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XMMT2FLARE - 2XMM Flares Detected from Tycho-2 Stars

HEASARC
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Overview

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.

Catalog Bibcode

2013ApJ...770...98V

References

A survey of stellar X-ray flares from the XMM-Newton serendipitous source
catalogue: Hipparcos-Tycho cool stars.
    Pye J.P., Rosen S., Fyfe D., Schroeder A.C.
    <Astron. Astrophys. 581, A28 (2015)>
    =2015A&A...581A..28P        (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in September 2015 based on the CDS Catalog J/A+A/581/A28 files tablec1.dat and tablec2.dat.

Parameters

TwoXMM_Detid
A consecutive number which identifies each entry (detection) in the 2XMM catalog.

Name
A common designation for the star, taken from the CDS SIMBAD database and other sources.

Alt_Name
An alternative designation for the star, taken from the CDS SIMBAD database and other sources.

Tycho2_Name
The stellar identifier taken from the Tycho-2 Catalog.

RA
The Right Ascension of the star in the selected equinox, taken (by the HEASARC) from the Tycho-2 Catalog. This should be regarded as merely indicative since stellar proper motion has not been taken into account.

Dec
The Declination of the star in the selected equinox, taken (by the HEASARC) from the Tycho-2 Catalog. This should be regarded as merely indicative since stellar proper motion has not been taken into account

LII
The Galactic Longitude of the star (derived from the Tycho-2 position).

BII
The Galactic Latitude of the star (derived from the Tycho-2 position).

Vmag
The stellar V-band apparent magnitude, taken from the Tycho-2 Catalog.

BV_Color
The stellar B-V color, uncorrected for reddening, taken from the Tycho-2 Catalog.

Spect_Type
The stellar spectral type, taken from the CDS SIMBAD database and other sources.

Broad_Type
The stellar type, category, or other characteristics, taken from the CDS SIMBAD database, e.g., Algol, BY Dra, del Sct (delta Scuti variable), double star system, EB (eclipsing binary), FK Com, flare star, Orion-type variable, PMS (pre-main-sequence star), RS CVn-type, SB (spectroscopic binary), SB1 (single-lined SB), or W UMa.

Distance
The distance of the star from the earth, in parsecs.

Ref_Distance
A code for the reference source for the cited distance value, as follows:

    HIP = Hipparcos (van Leeuwen 2007, CDS Cat. I/311)
    TYC = Tycho (2000,CDS Cat. I/259) (ph. par. from V)
    N2K = Ammons et al. (2006, ApJ, 638, 1004, CDS Cat. V/136)
    GCT = van Altena et al. (1995, CDS Cat. I/238)
    B04 = Budding et al. (2004, CDS Cat. J/A+A/417/263)
    F03 = Favata et al. (2003, A&A, 403, 187)
    F07 = Franciosini et al. (2007, A&A, 468, 485)
    F95 = Favata et al. (1995, A&A, 298, 482)
    G07 = Guedel et al. (2007, CDS Cat. J/A+A/468/353)
    M09 = Morales et al. (2009, CDS Cat. J/ApJ/707/671)
    M81 = Marraco et al. (1981, AJ, 86, 62)
    R95 = Reid et al. (1995, AJ, 110, 1838, CDS Cat. III/198)
    R99 = Robichon et al. (1999, CDS Cat. J/A+A/345/471)
    S04 = Stelzer et al. (2004, CDS Cat. J/A+A/423/1029)
    T02 = Tsujimoto et al. (2002, CDS Cat. J/ApJ/566/974)
    Z04 = Zuckerman et al. (2004, CDS Cat. J/other/ARA+A/42.685)
  

Target_Flag
This flag parameter indicates whether ('Y') or not ('N') the star was the target of the XMM-Newton observation (taken from the 2XMM Catalog).

Variable_Flag
This flag parameter is set to 'Y' if the star was in the authors' Cool, Variable Sample (CVS) or to 'N' if it is in their Cool, Low-Variable Sample (CLVS). See Section 3 of the reference paper for more details on these two samples.

TwoXMM_SrcID
The 2XMM source identifier. This is a unique number assigned to a group of 2XMM catalogue entries (DETIDs) which are assumed to be the same source.

TwoXMM_SrcID_2
An additional 2XMM source identifier. This indicates if a 2XMM source identifier should be matched to another one, and relates to high-proper-motion stars.

TwoXMM_Name
The IAU-style 2XMM source designation assigned to the specified 2XMM source identifier.

Log_2XMM_Fx_Over_Fv
The logarithm of the ratio of the total-band [0.2-12 keV] 2XMM X-ray flux to the visual-band Tycho-2 flux for the star.

Log_2XMM_Lx
The logarithm of the total-band [0.2-12 keV] X-ray luminosity of the star, in erg s-1, derived from the 2XMM X-ray flux and the assumed distance.

ObsID
The XMM-Newton observation identifier (ObsID), taken from 2XMM.

Time
The date and time of the start of the specified observation taken from 2XMM.

End_Time
The date and time of the end of the specified observation taken from 2XMM.

