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This paper describes how active galactic nuclei can heat galaxy-cluster plasmas by driving convection in the intracluster medium. A model is proposed in which a central supermassive black hole accretes intracluster plasma at the Bondi rate…
Processes that promote the formation of dense cold clouds in the interstellar media of galaxies are reviewed. Those that involve background stellar mass include two-fluid instabilities, spiral density wave shocking, and bar accretion. Young…
A brief overview of recent advances in the study of star formation in the Galactic Center (GC) environment is presented. Particular attention is paid to new insights concerning the suppression of star formation in GC molecular clouds.…
In this thesis we have identified two star formation sites for star formation in galaxies which differ widely in metal content. We conclude that `massive' star formation that occurs in a high density, high metallicity environment, like that…
Galactic outflows can be powered either by nuclear starbursts (SB) or active galactic nuclei (AGN). It has been argued that extreme starbursts can power extreme outflows, without the need to invoke AGN feedback. However, contributions from…
The conversion of gas into stars is a fundamental process in astrophysics and cosmology. Stars are known to form from the gravitational collapse of dense clumps in interstellar molecular clouds, and it has been proposed that the resulting…
Most stars form in compact, dense embedded clusters with memberships ranging from a dozen stars to many millions of stars. Embedded clusters containing more than a few hundred stars also contain O stars that disrupt the nebula abruptly.…
I discuss the observational evidence that starburst galaxies are able to drive galactic-scale outflows ("superwinds") and then argue generally that superwinds must have had an important role in galaxy evolution. To explore the role of…
The Universe's largest galaxy clusters likely built the majority of their massive $>10^{11} M_\odot$ galaxies in simultaneous, short-lived bursts of activity well before virialization. This conclusion is reached from emerging datasets on…
The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the…
High resolution X-ray spectroscopy of the hot gas in galaxy clusters has shown that the gas is not cooling to low temperatures at the predicted rates of hundreds to thousands of solar masses per year. X-ray images have revealed giant…
We present the star formation rate (SFR) measurements based on the spectral energy distribution (SED) analysis with new sub-mm fluxes combined with archival multi-wavelength data for a sample of 52 AGN host galaxies at z $<0.2$. We carried…
We extract from the Sloan Digital Sky Survey a sample of 347 systems involving early type galaxies separated by less than 30 kpc, in projection, and 500 km/s in radial velocity. These close pairs are likely progenitors of dry mergers. The…
Galactic nuclei often harbor a disproportionately large amount of star formation activity with respect to their surrounding disks. Not coincidentally, the density of molecular material in galactic nuclei is often also much greater than that…
We show that the luminosity of a star forming galaxy is capped by the production and subsequent expulsion of cosmic rays from its interstellar medium. By defining an Eddington luminosity in cosmic rays, we show that the star formation rate…
NGC 253 hosts the nearest nuclear starburst. Previous observations show a region rich in molecular gas, with dense clouds associated with recent star formation. We used ALMA to image the 350 GHz dust continuum and molecular line emission…
Large-scale outflows driven by supermassive black holes are thought to play a fundamental role in suppressing star formation in massive galaxies. However, direct observational evidence for this hypothesis is still lacking, particularly in…
Observations have suggested that galactic outflows contain substantial amounts of dense and clumpy molecular gas, creating favourable conditions for igniting star formation. Indeed, theoretical models and hydrodynamical simulations have…
We present infrared luminosities, star formation rates, colors, morphologies, locations, and AGN properties of 24 micron-detected sources in photometrically detected high-redshift clusters in order to understand the impact of environment on…
We investigate the interactions of high-redshift galaxy outflows with low-mass virialized (Tvir < 10,000K) clouds of primordial composition. While atomic cooling allows star formation in larger primordial objects, such "minihalos" are…