We use the exceptional depth of the Ultra Deep Field (UDF) and UDFParallel ACS fields to study the sizes of high redshift (z ∼ 2 − 6) galaxies and address long-standing questions about possible biases in the cosmic star formation rate due to surface brightness dimming. Contrasting B, V , and i-dropout samples culled from the deeper data with those obtained from the shallower GOODS fields, we de...

We report a discovery of extended counterrotating gaseous disks in early-type disk galaxies NGC 2551 and NGC 5631. To find them, we have undertaken complex spectral observations including integralfield spectroscopy for the central parts of the galaxies and long-slit deep spectroscopy to probe the external parts. The line-of-sight velocity fields have been constructed and compared to the photome...

We discuss CSS radio galaxies from 2 samples of radio sources. The rst sample is a complete sample of 28 3CR galaxies with redshifts in the range 0:6 < z < 1:8 for which we have HST, UKIRT and VLA imaging data. The 2 CSS galaxies contained in this sample, 3C49 and 3C241, appear to be less active than galaxies with radio sizes of order 50{100 kpc, but similar in activity to galaxies with radio s...

We present the star formation histories, luminosities, colors, mass to light ratios, and halo masses of ”galaxies” formed in a simulation of cosmological reionization. We compare these galaxies with Lyman Break Galaxies observed at high redshift. While the simulation is severely limited by the small box size, the simulated galaxies do appear as fainter cousins of the observed ones. They have si...

A detailed analysis of the galaxy distribution in the Southern Sky Redshift Survey (SSRS) by means of the multifractal or scaling formalism is presented. It is shown that galaxies cluster in di erent ways according to their morphological type as well as their size. Ellipticals are more clustered than spirals, even at scales up to 15 h 1 Mpc, whereas no clear segregation between early and late s...

Traditionally globular clusters and dwarf spheroidal galaxies have been distinguished by using one or more of the following criteria: (1) mass, (2) luminosity, (3) size, (4) mass-to-light ratio and (5) spread in metallicity. However, a few recently discovered objects show some overlap between the domains in parameter space that are occupied by galaxies and clusters. In the present note it is sh...

We examine volume-limited samples of galaxies drawn from the Sloan Digital Sky Survey to look for relations among internal and collective physical parameters of galaxies as faint as Mr = −17.5. The internal physical properties of interest include morphology, luminosity, color, color gradient, concentration, size, velocity dispersion, equivalent width of Hα line, and axis ratio. Collective prope...

E+A galaxies have been interpreted as post-starburst galaxies based on the presence of strong Balmer absorption lines combined with the absence of major emission lines ([OII] nor Hα). As a population of galaxies in the midst of the transformation, E+A galaxies has been subject to an intense research activity. It has been, however, difficult to investigate E+A galaxies statistically since E+A ga...

Because of the contamination of jets, using the size – continuum luminosity relation can overestimate the broad line region (BLR) size and black hole mass for radio-loud AGNs. We propose a new relation between the BLR size and Hβ emission line luminosity and present evidences for using it to get more accurate black hole masses of radio-loud AGNs. For extreme radio-loud AGNs such as blazars with...