Ontime
The "ontime" for the MOS1 camera M1_ONTIME, for the specified observation, if available, else the "ontime" for the MOS2 camera (M2_ONTIME), else the "ontime" for the PN camera (PN_ONTIME), in seconds. Here **_ONTIME is the total good exposure time (after GTI filtering) for the detection in the corresponding camera. These values are taken from 2XMM.

PN_Filter
The PN filter used for the specified observation, taken from 2XMM.

M1_Filter
The MOS1 filter used for the specified observation, taken from 2XMM.

M2_Filter
The MOS2 filter used for the specified observation, taken from 2XMM.

Off_Axis
The minimum of the off-axis angle of the source from the nominal pointing direction for the 3 XMM-Newton cameras, i.e, min[PN_OFFAX, M1_OFFAX, M2_OFFAX], in arcminutes, taken from 2XMM.

Var_Instrument
The instrument (PN, M1, M2) corresponding to the exposure with the lowest variability chi-squared probability, taken from 2XMM.

TwoXMM_Sum_Flag
The summary "quality" flag for the detection, based on the 2XMM SUM_FLAG parameter, but re-evaluated for present work, as follows:

    0 = good (2XMM SUM_FLAG)
    1 = source parameters may be affected (2XMM SUM_FLAG)
    3 = located in a area where spurious detection may occur (2XMM SUM_FLAG)
    5 = optical loading
    6 = counting-mode exposure problems
   -3 = flag12=T
  

Number_Events
The number of flares or other "events" identified in the X-ray light-curve for the specified observation, as derived by the present authors.

Notes
Notes on the properties of the star, etc., made by the present authors.

Ref_Star
Selected reference(s) for the specified star, written in a concise form, e.g, 'Koen+ 2002'. The full references corresponding to these short-forms are available at http://cdsarc.u-strasbg.fr/ftp/cats/J_A+A/581/A28/refs.dat.

Ref_XMM_Result
Reference(s) to the XMM-Newton results on the specified star, written in a concise form, e.g, 'Koen+ 2002'. The full references corresponding to these short-forms are available at http://cdsarc.u-strasbg.fr/ftp/cats/J_A+A/581/A28/refs.dat.

TwoXMM_Summary_URL
The URL link to the 2XMM summary-results web page at LEDAS for the specified observation.

Event_Number
The event identifier: this is a consecutive number which identifies each event in a specific light-curve. For 80 ObsIDs there is only a single event in an observation, while there are 11 ObsIDs with 2 events, 8 ObsIDs with 3 events, 4 ObsIDS with 4 events, 2 ObsIDS with 5 events and 3 ObsIDs with 6 events.

Full_Profile_Flag
This flag parameter has the following possible values:

     Y:   TRUE, if event time profile is considered to be fully observed;
     N:   FALSE, if it is not considered to be fully observed.
  

Flare_Flag
This flag parameter is set to 'Y' if the observed event is considered to be a flare, else is set to 'N'.

Event_Type
The authors' estimate of the event type: flare, trend, gradual, indeterminate, or periodic. See Section 3.1 of the reference paper for a discussion of this characterization.

Event_SNR
The signal-to-noise ratio of the event over the time span given by the event duration parameter.

Quies_Fx
The source's quiescent level fq, i.e., the mean X-ray flux (presumably excluding the interval in which this event or other events occurred) in the total band, 0.2-12 keV, in erg cm-2 s-1, as estimated by the authors.

Peak_Fx
The peak X-ray flux fp of the event, over and above the source's quiescent level, in the total band, 0.2-12 keV, in erg cm-2 s-1, as estimated by the authors. Thus, the total X-ray flux of the event is fq + fp.

Peak_Over_Quies_Fx
The ratio R of the event's peak-to-quiescent X-ray fluxes, f_p/fq. Thus if R = 0.30, the total peak flux was 30% more than (1.30 times) the quiescent level.

Peak_Time
The time of the peak of the event. This was calculated by the HEASARC based on the start time of the observation and the time relative to the start of the observation when the peak occurred, both of which parameters were given in the original table.

Peak_Time_Relative
The time of the peak of the event relative to the start time of the observation, in seconds.

Rise_Time
The event rise time, defined as the time interval over which the count rate increased from Cmax / e to Cmax, where Cmax is is the count rate above the quiescent level at the peak, in seconds.

Fall_Time
The event decay time, defined as the time interval over which the count rate decreased from Cmax to Cmax / e, where Cmax is is the count rate above the quiescent level at the peak, in seconds.

Event_Duration
The event duration, defined as the time interval between the times in the rise and decay phases when the count rate was C_max/e, in seconds.

Quies_Lx
The luminosity corresponding to the quiescent level flux of the source during the observation, in the total band (0.2-12 keV), in erg s-1.

Peak_Lx
The luminosity corresponding to the peak flux of the source during the specified event, in the total band (0.2-12 keV), in erg s-1.

Event_Energy
The total-band emitted energy of the event over the time interval specified by the event duration, in erg.

Class
The HEASARC Browse object classification, based on the value of the spect_type parameter.


Contact Person

Questions regarding the XMMT2FLARE database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Thursday, 17-Sep-2015 15:28:57 EDT