WARPS2 - Wide Angle ROSAT Pointed Survey, Second Phase (WARPS-II) Clusters Catalog

Overview

This table contains the galaxy cluster catalog from the second, larger phase of the Wide Angle ROSAT Pointed Survey (WARPS), an X-ray selected survey for high-redshift galaxy clusters. WARPS is among the largest deep X-ray cluster surveys and is being used to study the properties and evolution of galaxy clusters. The WARPS-II sample contains 125 clusters serendipitously detected in a survey of 301 ROSAT PSPC pointed observations and covers a sky area of 56.7 deg². Of these 125 clusters, 53 have not been previously reported in the literature. The authors have nearly complete spectroscopic follow-up of the clusters, which range in redshift from z = 0.029 to z = 0.92 with a median redshift of z = 0.29 and they find 59 clusters with z >= 0.3 (29 not previously reported in the literature) and 11 clusters with z >= 0.6 (6 not previously reported). They also define a statistically complete subsample of 102 clusters above a uniform flux limit of 6.5 x 10^-14 ergs/cm²/s (0.5 - 2.0 keV). In their paper, the authors also compare their redshifts, fluxes, and detection methods to other similar published cluster surveys and state that they find no serious issues with their measurements or completeness.

The list of ROSAT pointings used in WARPS-II is given in Table 1 of the first reference paper. The WARPS-I cluster catalog (the second reference listed below) is also available in Browse as the WARPS table.

Catalog Bibcode

2008ApJS..176..374H

References

The WARPS survey. VII. The WARPS-II cluster catalog.
    Horner D.J., Perlman E.S., Ebeling H., Jones L.R., Scharf C.A., Wegner G.,
    Malkan M., Maughan B.
   <Astrophys. J. Suppl. Ser., 176, 374-413 (2008)>
   =2008ApJS..176..374H
The WARPS survey. VI. Galaxy cluster and source identifications from phase I.
    Perlman E.S., Horner D.J., Jones L.R., Scharf C.A., Ebeling H., Wegner G.,
    Malkan M.
   <Astrophys. J. Suppl. Ser. 140, 265 (2002)>
   =2002ApJS..140..265P

Provenance

This table was created by the HEASARC in September 2010 based on the combination of the electronic versions of Tables 2, 3, and 4 from the first reference paper which were obtained from the CDS (their catalog J/ApJS/176/374).

HEASARC Implementation

The HEASARC has added a parameter called source_sample (q.v.) to allow users to easily identify from which sample (Table 2: the WARPS-II statistically complete, flux-limited sample or Table 3, the WARPS-II additional clusters and candidates) a given source was taken.

Parameters

Name
The assigned cluster name, of the J2000.0-based form 'WARPS JHHMM.m+DDMMA' recommended by the Dictionary of Nomenclature of Celestial Objects (superceding the form 'WARP JHHMM.m+DDMMA' used in the paper itself), where 'A' is used to differentiate a few spatially close clusters and can be either 'E' or 'W'. Many WARPS-II clusters have been previously identified, mostly by other serendipitous cluster surveys similar to WARPS (see Section 4 of the reference paper). The known aliases for WARPS-II clusters (usually listed as they appear in NED) are given in the alt_names parameter.

RA
The Right Ascension of the WARPS-II cluster in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-4 degrees in the original table.

Dec
The Declination of the WARPS-II cluster in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-4 degrees in the original table.

LII
The Galactic Longitude of the WARPS-II cluster.

BII
The Galactic Latitude of the WARPS-II cluster.

NH_Galactic
The Galactic hydrogen column density in the direction of the WARPS-II cluster, in cm^-2, taken from Dickey & Lockman, (1990, ARA&A, 28, 215).

Flux
The unabsorbed source flux in the 0.5-2.0 keV energy band, in erg cm^-2 s^-1. The authors calculated the final flux from the total count rate using the same iterative method as Ebeling et al. (1998, MNRAS, 301, 881). They assume a Raymond-Smith spectrum with the measured cluster redshift (see Section 2.3 of the reference paper), a metal abundance of 0.3 solar, and the hydrogen column density for the cluster coordinates from Dickey & Lockman (1990, ARAA, 28, 215). The temperature of the model was derived iteratively by constraining the cluster to obey the L - T relation, T_X in keV = 2.76 L_bol^0.33 (White et al. 1997, MNRAS, 292, 419).

Log_Lx_50
The logarithm of the rest-frame source luminosity of the cluster in the 0.5-2.0 keV band derived in the same manner as the flux, in erg s^-1. This was derived assuming a cosmology in which q = 0.5 and H₀ = 50 km s^-1 Mpc^-1.

Log_Lx
The logarithm of the rest-frame source luminosity of the cluster in the 0.5-2.0 keV band derived in the same manner as the flux, in erg s^-1. This was derived assuming a cosmology in which H₀= 70 km s^-1 Mpc^-1, Omega_M=0.3 and Omega_Lambda=0.7.

Redshift
The redshift of the cluster.

Num_Redshifts
The number of galaxy redshifts used to derive the cluster redshift.

Redshift_Flag
This flag parameter is set to '?' to indicate that there is uncertainty in the number of valid galaxy redshifts used to derive the cluster redshift, or to '.5' in one case (WARPS J1117.5+0746) so as to indicate that, in addition to one good-quality galaxy redshift which was used (indicated by a num_redshifts value of 1), one low-quaility galaxy redshift was also used to calculate the cluster redshift (a value of 1.5 is given for the number of redshifts for this cluster in the published paper).

Core_Radius
The estimated core radius of the cluster, in arcseconds, assuming a King profile with beta = 2/3. Note that these should be interpreted with caution given the size of the ROSAT PSF. Clusters that the authors split on the basis of redshift or other information do not have measured core radii.

Notes
Notes or comments (if any) about the source. See Section 3.2 of the published paper for more details about many of these sources.

Alt_Names
The known aliases for the WARPS-II cluster (usually listed as they appear in NED).

Source_Sample
This parameter was added by the HEASARC in order to allow users to easily identify from which of the samples discussed in the reference paper a given source was taken. Sources which were in Table 2, the WARPS-II statistically complete, flux-limited sample, have been given source_sample values of 'Main', while those in Table 3, the WARPS-II additional clusters and candidates, have been given source_sample values of 'Other'.

Contact Person

Questions regarding the WARPS2 database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:36:38 EDT