Related papers: On the origin of the galaxy luminosity function
The properties of old globular cluster systems in galaxy halos are used to infer quantitative constraints on aspects of generic star (cluster) formation. First, the spatial distribution of globulars in three large galaxies, together with…
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
Stars form by gravoturbulent fragmentation of interstellar gas clouds. The supersonic turbulence ubiquitously observed in Galactic molecular gas generates strong density fluctuations with gravity taking over in the densest and most massive…
We report new observations of circumgalactic gas in the halos of early type galaxies obtained by the COS-Halos Survey with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope. We find that detections of HI surrounding early…
The current generation of millimeter interferometers have revealed a population of compact (r <~ 0.1 pc), massive (M ~ 100 Msun) gas cores that are the likely progenitors of massive stars. I review models for the evolution of these objects…
We investigate phenomenological models of star formation and supernova feedback in N-body/SPH simulations of galaxy formation. First, we compare different prescriptions in the literature for turning cold gas into stars neglecting feedback…
On galactic scales, the surface density of star formation appears to be well correlated with the surface density of molecular gas. This has lead many authors to suggest that there exists a causal relationship between the chemical state of…
Massive galaxies, such as nearby ellipticals, have relatively low number densities, yet they host the majority of the stellar mass in the universe. Understanding their origin is a central problem of galaxy formation. Age dating of stellar…
High redshift quasars emit copious X-ray photons which heat the intergalactic medium to temperatures up to $\sim$ 10$^6$ K. At such high temperatures the primordial gas will not form stars until it is assembled into dark matter haloes with…
The first galaxies contain stars born out of gas with little or no metals. The lack of metals is expected to inhibit efficient gas cooling and star formation but this effect has yet to be observed in galaxies with oxygen abundance relative…
We show that the gas mass fraction of spiral galaxies is strongly correlated with luminosity and surface brightness. It is not correlated with linear size. Gas fraction varies with luminosity and surface brightness at the same rate,…
Motivated by the recently improved knowledge on the kinematic and chemical properties of the Galactic metal-poor stars, we present the numerical simulation for the formation of the Galactic stellar halo to interpret the observational…
The star formation rate in galaxies should be related to the fraction of gas that can attain densities large enough for gravitational collapse. In galaxies with a turbulent interstellar medium, this fraction is controlled by the effective…
We show that the gas in growing density perturbations is vulnerable to the influence of winds outflowing from nearby collapsed galaxies that have already formed stars. This suggests that the formation of nearby galaxies with masses less…
The conditions for structure formation which ultimately lead to galaxies request further ingredients behind the simple collapse criteria. The Jean's criteria and the cooling criteria are those which are currently used. However in such a…
X-ray emission from hot (T = 10^7 K) interstellar gas in massive elliptical galaxies indicates that 10^{10} M_sun has cooled over a Hubble time, but optical and radio evidence for this cold gas is lacking. We provide detailed theoretical…
We consider the possibility that the dark matter in the halos of galaxies may be in the form of clusters of \macho s within which are embedded cold, dense gas clouds. Microlensing experiments have found evidence that the Galactic halo…
We use a series of N-body/smoothed particle hydrodynamics simulations and analytic arguments to show that the presence of an effective temperature floor in the interstellar medium at T_F ~ 10^4 K naturally explains the tendency for low-mass…
We present a revised and extended version of the analytic model for cosmic star formation originally given by Hernquist & Springel in 2003. The key assumption of this formalism is that star formation proceeds from cold gas, at a rate that…
Starlight from galaxies plays a pivotal role throughout the process of cosmic reionisation. We present the statistics of dwarf galaxy properties at z > 7 in haloes with masses up to 10^9 solar masses, using a cosmological radiation…