We explore the dependence of the ratio of a galaxy’s circular velocity, Vc, to its central velocity dispersion, σ0, on morphology, or equivalently light concentration, for rotationally and pressure supported galaxies. Such a dependence is expected if light traces the mass. Over the full range of galaxy types, masses and brightnesses, and assuming that the gas velocity traces the circular veloci...

Although at least one quarter of early-type barred galaxies host secondary stellar bars embedded in their large-scale primary counterparts, the dynamics of such double barred galaxies are still not well understood. Recently we reported success at simulating such systems in a repeatable way in collisionless systems. In order to further our understanding of double-barred galaxies, here we charact...

Outbursts from active galactic nuclei (AGN) affect the hot atmospheres of isolated giant elliptical galaxies (gE’s), as well as those in groups and clusters of galaxies. Chandra observations of a sample of nearby gE’s show that the average power of AGN outbursts is sufficient to stop their hot atmospheres from cooling and forming stars, consistent with radio mode feedback models. The outbursts ...

One of the most obvious facts about galaxies is that they come in a variety of sizes and luminosities. Perhaps more surprisingly is that, for a given size and luminosity, there are usually a number of different types. Remarkably, the inherent reason for this variety is still not well understood. It is one of the key requirements for a successful theory: that we can reproduce the rich diversity ...

The huge size and uniformity of the Sloan Digital Sky Survey (SDSS) make possible an exacting test of current models of galaxy formation. We compare the predictions of the GALFORM semi-analytical galaxy formation model for the luminosities, morphologies, colours and scalelengths of local galaxies. GALFORM models the luminosity and size of the disc and bulge components of a galaxy, and so we can...

A new sample of northern isolated galaxies, which are defined by the physical criterion that they were not affected by other galaxies in their evolution during the last few Gyr, is presented. To find them we used the logarithmic ratio, f , between inner and tidal forces acting upon the candidate galaxy by a possible perturber. The analysis of the distribution of the f-values for the galaxies in...

In this third of a series of papers concerning active galaxies in the FIRST and Sloan Digital Sky Surveys, we analyze the spectroscopic and radio properties of a sample of narrow-line Active Galactic Nuclei (AGN), broad-line Seyfert I galaxies, and Quasars in the local universe in order to investigate the dependence of their activity on the mass, spin and accretion rates of the supermassive bla...

We report first results from a multiwavelength campaign to measure the simultaneous spectrum of Sgr A* from cm to mm wavelengths. The observations confirm that the previously detected submm-excess is not due to variability; the presence of an ultracompact component with a size of a few Schwarzschild radii is inferred. In a VLA survey of LINER galaxies, we found Sgr A*-like nuclei in one quarter...

We reanalyze the formation and evolution of galaxies in the hierarchical clustering scenario. Using a semianalytic model (SAM) of galaxy formation described in this paper, which we hereafter call the Mitaka model, we extensively investigate the observed scaling relations of galaxies among photometric, kinematic, structural and chemical characteristics. In such a scenario, spheroidal galaxies ar...

We present high resolution radio observations of the nuclear radio emission in a sample of eight radio galaxies having Megaparsec sizes, using the European VLBI network at 18 cm. At a resolution of 25 mas we detect all the giant radio galaxies from our sample. Among themDA 240 and 1331−099 were imaged for an extended period. These observations reveal a twin-jet structure for DA 240 and one-side...