Related papers: QSO Absorption Lines, Gaseous Infall and Star Form…
Intrinsic emission and absorption lines of QSOs provide several independent probes of the metal abundances in QSO environments. They indicate that the metallicities are typically solar or higher out to redshifts z > 4. These results support…
Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most…
The formation of galactic discs and the efficiency of star formation within them are issues central to our understanding of galaxy formation. We have developed a detailed and versatile model of disc formation which combines the strengths of…
The effects of wind-driven star formation feedback on the spatio-temporal organization of stars and gas in galaxies is studied using two-dimensional intermediate-representational quasi-hydrodynamical simulations. The model retains only a…
Quantification of the Galaxy's star formation history involves both the duration and the rate of formation, with these parameters being known with different precision for different populations. The early rate of star formation is knowable…
We use a gaseous model and a semi-analytical approach to study the evolution of a super-massive central gaseous object (a super-massive star, (SMS from now on) in an AGN and its evolution by interactions with the surrounding stellar system.…
We report the first results of a detailed study of the star formation law in a sample of 32 nearby spiral galaxies with well-measured rotation curves, HI and H$_2$ (as traced by CO) surface density profiles, and new \Ha CCD photometry. Our…
A review of gravitational and hydrodynamical processes during formation of clusters and evolution of galaxies is given. Early, at the advent of N-body computer simulations, the importance of tidal fields in galaxy encounters has been…
Using the star formation rates from the SDSS galaxy sample, extracted using the MOPED algorithm, and the empirical Kennicutt law relating star formation rate to gas density, we calculate the time evolution of the gas fraction as a function…
In the present universe, the gas is a minor component of giant galaxies, and its dominant phase is atomic (HI). During galaxy evolution in cosmic times, models predict that gas fractions were much higher in galaxies, and gas phases could be…
A clear understanding of the chemical processing of matter, as it is transferred from a molecular cloud to a planetary system, depends heavily on knowledge of the physical conditions endured by gas and dust as these accrete onto a disk and…
The cluster environment is the site of important transformations in galaxies at a relatively recent cosmological epoch: the galactic morphological types and star formation activity have evolved significantly during the last few Gyrs. How is…
Numerous observations indicate that galaxies need a continuous gas supply to fuel star formation and explain the star formation history. However, direct observational evidence of gas accretion remains rare. Using the EAGLE cosmological…
After a brief introduction to gravitational lensing theory, a rough overview of the types of gravitational lensing statistics that have been performed so far will be given. I shall then concentrate on recent results of galaxy-galaxy…
Absorption signatures in the spectra of QSOs are one of our most powerful tools for studying galactic and intergalactic environments at high redshifts. With the discovery of QSOs out to z > 7, QSO absorption lines are now tracing the end…
Dynamical evolution of spiral galaxies is strongly dependent on non-axisymmetric patterns that develop from gravitational instabilities, either spontaneously or externally triggered. Some evolutionary sequences are described through which a…
We study the response of the gaseous component of a galactic disc to the time dependent potential generated by N-body simulations of a spiral galaxy. The results show significant variation of the spiral structure of the gas which might be…
We present results from an ongoing search for galaxy counterparts of a subgroup of Quasar Absorption Line Systems called Damped Ly-alpha Absorbers (DLAs). DLAs have several characteristics that make them essential in the process of…
The last 20 years have seen an explosion in our understanding of the large-scale distribution and motions of galaxies in the nearby universe. The field has moved from a largely qualitative, morphological description of the structures seen…
Since the 1990's, protoplanetary disks and planetary disks have been intensively observed from the optical to the millimetre wavelength and many models have been developed to investigate their gas and dust properties and dynamics. These…