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تسجيل مستخدم جديدIdentifying galaxy groups at high redshift from incomplete spectroscopic data: I. The group finder and application to zCOSMOS
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Identifying galaxy groups from redshift surveys of galaxies plays an important role in connecting galaxies with the underlying dark matter distribution. Current and future high-$z$ spectroscopic surveys, usually incomplete in redshift sampling, present both opportunities and challenges to identifying groups in the high-$z$ Universe. We develop a group finder that is based on incomplete redshift samples combined with photometric data, using a machine learning method to assign halo masses to identified groups. Test using realistic mock catalogs shows that $gtrsim 90%$ of true groups with halo masses $rm M_h gtrsim 10^{12} M_{odot}/h$ are successfully identified, and that the fraction of contaminants is smaller than $10%$. The standard deviation in the halo mass estimation is smaller than 0.25 dex at all masses. We apply our group finder to zCOSMOS-bright and describe basic properties of the group catalog obtained.
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