Related papers: Warm gas accretion onto the Galaxy
Ongoing accretion of low-metallicity gas onto the disk is a natural prediction of semi-analytical Galactic chemical evolution models. This star formation fuel ameliorates the overproduction of metal-poor G- and K-dwarfs in the solar…
We present two sets of grid-based hydrodynamical simulations of high-velocity clouds (HVCs) traveling through the diffuse, hot Galactic halo. These HI clouds have been suggested to provide fuel for ongoing star formation in the Galactic…
Many galaxy clusters pose a "cooling-flow problem", where the observed X-ray emission from their cores is not accompanied by enough cold gas or star formation. A continuous energy source is required to balance the cooling rate over the…
We investigate the convective stability of two popular types of model of the gas distribution in the hot Galactic halo. We first consider models in which the halo density and temperature decrease exponentially with height above the disk.…
We continue our empirical study of the emission line flux originating in the cool ($T\sim10^4$ K) gas that populates the halos of galaxies and their environments. Specifically, we present results obtained for a sample of nearly half a…
We have discovered a remarkable warm (130-160 K) molecular hydrogen tail with a H_2 mass of approximately 4*10^7 solar masses extending 20 kpc from a cluster spiral galaxy, ESO 137-001, in Abell 3627. At least half of this gas is lost…
A recent re-analysis of EGRET data by Dixon et al. has led to the discovery of a statistically significant diffuse $\gamma$-ray emission from the galactic halo. We show that this emission can naturally be accounted for within a…
Evidence for the accretion of material in spiral galaxies has grown over the past years and clear signatures can be found in HI observations of galaxies. We describe here new detailed and sensitive HI synthesis observations of a few nearby…
Searching the HI Parkes All-Sky Survey (HIPASS) and its northern extension, we detected a population of very compact high-velocity clouds (HVCs) with similar velocities in the Galactic standard-of-rest frame which appear to be arranged in…
We report the first evidence of molecular gas in two atomic hydrogen (HI) clouds associated with gas outflowing from the Small Magellanic Cloud (SMC). We used the Atacama Pathfinder Experiment (APEX) to detect and spatially resolve…
Hot ionized gas is important in the baryon cycle of galaxies and contributes the majority of their ``missing baryons''. Until now, most semi-analytic models of galaxy formation have paid little attention to hot gaseous haloes and their…
Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless…
Understanding the survival, growth and dynamics of cold gas is fundamental to galaxy formation. While there has been a plethora of work on `wind tunnel' simulations that study such cold gas in winds, the infall of this gas under gravity is…
Cold-mode gas accretion onto galaxies is a direct prediction of LCDM simulations and provides galaxies with fuel that allows them to continue to form stars over the lifetime of the Universe. Given its dramatic influence on a galaxy's gas…
In addition to the hot intracluster medium, massive galaxy clusters host complex, multi-phase gaseous halos. In this work, we quantify the abundance, spatial distribution, and origin of the cool T < 10^4.5 K gas within clusters. To do so,…
In previous studies, it has been shown that the large line widths observed in high surface brightness H-alpha emitters at low and high redshifts are likely due to the mechanical energy injected by intense star formation. Here we discuss the…
We study the properties of gas inside and around galaxy haloes as a function of radius and halo mass, focussing mostly on z=2, but also showing some results for z=0. For this purpose, we use a suite of large cosmological, hydrodynamical…
Within protogalaxies, thermal instability leads to the formation of a population of cool fragments, confined by the pressure of residual hot gas. The hot gas remains in quasi-hydrostatic equilibrium, at approximately the virial temperature…
Using X-ray constrained beta-models for the radial distribution of gas in the outskirts of galaxies, we analyze the termination of galactic winds and the formation and evolution of halo clouds by thermal instability. At low mass-loss rates,…
The Milky Way is acquiring gas from infalling high-velocity clouds. The material enters a disk-halo interface that in many places is populated with HI clouds that have been ejected from the disk through processes linked to star formation.…