Related papers: Compact groups in theory and practice - I. The spa…
We set out to quantify the number density of quiescent massive compact galaxies at intermediate redshifts. We determine structural parameters based on i-band imaging using the CFHT equatorial SDSS Stripe 82 (CS82) survey (~170 sq. degrees)…
We study the evolution of the stellar and dark matter components in a galaxy cluster of $10^{15} \, \rm{M_{\odot}}$ from $z=3$ to the present epoch using the high-resolution collisionless simulations of Ruszkowski & Springel (2009). At…
We use the Illustris Simulations to gain insight into the build-up of the outer, low-surface brightness regions which surround galaxies. We characterize the stellar haloes by means of the logarithmic slope of the spherically-averaged…
We utilize the galaxy shape catalogue from the first-year data release of the Subaru Hyper Suprime-cam Survey (HSC) to study the dark matter content of galaxy groups in the Universe using weak lensing. We use galaxy groups from the Galaxy…
Recent progress is summarized on the determination of the density distributions of stars and dark matter, stellar kinematics, and stellar population properties, in the extended, low surface brightness halo regions of elliptical galaxies.…
We present a dynamical analysis to infer the structural parameters and properties of the two nearby, compact, high velocity dispersion galaxies MRK1216 & NGC1277. Combining deep HST imaging, wide-field IFU stellar kinematics, and…
We use the Millennium Simulation, and an abundance-matching framework, to investigate the dynamical behaviour of galaxy pairs embedded in a cosmological context. Our main galaxy-pair sample, selected to have separations under 250 kpc/h,…
We present results from a systematic investigation of the X-ray properties of a sample of moderate redshift (0.3<z<0.6) galaxy groups. These groups were selected not by traditional X-ray or optical search methods, but rather by an…
Motivated by the presence of numerous dark matter clumps in the Milky Way's halo as expected from the cold dark matter cosmological model, we conduct numerical simulations to examine the heating of the disk. We construct an initial galaxy…
A study of the group properties of galaxies in our immediate neighborhood provides a singular opportunity to observationally constrain the halo mass function, a fundamental characterization of galaxy formation. Detailed studies of…
Compact groups (CGs) of galaxies are extreme environments for morphological transformations and the cessation of star formation. Though initially considered isolated, it is now recognised that many CGs are embedded in larger structures. We…
We derive the oblateness parameter q of the dark matter halo of a sample of gas rich, face-on disk galaxies. We have assumed that the halos are triaxial in shape but their axes in the disk plane (a and b) are equal, so that q=c/a measures…
A galaxy group catalog is constructed from the 2MASS Redshift Survey (2MRS) with the use of a halo-based group finder. The halo mass associated with a group is estimated using a `GAP' method based on the luminosity of the central galaxy and…
`Galaxy groups' have hardly been realised as a separate class of objects with specific characteristics in the structural hierarchy. The presumption that the self-similarity of dark matter structures is a valid prescription for the baryonic…
The Galaxy's stellar populations are naturally classified into six `types', of which five have been observed. These are the thin disk (Pop I in the historical scheme), a discrete thick disk (Pop I.5), the metal-rich bulge, which was not…
We study the detailed structure of galaxies at redshifts z > 2 using cosmological simulations with improved modeling of the interstellar medium and star formation. The simulations follow the formation and dissociation of molecular hydrogen,…
We determine the cross-correlation function between galaxies and galaxy groups, using both the Two-Degree Field Galaxy Redshift Survey (2dFGRS) and the Sloan Digital Sky Survey (SDSS). We study the cross-correlation as a function of group…
We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACSJ0025.4-1222. As was previously shown by the example of the Bullet Cluster (1E0657-56), such systems are ideal laboratories for…
To reveal the galactic dark matter in the form of MACHOs ("Massive Astrophysical Compact Halo Objects"), the POINT-AGAPE collaboration is carrying out a search for gravitational microlensing towards M31. A clear microlensing signal is…
The 11 known satellite galaxies within 250 kpc of the Milky Way lie close to a great circle on the sky. We use high resolution N-body simulations of galactic dark matter halos to test if this remarkable property can be understood within the…