The simple unification scheme of powerful radio galaxies and quasars, based entirely on the orientation dependent effects, has been confronted with the observed radio structures for 152 radio galaxies and 173 steep spectrum quasars. Contrary to the scheme's prediction, the cosmological evolution of geometrical parameters describing the large scale structure of these two types of radio sources a...

We quantify the angular distribution of radio sources in the NVSS by measuring the two-point angular correlation function w(θ). By careful consideration of the resolution of radio galaxies into multiple components, we are able to determine both the galaxy angular clustering and the size distribution of giant radio galaxies. The slope of the correlation function for radio galaxies agrees with th...

We present a first morphological study of z ∼ 7 − 8 Lyman Break galaxies (LBGs) from Oesch et al. (2009b) and Bouwens et al. (2009a) detected in ultra-deep near-infrared imaging of the Hubble Ultra Deep field (HUDF) by the HUDF09 program. With an average intrinsic size of 0.7 ± 0.3 kpc these galaxies are found to be extremely compact having an average observed surface brightness of µ J ≃ 26 mag...

Using the TNG100 (100 Mpc)^3 simulation of IllustrisTNG project, we demonstrate a strong connection between onset star formation quenching and stellar size galaxies. We do so by tracking evolutionary history extended normal-size galaxies selected at z=2 with log(M_star) = 10.2 - 11 stellar-half-mass-radii above within 1-sigma size--stellar mass relation, respectively. match rate distributions t...

We report here on a sample of resolved, infrared images of galaxies at z∼0.5 taken with the 10-m Keck Telescope’s Adaptive Optics (AO) system. We regularly achieve a spatial resolution of 0.05 and are thus able to resolve both the disk and bulge components. We have extracted morphological information for ten galaxies and compared their properties to those of a local sample. The selection effect...

A new sample of very large angular size radio sources has been selected from the 1.4 GHz VLA surveys: FIRST and NVSS. This sample will be very useful for an observational constraint on the time evolution of double radio sources, especially their size, predicted by numerous analytical models of such evolution (cf. Introduction). In this paper we present radio and optical data for a large fractio...

We present results on the size evolution of passively evolving galaxies at 1 . z . 2 drawn from the Wide Field Camera 3 Early Release Science program. Our sample was constructed using an analog to the passive BzK selection criterion, which isolates galaxies with little or no on-going star formation at z & 1.5. We identify 30 galaxies in ∼ 40 arcmin to H < 25 mag. We supplement spectroscopic red...

We test whether there is a relation between the observed tidal interactions and Seyfert activity by imaging in HI twenty inactive galaxies at the same spatial resolution and detection threshold as the Seyfert sample. This control sample of inactive galaxies were closely matched in Hubble type, range in size and inclination, and have roughly comparable galaxy optical luminosity to the Seyfert ga...