  There is a known tension between cosmological parameter constraints obtained
from the primary CMB and those from galaxy cluster samples. One possible
explanation could be certain types of groups or clusters of galaxy have been
missed in the past. We aim to search for galaxy groups and clusters with
particularly extended surface brightness distributions, by creating a new X-ray
selected catalog of extended galaxy clusters from the ROSAT All-Sky Survey,
using a dedicated algorithm optimized for extended sources. Through extensive
simulations, the detection efficiency and sample purity are investigated.
Previous cluster catalogs in X-ray and other wave-bands, as well as
spectroscopic and photometric redshifts of galaxies are used for the cluster
identification. We report a catalog of galaxy clusters at high galactic
latitude based on the ROSAT All-sky Survey, named as RXGCC, which includes 944
groups and clusters. Out of it, 641 clusters have been identified through ICM
emission previously (Bronze), 154 known optical and infrared clusters are
detected as X-ray clusters for the first time (Silver), and 149 identified as
clusters for the first time (Gold). Based on 200 simulations, the contamination
ratio of the detections which were identified as clusters by ICM emission, and
the detections which were identified as optical and infrared clusters in
previous work is 0.008 and 0.100, respectively. Compared with Bronze sample,
the Gold+Silver sample is less luminous, less massive, and has a flatter
surface brightness profile. Specifically, the median flux in [0.1-2.4]keV band
for Gold+Silver and Bronze sample is 2.496e-12 erg/s/cm^2 and 4.955e-12
erg/s/cm^2, respectively. The median slope of cluster profile is 0.76 and 0.83
for Gold+Silver and Bronze sample, respectively. This whole sample is available
at https://github.com/wwxu/rxgcc.github.io/blob/master/table_rxgcc.fits
(Abridged)
