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M33XMM2 - M33 XMM-Newton X-Ray Variability Source Catalog

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Overview

This table contains the summary results of an analysis of the individual observations (24 archival raster observations) of a deep XMM-Newton survey of the Local Group spiral galaxy M33. The authors detected a total of 350 sources with fluxes (in the 0.2 - 4.5 keV energy band) in the range from 6.7 x 10^-16 to 1.5 x 10^-11 erg/cm^2/s. This comprehensive study considered flux variability, spectral characteristics, and classification of the detected objects. Thirty-nine objects in the catalog are new sources, while 311 were already detected in a previous analysis of most of the same data using combined images. The authors present improved positions of these sources, ans also systematically searched for flux variability on time scales of hours to months or years. The detected variability was then used to classify 8 new X-ray binary candidates in M33. Together with the hardness ratio method and cross-correlation with optical, infrared, and radio data, the authors also classified or confirmed previous classification of 25 supernova remnants and candidates, 2 X-ray binaries, and 11 super-soft source candidates (7 of which are new SSS candidates). In addition, they classified 13 active galactic nuclei and background galaxies, 6 stars, and 23 foreground star candidates in the direction of M33. A further 206 objects are classified as 'hard', approximately half of which are sources intrinsic to M33. The relative contribution of the classified XRB and SSS in M33 is now comparable to M31. The luminosity distribution of SNRs in both spiral galaxies is almost the same, although the number of the detected SNRs in M33 remains much higher.

Catalog Bibcode

2006A&A...448.1247M

References

XMM-Newton survey of the Local Group galaxy M33.
Variability of the detected sources.
    Misanovic Z., Pietsch W., Haberl F., Ehle M., Hatzidimitriou D.,
    Trinchieri G
   <Astron. Astrophys. 448, 1247 (2006)>
   =2006A&A...448.1247M

Provenance

This table was created by the HEASARC in March 2007 based on the CDS table J/A+A/448/1247 file table4.dat. The CDS has another table which lists the properties of the sources detected on an observation-by-observation basis which is not included as part of this Browse table but is available at ftp://cdsarc.u-strasbg.fr/pub/cats/J/A+A/448/1247/table5.dat.gz

Parameters

Source_Number
A running number for the X-ray source in order of increasing J2000.0 Right Ascension.

Name
The name of the X-ray source using the '[MPH2006]' prefix followed by the X-ray source number, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects.

Alt_Name
An alternative designation for the X-ray source, when available, from Pietsch et al. (2004, CDS Cat. <J/A+A/426/11>), using the prefix of '[PMH2004]' followed by the X-ray source number, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects for sources listed in this reference.

RA
The Right Ascension of the source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.01 seconds of time in the original table. The authors determined the relative shifts between their overlapping observations using the positions of the common sources. Sources were considered detected in two different fields if their positions were closer than 3 times the combined statistical errors. They corrected all X-ray positions relative to the observation 0141980801 (1c), since the X-ray source positions in this observation showed the smallest offset with respect to optical and infrared counterparts in their preliminary analysis. Moreover, this field has sources in common with all other fields.

Dec
The Declination of the source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.1 arcseconds in the original table. The authors determined the relative shifts between their overlapping observations using the positions of the common sources. Sources were considered detected in two different fields if their positions were closer than 3 times the combined statistical errors. They corrected all X-ray positions relative to the observation 0141980801 (1c), since the X-ray source positions in this observation showed the smallest offset with respect to optical and infrared counterparts in their preliminary analysis. Moreover, this field has sources in common with all other fields.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Error_Radius
The total positional error, in arcseconds, which includes the statistical error and a systematic error of 0.5 arcseconds quadratically summed.

Flux_Max
The maximum EPIC flux, in erg/cm^2/s, of the X-ray source in the different observations in the XID band (0.2 - 4.5 keV), calculated from the vignetting-corrected count rate using the energy conversion factors (ECF) for the PN and MOS medium, thin and thick filter, obtained by W3PIMMS, taking 100% of the source counts and assuming a power-law spectrum with a photon index of 1.7 absorbed by the Galactic foreground column of 6 x 10^20 cm^-2. The various ECFs are listed in Table 3 of the reference paper. The assumed spectral model fits the majority of the sources in the sample well. i.e., XRBs, AGN, or "hard" sources, while it leads to an underestimation of the flux of soft sources (SNR, foreground stars, SSSs) by approximately 10-20%, or even higher for extremely soft sources like SSSs, especially if they are detected only in MOS data.

Flux_Max_Error
The error in the maximum EPIC flux, in erg/cm^2/s.

