J/ApJS/148/243 Catalog of clusters of galaxies from SDSS (Bahcall+, 2003)
A merged catalog of clusters of galaxies from
Early Sloan Digital Sky Survey Data.
Bahcall N.A., McKay T.A., Annis J., Kim R.S.J., Dong F., Hansen S., Goto T.,
Gunn J.E., Miller C., Nichol R.C., Postman M., Schneider D., Schroeder J.,
Voges W., Brinkmann J., Fukugita M.
<Astrophys. J. Suppl. Ser. 148, 243 (2003)>
=2003ApJS..148..243B 2003ApJS..148..243B
ADC_Keywords: Clusters, galaxy ; Redshifts
Keywords: catalogs - cosmology: observations - cosmology: theory -
galaxies: clusters: general - large-scale structure of universe
Abstract:
We present a catalog of 799 clusters of galaxies in the redshift range
zest=0.05-0.3 selected from ∼400deg2 of early Sloan Digital Sky
Survey (SDSS) commissioning data along the celestial equator. The
catalog is based on merging two independent selection methods - a
color-magnitude red-sequence maxBCG technique (B), and a hybrid
matched filter method (H). The BH catalog includes clusters with
richness Λ≥40 (matched filter) and Ngal≥13 (maxBCG),
corresponding to typical velocity dispersion of σv≳400km/s
and mass (within 0.6h-1Mpc radius) ≳5x1013h-1M☉. This
threshold is below Abell richness class 0 clusters. The average space
density of these clusters is 2x10-5h3/Mpc3. All NORAS
(J/ApJS/129/435) X-ray clusters and 53 of the 58 Abell clusters in
the survey region are detected in the catalog; the five additional
Abell clusters are detected below the BH catalog cuts. The cluster
richness function is determined and found to exhibit a steeply
decreasing cluster abundance with increasing richness. We derive
observational scaling relations between cluster richness and observed
cluster luminosity and cluster velocity dispersion; these scaling
relations provide important physical calibrations for the clusters.
The catalog can be used for studies of individual clusters, for
comparisons with other sources such as X-ray clusters and active
galactic nuclei, and, with proper correction for the relevant
selection functions, also for statistical analyses of clusters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 91 799 *BH SDSS cluster catalog
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Note on catalog.dat: General comments to catalog:
(HMF = Hybrid Matched Filter detection method)
1: zest=0.05-0.3; 379°2 covering the area
RA(2000)=355° to 56° and 145.3° to 236.0°,
DE(2000)=-1.25° to 1.25°.
2: All HMF clusters with Λ≥40, maxBCG clusters with NGal≥13,
and their matches are included (see #4 below).
3: Some detections are false-positives, i.e., non-real clusters (Section 5);
all are included in order to avoid unquantitative visual selection.
4: Cluster matches are algorithmically defined as B and H clusters separated
by ≤1h-1Mpc (projected) and Δzest≤0.08 (2.5-σ). All
matching clusters with NGal≥6 and Λ≥20 are included.
5: The same cluster is sometimes listed as two separate H and B clusters
(i.e., 'un-matched') if the separation is Δzest>0.08 or >1h-1Mpc
(due to uncertainties in zest and the different definitions of cluster
'center'). (If one of the 'un-matched' clusters is below the catalog
richness or redshift cuts, it will not be listed in the catalog.)
6: Occasionally, a single H or B cluster may be split by the detection
algorithm into two separate clusters; this may represent sub-structure
in larger systems.
7: HMF clusters are typically centered on a mean high overdensity region of
galaxies; maxBCG clusters center on a galaxy with a color and magnitude
estimated as likely to be a BCG. Some B clusters thus center on a bright
galaxy or small group of red galaxies in the outskirts of clusters. (This
can cause splitting of a cluster match into two or more separate listings;
see #5).
This may also represent sub-structure in or near clusters.
8: Some systems may represent parts of extended large-scale structure
rather than condensed virialized clusters.
9: The catalog is not volume limited. Selection functions as a function of
redshift and richness are provided in Section 5.
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See also:
J/ApJS/129/435 : NORAS galaxy cluster survey. I. (Bohringer+, 2000)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [BMA2003] The BH SDSS cluster number
5- 7 A3 --- Meth Method of detection (1)
10- 16 F7.3 deg RAHdeg ? HMF Right Ascension expressed
in decimal degrees (J2000)
17- 23 F7.3 deg DEHdeg ? HMF Declination expressed
in decimal degrees (J2000)
26- 29 F4.2 --- zHMF ? The HMF redshift estimate
32- 35 F4.1 --- Lambda ? The HMF cluster richness
38- 44 F7.3 deg RABdeg ? The maxBCG Right Ascension expressed
in decimal degrees (J2000)
45- 51 F7.3 deg DEBdeg ? The maxBCG Declination expressed
in decimal degrees (J2000)
54- 58 F5.3 --- zBCG ? The maxBCG redshift estimate
61- 62 I2 --- NGal ? The maxBCG richness estimate
65- 69 F5.3 --- zspec ? SDSS spectroscopic redshift
73- 92 A20 --- n_[BMA2003] Additional comments on [BMA2003]
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Note (1): Method of detection:
H = HMF (Hybrid Matched Filter);
B = maxBCG (Brightest Cluster Galaxy);
h or b = cluster match outside the catalog richness or redshift
thresholds, i.e., Λ<40, NGal<13, z>0.3.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 24-Oct-2003