Related papers: The Temperature-Density Relation in the Intergalac…
A new determination of the temperature of the intergalactic medium over $3.9 \leq z \leq 4.3$ is presented. We applied the curvature method on a sample of 10 high resolution quasar spectra from the Ultraviolet and Visual Echelle…
We explore the intergalactic medium (IGM) as a potential source of the unresolved soft X-ray background (XRB) and the feasibility to extract the IGM state and evolution from XRB observations. We build two analytical models, the continuum…
This review summarizes recent studies of the cold neutral hydrogen gas associated with galaxies probed via the HI 21-cm absorption line. HI 21-cm absorption against background radio-loud quasars is a powerful tool to study the neutral gas…
Using a spectral stacking technique, we measure the neutral hydrogen (HI) properties of a sample of galaxies at $z < 0.11$ across 35 pointings of the Westerbork Synthesis Radio Telescope (WSRT). The radio data contains 1,895 galaxies with…
We present JWST/MIRI spectra from the Medium-Resolution Spectrometer of IZw18, a nearby dwarf galaxy with a metallicity of $\sim 3$% Solar. Here, we investigate warm molecular hydrogen, H2, observed in spectra extracted in $\sim 120$ pc…
We present a detailed study of the HI 21cm absorption system at z=0.0912 towards the radio quasar B0738+313. The uncommonly narrow main absorption line and weak secondary line are resolved for the first time. In addition we find it…
We study the X-ray absorption of a complete sample of 99 bright Swift gamma-ray bursts. Over the last few years, a strong correlation between the intrinsic X-ray absorbing column density (N_H(z)) and the redshift was found. This absorption…
We present a study of the small-scale structure of the interstellar medium in the Milky Way. We used HST STIS data to measure N(HI) in a pencil-beam toward 59 AGNs and compared the results with the values seen at 9 arcmin - 36 arcmin…
We investigate the physical state of HI absorbing gas at low redshift (z = 0.25) using a subset of cosmological, hydrodynamic simulations from the OWLS project, focusing in particular on broad (b_HI > 40 km/s) HI Lyman-Alpha absorbers…
We present the high-resolution X-ray spectra of Mkn 421 obtained in November 2003 with the RGS aboard the XMM-Newton satellite. This Target of Opportunity observation was triggered because the source was in a high state of activity in the…
Dark gas in the interstellar medium (ISM) is believed to not be detectable either in CO or Hi radio emission, but it is detected by other means including gamma-rays, dust emission and extinction traced outside the Galactic plane at |b|>5…
We conduct an ultraviolet (HST and FUSE) spectroscopic survey of HI (Lyman lines) and seven metal ions (OVI, NV, CIV, CIII, SiIV, SiIII, FeIII) in the low-redshift intergalactic medium (IGM) at z<0.4. We analyzed 650 Lya absorbers over…
We examine the impact of helium reionization on the structure of the intergalactic medium (IGM). We model the reionization using a radiative transfer (RT) code coupled to the combined gravity hydrodynamics code Enzo. Neutral hydrogen and…
It is known that the GRB equivalent hydrogen column density (NHX) changes with redshift and that, typically, NHX is greater than the GRB host neutral hydrogen column density. We have compiled a large sample of data for GRB NHX and…
We report Arecibo 21 cm absorption-emission observations to characterise the physical properties of neutral hydrogen (HI) in the proximity of five giant molecular clouds (GMCs): Taurus, California, Rosette, Mon OB1, and NGC 2264. Strong HI…
We present 21-cm absorption measurements towards 12 radio continuum sources with previously identified thermally-unstable warm neutral medium (WNM). These observations were obtained with the Expanded Very Large Array (EVLA) and were…
We combine cosmological, hydrodynamical simulations with accurate radiative transfer corrections to investigate the relation between strong HI absorbers (N_HI >~ 10^17 /cm^2) and galaxies at redshift z = 3. We find a strong anti-correlation…
In this Letter we demonstrate that the two claims of $z\simeq 0.03$ OVII K$\alpha$ absorption lines from Warm Hot Intergalactic Medium (WHIM) along the lines of sight to the blazars H~2356-309 (Buote et al., 2009; Fang et al., 2010) and…
We analyzed absorption features arising from interstellar neutral carbon that appeared in the UV spectra of 89 stars recorded in the highest resolution echelle modes of STIS on HST so that we could determine the relative populations of…
We present 21-cm Spectral Line Observations of Neutral Gas with the VLA (21-SPONGE), a Karl G. Jansky Very Large Array (VLA) large project (~600 hours) for measuring the physical properties of Galactic neutral hydrogen (HI). 21-SPONGE is…