REFLEX - ROSAT-ESO Flux-Limited X-Ray (REFLEX) Galaxy Cluster Survey

Overview

This table is the ROSAT-ESO Flux-Limited X-Ray (REFLEX) Galaxy Cluster Survey Catalog. The REFLEX Cluster Survey provides information on the X-ray properties, redshifts, and some identification details of clusters in the REFLEX sample. The catalog describes a statistically complete X-ray flux-limited sample of 447 galaxy clusters above an X-ray flux of 3 x 10^-12 erg/s/cm² (0.1 to 2.4 keV) in an area of 4.24 steradians in the southern sky. The cluster candidates were first selected by their X-ray emission in the ROSAT-All Sky Survey and subsequently spectroscopically identified in the frame of an ESO key program. Previously described tests have shown that the sample is more than 90% complete and there is a conservative upper limit of 9% on the fraction of clusters with a dominant X-ray contamination from AGN. This data set is at present the largest, statistically complete X-ray galaxy cluster sample. The sample forms the basis of several cosmological studies, one of the most important applications being the assessment of the statistics of the large-scale structure of the universe and the test of cosmological models.

The X-ray luminosities and other distance-dependent cluster parameters are calculated for a Lambda cosmology with a Hubble Constant H₀ of 70 km/s/Mpc, Omega_M of 0.3, and Omega_Lambda of 0.7. The CDS version of this catalog contains an additional table (reflex50.dat) with these parameters calculated for an Einstein-de Sitter universe with H₀ = 50 km/s/Mpc, Omega_M = 1.0, and Omega_Lambda = 0.0.

Catalog Bibcode

2004A&A...425..367B

References

The ROSAT-ESO Flux Limited X-ray (REFLEX) Galaxy Cluster Survey.
V. The cluster catalogue.
    Boehringer H., Schuecker P., Guzzo L., Collins C.A., Voges W.,
    Cruddace R.G., Ortiz-Gil A., Chincarini G., De  Grandi S., Edge A.C.,
    MacGillivray H.T., Neumann D.M., Schindler S., Shaver P.
   <Astron. Astrophys. 425, 367 (2004)>
   =2004A&A...425..367B

Provenance

This table was created by the HEASARC in October 2004 based on CDS tables J/A+A/425/367/reflex70.dat and J/A+A/425/367/reflex.dat.

HEASARC Implementation

The HEASARC version of the REFLEX Catalog contains the X-ray luminosities and other distance-dependent cluster parameters as calculated for a Lambda cosmology with a Hubble Constant H₀ of 70 km/s/Mpc, Omega_M of 0.3, and Omega_Lambda of 0.7. The CDS version of this catalog contains an additional table (reflex50.dat) with these parameters calculated for an Einstein-de Sitter universe with H₀ = 50 km/s/Mpc, Omega_M = 1.0, and Omega_Lambda = 0.0.

Notice that the HEASARC converted the error in the X-ray flux (flux_error) from the relative form in which it was given in the published form of the catalog (and the CDS table) to its absolute value, so as to conform to the standard HEASARC convention for error parameters. The HEASARC also changed the value of '*' in the note_flags parameter to 'A' to avoid confusion with the wild-card value used by Browse.

Parameters

Name
The REFLEX designation for the cluster.

Alt_Name
An alternate previous designation for the cluster, where for some of the smaller galaxy groups the name refers to the central dominant galaxy in the group, e.g., by the NGC name of this galaxy.

Note_Name
A flag indicating the presence of a note about the specified cluster using the following key:

  Value: Meaning

      a: Cl0053-37
      b: cluster from the catalogue of Wegner et al.
         (1996, CDS Cat. <J/ApJS/106/1>, 1999, Cat. <J/MNRAS/305/259>)
      c: from the ROSAT Bright Source Catalogue (Fischer et al. (1998) and
         Schwope et al. (2000), both as CDS Cat. <IX/32>)
      d: RASSCALS145
      e: ZwCl0258.9+0142
      f: cluster from the catalogue by Dalton et al. (1994,
         CDS Cat. <J/MNRAS/269/151>, 1997, Cat. <J/MNRAS/289/263>)
      g: Eridanus group
      h: ES0657-558
      i: AM 0711-602
      j: USZ-SSRS2-group from the catalogue of Ramella et al. (2002,
         CDS Cat. <J/AJ/123/2976>)
      k: MS1111.8-3754
      l: MS1306.7-0121
      m: ZwCl1703.8-0129
      n: AM 2108-232
      o: MS 2215.7-0404
      p: AM 2250-633

RA
The Right Ascension of the cluster in the specified equinox. This was given in J2000 coordinates and to a precision of 0.1 seconds of time in the original table.

Dec
The Declination of the cluster in the specified equinox. This was given in J2000 coordinates and to a precision of 1 arcsecond in the original table.

