Low X-Ray Luminosity Galaxy Clusters. IV. SDSS galaxy clusters at z < 0.2. (arXiv:1905.06410v1 [astro-ph.GA])

Low X-Ray Luminosity Galaxy Clusters. IV. SDSS galaxy clusters at z < 0.2. (arXiv:1905.06410v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+OMill_A/0/1/0/all/0/1">A.L. O&#x27;Mill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alonso_M/0/1/0/all/0/1">M.V. Alonso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Valotto_C/0/1/0/all/0/1">C. Valotto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Castellon_J/0/1/0/all/0/1">J.L. Nilo Castell&#xf3;n</a>

This is the fourth of a series of papers on low X-ray luminosity galaxy
clusters. The sample comprises 45 galaxy clusters with X-ray luminosities
fainter than 0.7 10$^{44}$ erg s$^{-1}$ at redshifts lower than 0.2 in the
regions of the Sloan Digital Sky Survey. The sample of spectroscopic members of
the galaxy clusters was obtained with the criteria: r$_p$ $le$ 1 Mpc and
$Delta V leq sigma$ using our $sigma$ estimates containing 21 galaxy
clusters with more than 6 spectroscopic members. We have also defined a sample
of photometric members with galaxies that satisfy r$_p le $ 1 Mpc, and $Delta
V leq $ 6000 kms including 45 galaxy clusters with more than 6 cluster
members.

We have divided the redshift range in three bins: $z leq 0.065$; 0.065 $<$ z $<$ 0.10; and z $ge$ 0.10. We have stacked the galaxy clusters using the spectroscopic sub-sample and we have computed the best RS linear fit within 1$sigma$ dispersion. With the photometric sub-sample, we have added more data to the RS obtaining the photometric 1$sigma$ dispersion relative to the spectroscopic RS fit. We have computed the luminosity function using the $1/V_{max}$ method fitting it with a Schechter function. The obtained parameters for these galaxy clusters with low X-ray luminosities are remarkably similar to those for groups and poor galaxy clusters at these lower redshifts.

This is the fourth of a series of papers on low X-ray luminosity galaxy
clusters. The sample comprises 45 galaxy clusters with X-ray luminosities
fainter than 0.7 10$^{44}$ erg s$^{-1}$ at redshifts lower than 0.2 in the
regions of the Sloan Digital Sky Survey. The sample of spectroscopic members of
the galaxy clusters was obtained with the criteria: r$_p$ $le$ 1 Mpc and
$Delta V leq sigma$ using our $sigma$ estimates containing 21 galaxy
clusters with more than 6 spectroscopic members. We have also defined a sample
of photometric members with galaxies that satisfy r$_p le $ 1 Mpc, and $Delta
V leq $ 6000 kms including 45 galaxy clusters with more than 6 cluster
members.

We have divided the redshift range in three bins: $z leq 0.065$; 0.065 $<$ z
$<$ 0.10; and z $ge$ 0.10. We have stacked the galaxy clusters using the
spectroscopic sub-sample and we have computed the best RS linear fit within
1$sigma$ dispersion. With the photometric sub-sample, we have added more data
to the RS obtaining the photometric 1$sigma$ dispersion relative to the
spectroscopic RS fit. We have computed the luminosity function using the
$1/V_{max}$ method fitting it with a Schechter function. The obtained
parameters for these galaxy clusters with low X-ray luminosities are remarkably
similar to those for groups and poor galaxy clusters at these lower redshifts.

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