Related papers: Metagalactic Ultraviolet Flux from Cosmic Structur…
The preheating of intergalactic medium(IGM) by structure collapsing and ultraviolet background(UVB) are investigated in cosmological hydrodynamical simulations. When gravitational collapsing is the sole heating mechanism, we find that (1)…
The possibility of detecting proto-galaxies in the UV band is pointed out, assuming that galaxy formation occured at z $\sim 5-6$. It is shown that the diffuse gas in collapsing galaxy sized objects with temperatures $\sim 10^{6\pm0.5}$ K,…
We present a new theoretical calculation of the contribution to the extragalactic gamma-ray background radiation (EGRB) from star-forming galaxies, based on a state-of-the-art model of hierarchical galaxy formation that is in quantitative…
The effect of the cosmic UV background on star formation in high redshift galaxies is explored by means of high resolutions cosmological simulations. The simulations include star formation, 3D radiative transfer, and a highly detailed ISM…
In hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (T_vir < 10^4 K) halos that collapse before reionization. The UVB at energies below 13.6eV suppresses the formation of stars or…
We derive apparent and absolute ultraviolet (UV) magnitudes, and luminosities in the infrared (IR) range of a large sample of low-redshift (0<z<1) compact star-forming galaxies (CSFGs) selected from the Data Release 12 of the Sloan Digital…
We present the first results of an ongoing spectroscopic survey of galaxies selected in the rest-frame ultraviolet. The source catalogue was constructed from a flux-limited sample of stars, galaxies and QSOs imaged at 2000 \AA with the FOCA…
We present hydrodynamical simulations of the formation of galaxies in the mass range 10^9 - 10^13 solar masses, with the focus on the efficiency of gas cooling. The effect of a background UV radiation field, and the effect of metal…
In this paper, we report on a first estimate of the contribution of galaxies to the diffuse extragalactic background from the far-UV to the submm, based on semi--analytic models of galaxy formation and evolution. We conclude that the global…
The reionization of cosmic hydrogen, left over from the big bang, increased its temperature to >~ 1.e4 K. This photo-heating resulted in an increase of the minimum mass of galaxies and hence a suppression of the cosmic star formation rate.…
The cosmic thermal history, quantified by the evolution of the mean thermal energy density in the universe, is driven by the growth of structures as baryons get shock heated in collapsing dark matter halos. This process can be probed by…
We study the observed cosmic ionizing background as a constraint on the nature of the sources responsible for the reionization of the Universe. In earlier work, we showed that extrapolations of the Ultra-Violet Luminosity Function (LF) of…
The cosmic ultraviolet (UV) ionizing background impacts the formation of dwarf galaxies in the low-redshift universe (z=3) by suppressing gas infall into galactic halos with circular velocities up to v(circ)=75 km/s. Using a…
Early results from the JWST observations have reported a surprisingly high number of UV-bright galaxies at $z \geq 10$, which appears to challenge the theoretical predictions from standard galaxy formation models in the $\Lambda$CDM…
We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. A "minimal cosmic reionization model" is presented in which the galaxy UV emissivity traces…
A field with particularly exciting results over the past few years is the study of the interaction of cosmic rays with interstellar matter. For star formation to take place, gas and dust need to be sufficiently cold for gravity to overcome…
Using 3D radiative transfer calculations on the reionization of an inhomogeneous universe, QSO absorption line systems are simulated and they are compared with observations of Ly$\alpha$ continuum depression at high redshifts. By this…
In nuclei of starburst galaxies, the combination of an enhanced rate of supernova explosions and a high gas density suggests that cosmic rays can be efficiently produced, and that most of them lose their energy before escaping these…
There has been remarkable progress recently in both observational and theoretical studies of galaxy formation and evolution. Largely due to a combination of deep Hubble Space Telescope imaging, Keck spectroscopy, and COBE far-IR background…
I use a 1-D Lagrangian code which follows both a gaseous and a dark component to study the effects of a metagalactic UV background on the formation of dwarf galaxies. In the case of an ionising background consistent with the existing…