http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
ACTIVITY IN GALACTIC NUCLEI OF COMPACT GROUP GALAXIES IN THE LOCAL UNIVERSE
Sohn, Jubee,Hwang, Ho Seong,Lee, Myung Gyoon,Lee, Gwang-Ho,Lee, Jong Chul IOP Publishing 2013 The Astrophysical journal Vol.771 No.2
<P>We study the nuclear activity of galaxies in local compact groups. We use a spectroscopic sample of 238 galaxies in 58 compact groups from the Sloan Digital Sky Survey data release 7 to estimate the fraction of active galactic nucleus (AGN) host galaxies in compact groups, and to compare it with those in cluster and field regions. We use emission-line ratio diagrams to identify AGN host galaxies and find that the AGN fraction of compact group galaxies is 17%-42% depending on the AGN classification method. The AGN fraction in compact groups is not the highest among the galaxy environments. This trend remains even if we use several subsamples segregated by galaxy morphology and optical luminosity. The AGN fraction for early-type galaxies decreases with increasing galaxy number density, but the fraction for late-type galaxies changes little. We find no mid-infrared detected AGN host galaxies in our sample of compact groups using Wide-field Infrared Survey Explorer data. These results suggest that the nuclear activity of compact group galaxies (mostly early types) is not strong because of lack of gas supply even though they may experience frequent galaxy-galaxy interactions and mergers that could trigger nuclear activity.</P>
The HectoMAP Cluster Survey. II. X-Ray Clusters
Sohn, Jubee,Chon, Gayoung,Bö,hringer, Hans,Geller, Margaret J.,Diaferio, Antonaldo,Hwang, Ho Seong,Utsumi, Yousuke,Rines, Kenneth J. American Astronomical Society 2018 The Astrophysical journal Vol.855 No.2
<P>We apply a friends-of-friends algorithm to the HectoMAP redshift survey and cross-identify associated X-ray emission in the ROSAT All-Sky Survey data (RASS). The resulting flux-limited catalog of X-ray cluster surveys is complete to a limiting flux of similar to 3 x 10(-13) erg s(-1) cm(-2) and includes 15 clusters (7 newly discovered) with redshifts z <= 0.4. HectoMAP is a dense survey (similar to 1200 galaxies deg(-2)) that provides similar to 50 members (median) in each X-ray cluster. We provide redshifts for the 1036 cluster members. Subaru/Hyper Suprime-Cam imaging covers three of the X-ray systems and confirms that they are impressive clusters. The HectoMAP X-ray clusters have an L-X-sigma(cl) scaling relation similar to that of known massive X-ray clusters. The HectoMAP X-ray cluster sample predicts similar to 12,000 +/- 3000 detectable X-ray clusters in RASS to the limiting flux, comparable with previous estimates.</P>
CATALOGS OF COMPACT GROUPS OF GALAXIES FROM THE ENHANCED SDSS DR12
Sohn, Jubee,Geller, Margaret J.,Hwang, Ho Seong,Zahid, H. Jabran,Lee, Myung Gyoon American Astronomical Society 2016 The Astrophysical journal Supplement series Vol.225 No.2
<P>We apply a friends-of-friends algorithm to an enhanced SDSS DR12 spectroscopic catalog, including redshift from the literature to construct a catalog of 1588 N >= 3 compact groups of galaxies containing 5178 member galaxies and covering the redshift range 0.01 < z < 0.19. This catalog contains 18 times as many systems and reaches 3 times the depth of the similar catalog of Barton et al. We construct catalogs from both magnitude-limited and volume-limited galaxy samples. Like Barton et al. we omit the frequently applied isolation criterion in the compact group selection algorithm. Thus the groups selected by fixed projected spatial and rest-frame line-of-sight velocity separation produce a catalog of groups with a redshift-independent median size. In contrast to previous catalogs, the enhanced SDSS DR12 catalog (including galaxies with r < 14.5) includes many systems with z less than or similar to 0.05. The volume-limited samples are unique to this study. The compact group candidates in these samples have a median stellar mass independent of redshift. Groups with velocity dispersion. less than or similar to 100 km s(-1) show abundant evidence for ongoing dynamical interactions among the members. The number density of the volume-limited catalogs agrees with previous catalogs at the lowest redshifts but decreases as the redshift increases. The SDSS fiber placement constraints limit the catalog's completeness. In spite of this issue, the volume-limited catalogs provide a promising basis for detailed spatially resolved probes of the impact of galaxy-galaxy interactions within similar dense systems over a broad redshift range.</P>