The GMBCG cluster catalog for SDSS DR7 covers the legacy
survey area of SDSS and spanning a redshift range from 0.1 to 0.55. The
catalog consists of over 55,000 rich clusters and is approximately
volume limited up to redshift 0.40.
This catalog is an extension of the maxBCG cluster catalog for SDSS
(Koester et al 2007) to redshift beyond 0.3 and covers slightly more
sky area too (~ 8000 square deg).
maxBCG matches the assumed model cluster filter to select clusters while GMBCG detects clusters by looking at the difference between cluster and background in color space. It is a kind of differential detection compared to maxBCG. Details about the cluster finding algorithm and the catalog can be found from Hao et al 2010.
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- Data: The clusters are indexed by BCGs and can be download from here:
- Important: Please visit our blog for latest updates on the catalogs
- gmbcg_sdss_dr7_public_cluster_catalog (fit format)
Earth kmz file: You
can open them using Google Earth and fly around the clusters. Click here to see our webpage for Google Earth.
- kmz file for 3,000 clusters from the public catalog
- kmz file for 100 rich clusters at redshift below 0.1 (not in
the public catalog)
- ObjID: unique
id of the BCG. Some of the objids are not
long64 type, which are
due to a known bug in the sdss dr7 database. We will update the objid
after that bug is fixed. For now, matching object using ra/dec is
- RA: 0 - 360 degree (J2000)
- DEC: (J2000)
- Photoz: photometric redshift
- Photoz_err: errors of photoz
- SPZ: spectroscopic redshift of BCG
- gmr: g-r color
- gmr_err: measurement errors for g-r
- rmi: r-i color
- rmi_err: measurement
errors for r-i
- model_mag: 5 band
magnitude after correction for reddening
- model_mag_err: 5 band (u,g,r,i,z)
model magnitude errors
- S_cluster: clustering strength
- GM_Scaled_Ngals: richness
- GM_Ngals_weighted: weighted richness
- WeightOK: if it is set to
1, weighted richness is recommended.
- model_mag in this format is given as: dered_u, dered_g, dered_r, dered_i, dered_z
- model_mag_err in this format is given
as: u_Err, g_Err, r_Err, i_Err, z_Err.
Last updated 11/29/10