Related papers: Quasar Metal Abundances and Host Galaxy Evolution
We determined C, N and alpha-element relative abundances in the gas surrounding six QSOs at an average redshift of < z > ~ 2.4, by studying six narrow associated absorption systems in UVES high-resolution spectra. We found five systems with…
Obscuration in quasars may arise from steep viewing angles along the dusty torus, or instead may represent a distinct phase of supermassive black hole growth. We test these scenarios by probing the host dark matter halo environments of…
Galactic bulges are central to understanding galaxy formation and evolution. Here we report on recent studies using micro-lensing events to obtain spectra of high resolution and moderately high signal-to-noise ratios of dwarf stars in the…
We are now routinely detecting gravitational waves (GW) emitted by merging black holes and neutron stars. Those are the afterlives of massive stars that formed all across the Universe - at different times and with different metallicities…
In the past decade, much effort was devoted to measure the masses of supermassive black holes in galactic nuclei, to establish the relation between black hole mass and the global/nuclear properties of the host galaxy, and to understand the…
The relation between star formation rates and stellar masses, i.e. the galaxy main sequence, is a useful diagnostic of galaxy evolution. We present the distributions relative to the main sequence of 55 optically-selected PG and 12…
Recent observations indicate a remarkable similarity in the properties of evolving galaxies at fixed mass and redshift, prompting us to consider the possibility that most galaxies may evolve with a common history encompassing star…
Quasars are the earliest objects known to exist. We examine their origin in the context of popular models for structure formation in the universe. We show that seeds for quasar black holes could have originated from the initial cosmological…
We investigate the hypothesis that quasars formed together with the stellar populations of early-type galaxies. This hypothesis, in conjunction with the stellar ages of early-type galaxies from population synthesis models, the relation of…
Quasars are among the most luminous objects in the universe, and they can be studied in detail up to the highest known redshift. Assuming that the gas associated with quasars is closely related to the interstellar medium of the host galaxy,…
High-redshift quasars are believed to reside in highly biased regions of the Universe, where black hole (BH) growth is sustained by an enhanced number of mergers and by being at the intersection of filaments bringing fresh gas. This…
Our Galaxy is a complex machine in which several processes operate simultaneously: metal-poor gas is accreted, is chemically enriched by dying stars, and then drifts inwards, surrendering its angular momentum to stars; new stars are formed…
Since their discovery the analysis of quasar magnitudes has generally required some form of evolution. Assuming that quasars do not have evolution this paper shows that they have a well-defined intrinsic magnitude distribution that is…
Massive stars play a major role in the evolution of their host galaxies, and serve as important probes of the distant Universe. It has been established that the majority of massive stars reside in close binaries and will interact with their…
The determination of chemical abundances in star-forming galaxies and the study of their evolution on cosmological timescales are powerful tools for understanding galaxy formation and evolution. This contribution presents the latest results…
We investigate how accretion episodes onto massive black holes power quasars and AGN while they accumulate mass into the holes. We compute both the trend and the stochastic component to the trigger of the accretion events, as provided by…
The existence of supermassive black holes is supported by a growing body of observations. Supermassive black holes and their formation events are likely candidates for detection by proposed long-wavelength, space-based gravitational wave…
We argue that extreme metal-poor stars show a high dispersion in metallicity, because their abundances are the outcome of very few supernova events. Abundance anomalies should appear because of the discrete range of progenitor masses. There…
Starbursts are extreme concentrations of star-forming activity with mass conversion surface densities reaching over 1000 times higher than normal for disk galaxies. They are responsible for a large fraction of all cosmic star formation.…
Since stellar populations enhance particular element abundances according to the yields and lifetimes of the stellar progenitors, the chemical evolution of galaxies serves as one of the key tools that allows the tracing of galaxy evolution.…