Related papers: Lyman-alpha Cooling Emission from Galaxy Formation
We investigate the large-scale structure of Lyman-alpha emission intensity in the Universe at redshifts z=2-3.5 using cross-correlation techniques. Our Lya emission samples are spectra of BOSS Luminous Red Galaxies from Data Release 12 with…
We investigate the evolution and the statistical properties of the Lya absorbers of the intergalactic medium (IGM) in the largely unexplored redshift range z=0.5-1.9. We use high-resolution (R > 30,000) UV (STIS) and optical (VLT/UVES and…
We investigate accretion disc models for the X-ray emission of Seyfert-1 galaxies and the hard state of black-hole X-ray binaries. We concentrate on two hot accretion disc models: advection-dominated accretion flow (ADAF) and recently found…
The present structure of galaxies is governed by the radiative dissipation of the gravitational and supernova energy injected during formation. A crucial aspect of this process is whether the gas cools as fast as it falls into the…
We present a pair of high-resolution smoothed particle hydrodynamics (SPH) simulations that explore the evolution and cooling behavior of hot gas around Milky-Way size galaxies. The simulations contain the same total baryonic mass and are…
We investigate the formation of the H I Lyman-alpha and Lyman-beta lines in an equatorial coronal streamer. Particular attention is paid to frequency redistribution for the scattering of the incident radiation. The properties of the…
The first galaxies in the Universe are built up where cold dark matter (CDM) forms large scale filamentary structure. Although the galaxies are expected to emit numerous Lya photons, they are surrounded by plentiful neutral hydrogen with a…
In the absence of supplementary heat, the radiative cooling of halo gas around massive galaxies (Milky Way mass and above) leads to an excess of cold gas or stars beyond observed levels. AGN jet-induced heating is likely essential, but the…
Recent XRISM observations suggest that gas mixing induced by sloshing contributes to core heating. We systematically investigate the suppression of cooling flows in galaxy cluster cool cores through three-dimensional hydrodynamic…
We present a simple physical model for populating dark matter halos with Lyman Alpha Emiiters(LAEs) and predict the physical properties of LAEs at z~3-7. The central tenet of this model is that the Ly-alpha luminosity is proportional to the…
Numerous cosmological simulations have been performed to study the formation of the first objects. We present the results of high resolution 3-D cosmological simulations of primordial objects formation using the adaptive mesh refinement…
We present the results of a Lya profile analysis of 12 Lya emitters (LAEs) at z = 2.2 with high-resolution Lya spectra. We find that all 12 objects have a Lya profile with the main peak redward of the systemic redshift defined by nebular…
We present the results of a 400ks Chandra survey of 29 extended Ly-alpha emitting nebulae (Ly-alpha Blobs, LABs) in the z=3.09 proto-cluster in the SSA22 field. We detect luminous X-ray counterparts in five LABs, implying a large fraction…
Conduction may play an important role in reducing cooling flows in galaxy clusters. We analyse a sample of sixteen objects using Chandra data and find that a balance between conduction and cooling can exist in the hotter clusters (T > 5…
We use the best available X-ray data from the intermediate polar EX Hydrae to study the cooling-flow model often applied to interpret the X-ray spectra of these accreting magnetic white dwarf binaries. First, we resolve a long-standing…
The large cross-section of the Lyman alpha (Lya) line makes it a sensitive probe of the ionization state of the intergalactic medium (IGM). Here we present the most complete study to date of the IGM Lya opacity, and its application to the…
We present far-UV HST/COS spectra of four nearby BL Lac Objects. BL Lac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or…
We use hydrodynamic cosmological simulations to study damped Lyman-alpha (DLA) and Lyman limit (LL) absorption at redshifts z=2-4 in five variants of the cold dark matter scenario. Our standard simulations resolve the formation of dense…
We revisit the question of 'hot mode' versus 'cold mode' accretion onto galaxies using steady-state cooling flow solutions and idealized 3D hydrodynamic simulations. We demonstrate that for the hot accretion mode to exist, the cooling time…
Recent stacked ALMA observations have revealed that normal, star-forming galaxies at $z\approx 6$ are surrounded by extended ($\approx 10\,\mathrm{kpc}$) [CII] emitting halos which are not predicted by the most advanced, zoom-in…