Galaxy-galaxy lensing is a powerful probe of the connection between galaxies and their host dark matter halos, which important both for galaxy evolution cosmology. We extend measurement modeling galaxy-galaxy signal in recent Dark Energy Survey Year 3 cosmology analysis to highly nonlinear scales ($\sim 100$ kpc). This extension enables us study galaxy-halo via Halo Occupation Distribution (HOD...

A new method for measuring gravitational lensing with high redshift type Ia supernovae is investigated. The method utilizes correlations between foreground galaxies and supernova brightnesses to substantially reduce possible systematic errors and increase the signal to noise ratio. It is shown that this lensing signal can be related to the mass, size and substructure of galaxy halos and galaxy ...

The clustering of matter on cosmological scales is an essential probe for studying the physical origin and composition of our Universe. To date, most of the direct studies have focused on shear-shear weak lensing correlations, but it is also possible to extract the dark matter clustering by combining galaxy-clustering and galaxy-galaxy-lensing measurements. In order to extract the required info...

A new method for measuring gravitational lensing with high redshift type Ia supernovae is investigated. The method utilizes correlations between foreground galaxies and supernova brightnesses to substantially reduce possible systematic errors and increase the signal to noise ratio. It is shown that this lensing signal can be related to the mass, size and substructure of galaxy halos and galaxy ...

We present results for a galaxy formation model that includes a simple treatment for the disruption of dwarf galaxies by gravitational forces and galaxy encounters within galaxy clusters. This is implemented a posteriori in a semi–analytic model by considering the stability of cluster dark matter sub-haloes at z = 0. We assume that a galaxy whose dark matter substructure has been disrupted will...

It is of great interest to measure the properties of substructures in dark matter halos at galactic and cluster scales. Here we suggest a method to constrain substructure properties using the variance of weak gravitational flexion in a galaxy-galaxy lensing context. We show the effectiveness of flexion variance in measuring substructures in N-body simulations of dark matter halos, and present t...

A simple model is constructed to evaluate the change of star formation rate of a disk galaxy due to environmental e†ects in clusters of galaxies. Three e†ects are investigated : (1) tidal force from the potential well of the cluster, (2) increase of external pressure when the galaxy plows into the intracluster medium, and (3) high-speed encounters between galaxies. General analysis indicates th...

The Las Campanas Redshift Survey (LCRS) is a galaxy survey which extends to a red-shift of 0.2 and which is composed of a total of 6 alternating 1:5 80 Slices in the North and South Galactic Caps. Now in its nal stages, the Survey contains approximately 26,400 galaxy redshifts. We present here a deenitive LCRS galaxy-galaxy autocorrela-tion function gg (s), its comparison to the gg (s) from var...

We present the first optical observations of the radio source 4C +08.45. It is identified with an elliptical galaxy (R = 15.92) at redshift z= 0.1250, with a comparable companion galaxy (R = 15.36; z= 0.1257) at a projected distance of 34.8 kpc. Both galaxies are normal elliptical galaxies. The galaxy identified with the radio source shows strong emission lines on top of an elliptical galaxy sp...