Var_Factor
The variability factor V of the X-ray source. V is defined as F _max/F_min where F_max and F_min are the maximum and minimum source fluxes in the XID band. If the source was not detected at the minimum level, then F_min was determined as the 3-sigma upper limit to the XID flux.

Var_Significance
The variability significance S for the X-ray source. S is defined as (F_max - F_min)/sqrt(sigma_max^2 + sigma_min^2), where sigma_max and sigma_min are the errors in F_max and F_min, respectively.

Var_Factor_Flag
The variability flag V_FLAG is set to 1 to indicate that the minimum XID flux was a non-detection, while for cases where the minimum XID flux was a detection, it is set to 0.

Alt_Names_Comments
Alternative X-ray identifications for the X-ray source from cross-correlations with sources detected in earlier surveys of M 33, and brief comments on X-ray variability and other information on the sources presented in these catalogs, as follows:

     X-n  = Long et al., 1981ApJ...246L..61L;
            Trinchieri et al., 1988ApJ...329.1037T
     SBn  = Schulman & Bregman, 1995ApJ...441..568S
     LCBn = Long et al., 1996ApJ...466..750L
     DCL97= Dubus et al., 1997ApJ...490L..47D
     DCL99= Dubus et al., 1999MNRAS.302..731D
     HPn  = Haberl & Pietsch, 2001A&A...373..438H
  

USNOB1_Name
The USNO-B1 counterpart to the X-ray source obtained from positional cross-correlation.

Log_Fx_Fopt
The logarithm of the ratio of the X-ray flux to the optical flux for the source (the latter using the USNO-B1 data).

TwoMASS_Name
The 2MASS counterpart to the X-ray source obtained from positional cross-correlation.

Jmag
The 2MASS J magnitude of the IR counterpart to the X-ray source.

Hmag
The 2MASS H Magnitude of the IR counterpart to the X-ray source.

Kmag
The 2MASS K Magnitude of the IR counterpart to the X-ray source.

NVSS_Name
The NVSS counterpart to the X-ray source obtained from positional cross-correlation.

Flux_21_cm
The NVSS 1.4-GHz flux density, in mJy, of the radio counterpart to the X-ray source.

Source_Type
A classification of the X-ray source, first used by Pietsch et al. (2004, A&A, 426, 11 = PMH2004), and discussed in detail in Section 9 of the reference paper, as follows:

     fgStar   = foreground star
     <fgStar> = foreground star candidate
     AGN      = active galactic nucleus
     <AGN>    = AGN candidate
     GAL      = galaxy
     <GAL>    = galaxy candidate
     SSS      = supersoft source in M33
     <SSS>    = supersoft source candidate in M33
     SNR      = supernova remnant in M 33
     <SNR>    = supernova remnant candidate in M33
     XRB      = X-ray binary in M 33
     <hard>   = HR2 - sigma_HR2 > -0.2, or only HR3 and HR4 defined,
                and no other classification (See PMH2004 for HRn definitions)
  

Additional_Comments
Additional comments and other identifications for the X-ray source or its counterpart in other energy bands, with their associated references, as follows:

      SIM           = SIMBAD Database
      NED           = NASA Extragalactic Database
      NVSS          = Condon et al., 1998AJ....115.1693C
      CS82          = Christian & Schommer, 1982ApJ...253L..13C
      [MC83]25      = Massey & Conti, 1983ApJ...273..576M
      IFM*          = Ivanov et al., 1993ApJS...89...85I
      GKLn          = Gordon et al., 1998ApJS..117...89G
      GDKn          = Gordon et al., 1999ApJS..120..247G
      TYC2293-810-1 = Hog et al., 1998A&A...335L..65H
      IV74          = Israel & van der Kruit, 1974A&A....32..363I
      VBW78         = von Kap-Herr et al., 1978A&A....62...51V
      M98           = Massey, 1998ApJ...501..153M
      MCM2001       = Magrini et al., 2001A&A...367..498M
      MBH96         = Massey et al., 1996ApJ...469..629M
      PMM2004       = Pietsch et al., 2004A&A...413..879P
      GM94          = Giovagnoli & Mould, 1994PASP..106..376G
      FS95b         = Fabrika et al., 1995Ap&SS.226..229F
      FSZ           = Fabrika et al., 1997BSAO...43..133F
      D33           = Macri et al., 2001AJ....121..870M;
                      Mochejska et al., 2001AJ....121.2032M
      RW93          = Regan & Wilson, 1993AJ....105..499R
      VHK           = Hubble, 1926ApJ....63..236H
      CGC97         = Crampton et al., 1997AJ....114.2353C
      BCLMP         = Boulesteix et al., 1974A&A....37...33B
  

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


Contact Person

Questions regarding the M33XMM2 database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 18-May-2007