LII
The Galactic Longitude of the cluster.

BII
The Galactic Latitude of the cluster.

Redshift
The redshift of the cluster.

Num_Z_Galaxies
The number of galaxies from which the redshift has been determined after the rejection of non-members: a zero means that no information is available about the number of galaxies used to determine the cluster redshift.

Flux
The measured, unabsorbed X-ray flux of the cluster in the 0.1 - 2.4 keV band, in erg/s/cm². This value has been corrected for column density, X-ray temperature, and K-Correction effects. Notice that this is not the nominal X-ray flux used to define the flux limit of REFLEX: the latter is available as the nominal_flux parameter in this table.

Flux_Error
The error in the measured, unabsorbed X-ray flux in the 0.1 - 2.4 keV band, in erg/s/cm². Notice that the HEASARC converted this error from the relative form in which it was given in the published form of the catalog (and the CDS table) to its absolute value, so as to conform to the standard HEASARC convention for error parameters.

Lx_Obs
The X-ray luminosity detected within the measurement aperture, i.e., uncorrected for any missing flux, in the rest frame 0.1 - 2.4 keV band, in erg/s.

Aperture_Ang_Radius
The aperture radius within which the X-ray count rate and flux were determined (the radius where the plateau value is reached in the cumulative count rate curve of the Growth Curve Analysis or GCA method), in arcminutes.

Lx
The X-ray luminosity in the 0.1-2.4 keV band corrected for the estimated flux lost outside the measurement aperture, in erg/s.

NH_Gal
The Galactic Hydrogen column density in the line-of-sight, in H atoms/cm², as obtained from the 21-cm observations of Dickey and Lockman (1990, ARA&A, 28, 215) and Stark et al. (1992, ApJS, 79, 77).

Note_Flags
This parameter contains flags indicating different analysis and/or other comments, as follows:

  Value: Meaning

      B: clusters blended with point sources or double clusters which
          were deblended
      X: clusters where the details of the source identification are
          commented in Section 7 of the paper
      D: double clusters discussed in section 8 of the paper
      L: clusters which are too extended for the standard GCA count rate
          determination in 2x2 square degree fields, and therefore were analyzed
          in 4x4 or 8x8 square degree fields
      P: parts of close cluster pairs or groups
      A: cluster origin of the X-ray emission is not completely certain
          as detailed in Section 7 of the paper

Ref_Redshift
Reference codes to literature values for the cluster redshifts: the key to these codes is given in the file https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/425/367/refs.dat.

Count_Rate
The cluster count rate, in counts per second, as measured with the GCA method and for the aperture size as given by the aperture_ang_radius parameter, i.e., uncorrected for the `missing flux', in the 0.5-2.0 keV band.

Nominal_Flux
The nominal X-ray flux in the 0.1-2.4 keV band, in erg/s/cm², as determined in the first step for an assumed temperature T_x of 5 keV and z of 0, which values were used for the source selection.

Num_Photons
The number of source photons detected in the 0.5-2.0 keV band and in the reference aperture, i.e., uncorrected for any missing flux.

Log_Point_Src_Prob
The probability for the X-ray source to be a point source given as log10(P), where the way that P is calculated is described in Section 5 of the paper. Notice that this parameter is given as -log10(P) in the published paper, but as log10(P) in both the CDS and HEASARC versions of the catalog.

Best_Fit_Core_Radius
The best-fit core radius, in arcminutes, for the beta-model fit. Note that the core radii determined in this study are only a qualitative measure of the source extents, since the errors were very large and the fitting grid was coarsely spaced. The catalog authors recommend that these results not be used as quantitative estimates of cluster shapes at this point.

Minimal_Core_Radius
The minimal core radius, in arcminutes, which is consistent within 2-Sigma error limits. Note that the core radii determined in this study are only a qualitative measure of the source extents, since the errors were very large and the fitting grid was coarsely spaced. The catalog authors recommend that these results not be used as quantitative estimates of cluster shapes at this point.

Hardness_Ratio
The X-ray source Hardness Ratio as determined from the count rates in the soft (ROSAT PSPC channels 11 - 40) and hard (ROSAT PSPC channels 52 - 201) band and the formula HR = (H-S)/(H+S), where H is the hard-band (0.5-2.0 keV) count rate and S is the soft-band (0.1-0.4 keV) count rate.

Hardness_Ratio_Error
The 1-Sigma Poisson error in the Hardness Ratio.

Delta_Hardness_Ratio
The deviation of the measured Hardness Ratio from the expectation value calculated for the given column density and an assumed temperature of 5 keV, given in units of sigma from the Poisson statistics.

Aperture_Radius
The aperture radius within which the source count rate was measured, i.e., the radius where the cumulative source count rate profile reached the plateau value, in physical units of Mpc.

Contact Person

Questions regarding the REFLEX database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:33:42 EDT