Stellar photometry of nearby irregular galaxies of the Local Group is used to identify and study the young and old stellar populations of these galaxies. An analysis of the spatial distributions of stars of different ages in face-on galaxies shows that the young stellar populations in irregular galaxies are concentrated toward the center, and form local inhomogeneities in star-forming regions, ...

The luminosity dependence of kinematical and isophotal properties of elliptical galaxies is investigated using numerical simulations of galaxy merging, combined with semi-analytical models of hierarchical structure formation. Mergers of spiral galaxies as the only formation mechanism for elliptical galaxies can neither reproduce the kinematical and photometric properties of very massive ellipti...

With the aid of a simple yet robust approach we investigate the influence of dissipationless and dissipative merging on galaxy structure, and the consequent effects on the scaling laws followed by elliptical galaxies. Our results suggest that ellipticals cannot be originated by parabolic merging of low mass spheroids only, even in presence of substantial gas dissipation. However, we also found ...

We present new results on the clustering and three-dimensional distribution of radio galaxies from the Texas-Oxford NVSS Structure (TONS) survey. The TONS survey was constructed to look at the distribution of radio galaxies in a region of moderate (0 ∼ z < ∼ 0.5) redshifts by matching NVSS sources with objects in APM catalogues to obtain a sample of optically bright (R ≤ 19.5), radio faint (1.4...

We analyse new SCUBA-2 submillimeter and archival SPIRE far-infrared imaging of a z =1.62 cluster, Cl 0218.3−0510, which lies in the UKIDSS/UDS field of the SCUBA-2 Cosmology Legacy Survey. Combining these tracers of obscured star formation activity with the extensive photometric and spectroscopic information available for this field, we identify 31 far-infrared/submillimeter-detected probable ...

We have conducted a systematic search for stellar disk truncations in disk–like galaxies at intermediate redshift (z<1.1) using the Hubble Ultra Deep Field (UDF) data. We use the position of the truncation as a direct estimator of the size of the stellar disk. After accounting for the surface brightness evolution of the galaxies, our results suggest that the radial position of the truncations h...

We have observed 60 edge-on galaxies in the NIR in order to study the stellar distribution in galaxies with box/peanut-shaped bulges. The much smaller amount of dust extinction at these wavelengths allows us to identify in almost all target galaxies with box/peanut-shaped bulges an additional thin, central component in cuts parallel to the major axis. This structure can be identified with a bar...

We present a new accurate measurement of the H I mass function of galaxies from the HIPASS Bright Galaxy Catalog, a sample of 1000 galaxies with the highest H I peak flux densities in the southern (δ < 0) hemisphere (Koribalski et al. 2003). This sample spans nearly four orders of magnitude in H I mass (from log(MHI⁄ M⊙) + 2logh75 = 6.8 to 10.6) and is the largest sample of H I selected galaxie...

We present evidence for a significant overdensity of red galaxies, as much as a factor of 14 over comparable field samples, in the field of the z = 1.47 radio galaxy B3 0003+387. The colors and luminosities of the brightest red galaxies are consistent with their being at z > 0.8. The radio galaxy and one of the red galaxies are separated by 5 and show some evidence of a possible interaction. Ho...

The Nuker law was designed to match the inner few (∼3-10) arcseconds of predominantly nearby (. 30 Mpc) early-type galaxy light-profiles; it was never intended to describe an entire profile. The Sérsic model, on the other hand, was developed to fit the entire profile; however, due to the presence of partially depleted galaxy cores the Sérsic model cannot always describe the very inner region. W...