises both XMM-targeted active stars and those observed serendipitously in the half-degree diameter field-of-view of an observation. The 2XMM Catalog and the associated time-series ('light-curve') data products have been used as the basis for the survey of X-ray flares from cool stars in the Hipparcos Tycho-2 catalog. In addition, the authors have generated and analyzed spectrally-resolved (i.e. hardness-ratio) X-ray light-curves. Where available, they have compared XMM OM UV/optical data with the X-ray light-curves. Their sample contains ~130 flares with well-observed profiles; they originate from ~70 stars. The flares range in duration from ~103 to ~104 s, have peak X-ray fluxes from ~10-13 to ~10-11 erg cm-2 s-1, peak X-ray luminosities from ~1029 to ~1032 erg s-1, and X-ray energy output from ~1032 to ~1035 erg. Most of the ~30 serendipitously-observed (target_flag = 'N') stars have little previously reported information. The hardness-ratio plots clearly illustrate the spectral (and hence inferred temperature) variations characteristic of many flares, and provide an easily accessible overview of the data. In the reference paper, the authors present flare frequency distributions from both target and serendipitous observations. The latter provide an unbiased (with respect to stellar activity) study of flare energetics; in addition, they allow the authors to predict the numbers of stellar flares that may be detected in future X-ray wide-field surveys. The serendipitous sample demonstrates the need for care when calculating flaring rates, especially when normalizing the number of flares to a total exposure time, where it is important to consider both the stars seen to flare and those from which variability was not detected (i.e., measured as non-variable), since in the present survey, the latter outnumber the former by more than a factor of ten. This table was created by the HEASARC in September 2015 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/581/A28">CDS Catalog J/A+A/581/A28</a> files tablec1.dat and tablec2.dat. This is a service provided by NASA HEASARC . 2013ApJ...770...98V https://heasarc.gsfc.nasa.gov/W3Browse/all/xmmt2flare.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=xmmt2flare& GET text/xml 180 99999 true 166.5643825 -77.36581944 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=xmmt2flare GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_xmmt2flare&Action=More+Options&Action=Parameter+Search&ConeAdd=1 XMM-NEWTON 0.0166666666666667 X-ray public xmmt2flare 2XMM Flares Detected from Tycho-2 Stars twoxmm_detid 2XMM Detection Identifier meta.id int nullable name Star Designation (from SIMBAD+) meta.id;meta.main char nullable ra Right Ascension (from Tycho-2) degree pos.eq.ra;meta.main double nullable dec Declination (from Tycho-2) degree pos.eq.dec;meta.main double nullable vmag V-Band Apparent Magnitude of Star (Tycho-2 Derived) phot.mag;em.opt.V double nullable spect_type Star Spectral Type (from SIMBAD+) src.spType char nullable flare_flag Flag [YN] Indicates Flare (This Work) meta.code char nullable quies_fx Quiescent Level, Mean X-Ray Flux in Total Band, 0.2-12keV (This Work) erg/s/cm^2 phot.flux;em.X-ray double nullable peak_fx Flare Peak X-Ray Flux, Above Quiescent in Total Band, 0.2-12keV (This Work) erg/s/cm^2 phot.flux;em.X-ray double nullable event_number Event Identifier (This Work) meta.number short nullable event_energy X-Ray Emitted Energy (This Work) erg phys.energy;em.X-ray double nullable event_duration Flare Duration, Time Between 1/e Points (This Work) s time.duration int nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable alt_name Alternative Designation (from SIMBAD+) meta.id char nullable var_instrument Variability Instrument Identifier (from 2XMM) (VAR_INST_ID) (G2) char nullable number_events Number of Flares or Other Events Identified in the Light-Curve (This Work) meta.number short nullable twoxmm_name IAU Source Designation Assigned to Source Identifier (from 2XMM) meta.id char nullable class Browse Object Classification src.class short nullable twoxmm_srcid 2XMM Source Identifier meta.id int nullable ref_distance Source of Distance Value meta.ref;pos.distance char nullable event_snr Signal-to-Noise Ratio of Event (This Work) stat.snr;em.X-ray double nullable m1_filter M1 Filter (from 2XMM) instr;instr.filter char nullable off_axis Off-Axis Angle (2XMM Derived) arcmin instr.offset double nullable target_flag Flag [YN] Indicates Target Flag (from 2XMM) meta.code;src char nullable peak_lx Flare Peak X-Ray Luminosity, Above Quiescent in Total Band 0.2-12keV (This Work) erg/s phys.luminosity;em.X-ray double nullable peak_time_relative Time of Flare Peak Relative to Observation Start (This Work) s time.duration int nullable lii Galactic Longitude (Derived from Tycho-2) degree pos.galactic.lon double nullable full_profile_flag Flag [YN] Indicates Event Profile (This Work) meta.code char nullable fall_time Flare Fall Time, Peak to 1/e (This Work) s time.duration int nullable pn_filter PN Filter (from 2XMM) instr;instr.filter char nullable twoxmm_sum_flag Data Quality Flag (2XMM Derived) meta.code.qual short nullable bii Galactic Latitude (Derived from Tycho-2) degree pos.galactic.lat double nullable peak_over_quies_fx Flare Peak-to-Quiescent Ratio, X-Ray Flux or Luminosity (This Work) phot.flux;em.X-ray;arith.ratio double nullable ontime Observation On-Time (2XMM Derived) s time.duration;obs.exposure double nullable twoxmm_srcid_2 Additional 2XMM Source Identifier meta.id int nullable log_2xmm_fx_over_fv Logarithm of Ratio of Total-Band [0.2-12keV] 2XMM Flux to Visual Tycho-2 Flux phot.flux;arith.ratio double nullable tycho2_name Star Identifier in Tycho-2 Catalog meta.id.cross char nullable variable_flag Flag [YN] Indicates Variable, Cool-Star (This Work) meta.code;src char nullable rise_time Flare Rise Time, 1/e to Peak (This Work) s time.duration int nullable ref_star Selected Reference(s) to Star (This Work) meta.ref char nullable ref_xmm_result Reference(s) to XMM-Newton Results (This Work) meta.ref char nullable "time" Date/Time of Observation Start (from 2XMM) mjd time.start;obs double nullable bv_color B-V Color of Star, Uncorrected for Reddening (Tycho-2 Derived) phot.color;em.opt.B;em.opt.V double nullable obsid XMM-Newton Observation Identifier (from 2XMM) meta.id;obs char nullable m2_filter M2 Filter (from 2XMM) instr;instr.filter char nullable log_2xmm_lx Logarithm of Total-Band [0.2-12keV] X-Ray Luminosity log(erg/s) phys.luminosity;em.X-ray double nullable notes Notes on Properties of Star, etc. (This Work) meta.note char nullable broad_type Star Type, Category, or Characteristics (from SIMBAD) src.class char nullable event_type Event Type (This Work) src.class char nullable twoxmm_summary_url URL of 2XMM Summary-Results Web Page at LEDAS (2XMM Derived) meta.ref.url char nullable "distance" Distance to Star from Earth pc pos.distance double nullable quies_lx Quiescent Level, Mean X-Ray Luminosity in Total Band, 0.2-12keV (This Work) erg/s phys.luminosity;em.X-ray double nullable peak_time Time of Flare Peak (This Work) mjd time.epoch double nullable end_time Date/Time of Observation End (from 2XMM) mjd time.end;obs double nullable