Related papers: Do galaxies form a spectroscopic sequence?
Clusters of galaxies outline the network of the distribution of visible matter in the Universe, marking the highest-mass knots where filamentary structures join together. If we observe the sky in X rays, clusters of galaxies stand out as…
Galaxies cover a wide range of masses and star formation histories. In this review, I summarize some of the evolutionary key features of common galaxy types. At the high-mass end, very rapid, efficient early star formation is observed,…
It is now a well established fact that galaxies undergo significant morphological transformation during their lifetimes, manifesting as an evolution along the Hubble sequence from the late to the early Hubble types. The physical processes…
Following the recent surge of interest in peculiar galaxies at high redshifts we consider the definition, or lack thereof, of morphological peculiarities on a sample of local universe galaxies. Studying the morphology of local universe…
We summarise some recent results about nearby galactic bulges that are relevant to their formation. We highlight a number of significant advances in our understanding of the surface brightness profiles, stellar populations, and especially…
This talk investigates the formation of early-type galaxies from a deliberately observational view point. I begin by reviewing the conclusions that can be reached by comparing the detailed properties of galaxies in present-day clusters,…
Each galaxy is observed only once along its life, making galaxy evolution fundamentally an inverse statistical problem: time-dependent physics must be inferred from ensembles of single-epoch snapshots. To move beyond descriptive scaling…
The present paper presents a discussion of classification systems for galaxies, with special emphasis on possible modifications of the Hubble "tuning fork" diagram, and on galaxy types not included in Hubble's original scheme. Hubble's…
Galaxy morphology is a product of how galaxies formed, how they interacted with their environment, how they were influenced by internal perturbations, AGN, and dark matter, and of their varied star formation histories. This article reviews…
The spectra of Active Galactic Nuclei (AGNs) are often characterized by a wealth of emission lines with different profiles and intensity ratios that led to a complicated classification. Their electro-magnetic radiation spans more than 10…
There is an obvious need for automated classification of galaxies, as the number of observed galaxies increases very fast. We examine several approaches to this problem, utilising {\em Artificial Neural Networks} (ANNs). We quote results…
The so-called star-forming main sequence of galaxies is the apparent tight relationship between the star formation rate and stellar mass of a galaxy. Previous studies exclude galaxies which are not strictly 'star forming' from the main…
It is well established that (1) star-forming galaxies follow a relation between their star formation rate (SFR) and stellar mass (M$_{\star}$), the "star-formation sequence", and (2) the SFRs of galaxies correlate with their structure,…
The physical mechanisms and timescales that determine the morphological signatures and the quenching of star formation of typical (~L*) elliptical galaxies are not well understood. To address this issue, we have simulated the formation of a…
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 different ways according to their morphological…
We have analyzed the emission line properties in the integrated spectra of 15 normal spiral galaxies. We show that very clear trends appear when plotting relevant emission line ratios or equivalent widths as a function of galaxy spectral…
(Abridged) We have used optical spectroscopy to investigate the radio- selected active galaxy populations in a sample of 20 nearby Abell clusters. The spectra were used to characterize the galaxies as AGN or galaxies forming stars at rates…
The distribution of global photometric, spectroscopic, structural and morphological parameters for a well defined sample of 350 nearby galaxies has been examined. The usual trends were recovered demonstrating that E/S0 galaxies are redder,…
Analysis of the deepest available images of the sky, obtained by the Hubble Space Telescope, reveals a large number of candidate high-redshift galaxies. A catalogue of 1,683 objects is presented, with estimated redshifts ranging from $z=0$…
Compact groups of galaxies have posed a number of challenging questions. Intensive observational and theoretical studies are now providing answers to many of these, and at the same time, are revealing unexpected new clues about the nature…