相关论文: Dark Matter Subhalos and the X-ray Morphology of t…
We present a 4 deg^2 weak gravitational lensing survey of subhalos in the very nearby Coma cluster using the Subaru/Suprime-Cam. The large apparent size of cluster subhalos allows us to measure the mass of 32 subhalos detected in a…
The dependence of flattening of galaxies on the density of galaxies in subclusters selected around galaxies NGC4889, NGC4874 and NGC4839 in the Coma cluster has been studied. The mean values of observed ratios of galaxy diameters and…
Various differences in galaxy cluster properties derived from X-ray and weak lensing observations have been highlighted in the literature. One such difference is the observation of mass concentrations in lensing maps which have no X-ray…
We construct an analytical model of the mass distribution function of subhalos in a galaxy cluster in the context of the cold dark matter (CDM) theory. Our model takes account of two important effects; the high density of the precluster…
In cold dark matter cosmological models, structures form and grow by merging of smaller units. Numerical simulations have shown that such merging is incomplete; the inner cores of halos survive and orbit as "subhalos" within their hosts.…
The Coma cluster is the richest and most compact of the nearby clusters, yet there is growing evidence that its formation is still on-going. With a new multi-slit imaging spectroscopy technique pioneered at the 8.2 m Subaru telescope and…
We study the physical properties of weak-lensing subhalos in the Coma cluster of galaxies using data from galaxy redshift surveys. The data include 12989 galaxies with measured spectroscopic redshifts (2184 from our MMT/Hectospec…
The large-scale distribution of globular clusters in the central region of the Coma cluster of galaxies is derived through the analysis of Hubble Space Telescope/Advanced Camera for Surveys data. Data from three different HST observing…
We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 x 10^14 solar masses and 4 x 10^15 solar masses, and…
We examine the structure and dynamics of the galaxies in the Coma cluster using a catalog of 552 redshifts including 243 new measurements. The velocity distribution is shown to be non-Gaussian due to structure associated with the group of…
We present a new multiwavelength analysis of the Coma cluster subclustering based on recent X-ray data and on a compilation of nearly 900 redshifts. We characterize subclustering using the Serna&Gerbal (1996) hierarchical method which makes…
We report $Suzaku$ X-ray observations of the dark subhalo associated with the merging group of NGC 4839 in the Coma cluster. The X-ray image exhibits an elongated tail toward the southwest. The X-ray peak shifts approximately $1'$ away from…
The Coma cluster of galaxies was observed with XMM-Newton in 12 partially overlapping pointings. We present here the resulting X-ray map in different energy bands and discuss the large scale structure of this cluster. Many point sources…
The properties of substructure in galaxy clusters, exquisitely probed by gravitational lensing, offer a stringent test of dark matter (DM) models. Combining strong- and weak-lensing data for massive clusters, we map their total mass --…
We have identified over 2000 well resolved cluster halos, and also their associated bound subhalos, from the output of a 1024^3 particle cosmological N-body simulation (of box size 320 h^-1 Mpc and softening length 3.2 h^-1 kpc). This has…
Luminous stars in background galaxies straddling the lensing caustic of a foreground galaxy cluster can be individually detected due to extreme magnification factors of $\sim 10^2$--$10^3$, as recently observed in deep HST images. We…
Six subclusters in the Coma cluster have been selected on the basis of a hierarchical clustering method that takes the gravitational interaction among galaxies into account. Of these, three main subclusters around the galaxies NGC 4889, NGC…
We describe a wavelet transform analysis of the ROSAT PSPC images of the Coma cluster. On small scales, ~< 1', the wavelet analysis shows substructure dominated by two extended sources surrounding the two brightest cluster galaxies NGC 4874…
We observed three massive subhalos in the Coma cluster with {\it Suzaku}. These subhalos, labeled "ID 1", "ID 2", and "ID 32", were detected with a weak-lensing survey using the Subaru/Suprime-Cam (Okabe et al. 2014a), and are located at…
Dark matter subhalos with extended profiles and density cores, and globular stars clusters of mass $10^6-10^8 M_\odot$, that live near the critical curves in galaxy cluster lenses can potentially be detected through their lensing…