Related papers: LYMAN $\alpha$ FORESTS AND COOLING OUTFLOW FROM DW…
We consider the impact of quasar outflows on structure formation. Such outflows are potentially more important than galactic winds, which appear insufficient to produce the level of preheating inferred from X-ray observations of galaxy…
We use hydrodynamic simulations to predict correlations between Lya forest absorption and galaxies at redshift z~3. The probability distribution function (PDF) of Lya flux decrements shifts systematically towards higher values in the…
Recent detections of Lyman alpha (Ly$\alpha$) emission from $z>7.5$ galaxies were somewhat unexpected given a dearth of previous non-detections in this era when the intergalactic medium (IGM) is still highly neutral. But these detections…
We present intermediate resolution ($\sim3$ \AA ) spectra of the Ly$\alpha$ emission from 15 high redshift radio galaxies ($z>2$). Together with previously published spectra we analyze data for a sample of 18 objects. In 11 of the 18 radio…
We present deep optical spectroscopy of an extended Ly$\alpha$ emission-line blob located in an over-dense region at redshift $z \approx 3.1$; `blob 1' of Steidel et al. (2000). The origin of such Ly$\alpha$ blobs has been debated for some…
By exploiting small-scale structure formation probed by Lyman-$\alpha$ forest observations, we study constraints on a model of dark matter from dark sector decay. We compute the phase space distribution of the dark matter and the linear…
We study the clustering of matter in the intergalactic medium from the Lyman-alpha forests seen in the spectra of pairs or groups of z ~ 2 quasars observed with FORS2 and UVES at the VLT-UT2 Kueyen ESO telescope. The sample consists of five…
We present semi-analytic models of galactic outflows, constrained by available observations on high redshift star formation and reionization. Galactic outflows are modeled in a manner akin to models of stellar wind blown bubbles. Large…
We discuss the effects of gravitational collapse on the shape of absorption line profiles for low column density (log N(HI) < 14) Lyman Alpha forest clouds and argue by comparison with cosmological simulations that Lyman alpha forest…
Lyman-alpha (Ly{\alpha}) photons from ionizing sources and cooling radiation undergo a complex resonant scattering process that generates unique spectral signatures in high-redshift galaxies. We present a detailed Ly{\alpha} radiative…
Recent results have shown that a substantial fraction of high-redshift Lyman alpha galaxies contain considerable amounts of dust. This implies that Lyman alpha galaxies are not primordial, as has been thought in the past. However, this dust…
The local power law relationship between the surface densities of neutral hydrogen gas and star formation rate (SFR) can be used to explore the SFR properties of damped Lyman alpha (DLA) systems at higher redshift. We find that while the…
The optical filaments found in many cooling flows in galaxy clusters consist of low density ($\sim 10^3 \pcc$) cool ($\sim 10^3$ K) gas surrounded by significant amounts of cosmic-ray and magnetic-field energy. Their spectra show…
Lyman-alpha is now widely used to investigate the galaxy formation and evolution in the high redshift universe. However, without a rigorous understanding of the processes which regulate the Lya escape fraction, physical interpretations of…
Theoretical and observational arguments suggest that the intergalactic medium (IGM) might have been polluted with metals produced by early star formation. In this scenario, Lyman-break galaxies (LBGs) at redshift z=3 are likely to be…
In order to interpret H2 (molecular hydrogen) quasar absorption line observations of damped Ly-alpha systems (DLAs) and sub-DLAs, we model their H2 abundance as a function of dust-to-gas ratio, including H2 self-shielding and dust…
We use cosmological hydrodynamic simulations with stellar feedback from the FIRE project to study the physical nature of Lyman limit systems (LLSs) at z<1. At these low redshifts, LLSs are closely associated with dense gas structures…
Feedback from massive stars plays a critical role in the evolution of the Universe by driving powerful outflows from galaxies that enrich the intergalactic medium and regulate star formation. An important source of outflows may be the most…
Ly$\alpha$ forests are usually associated with intergalactic gas clouds intercepting the quasar sight--line. Using as an example the Ly$\alpha$ forest of QSO 0055--26 ($z_{em} = 3.66$), we show that the probability of observing a line at…
Lyman continuum and line emission are thought to be important agents in the reionization of the early universe. Haro 11 is a rare example of a local galaxy in which Ly$\alpha$ and continuum emission have escaped without being absorbed or…