Related papers: Probing the parameters of the intergalactic medium…

We present a detailed study of the hydrogen density distribution in the local interstellar medium (ISM) using the X-ray absorption technique. Hydrogen column densities were precisely measured by fitting X-ray spectra from coronal sources…

We report on the observed properties of the plasma revealed through high signal-to-noise (S/N) observations of 54 intervening O VI absorption systems containing 85 O VI and 133 H I components in a blind survey of 14 QSOs observed at ~18 km…

The Intergalactic Medium (IGM) contains $>$50% of the baryonic mass of the Universe, yet the mechanisms responsible for keeping the IGM ionized has not been fully explained. Hence, we investigate ion abundances from the largest blind QSO…

The interstellar medium (ISM) has a multiphase structure characterized by gas, dust and molecules. The gas can be found in different charge states: neutral, low-ionized (warm) and high-ionized (hot). It is possible to probe the multiphase…

Low-ionization metal absorption lines provide a primary probe of cool gas in and around galaxies. We confront observations of metal-line absorption in quasar spectra with predictions from the IllustrisTNG cosmological simulation in order to…

We present basic data and modeling for a survey of the cool, photo-ionized Circum-Galactic Medium (CGM) of low-redshift galaxies using far-UV QSO absorption line probes. This survey consists of "targeted" and "serendipitous" CGM subsamples,…

Nitrogen is one of the most abundant metals in the interstellar medium (ISM), and thus it constitutes an excellent test to study a variety of astrophysical environments, ranging from nova to active galactic nuclei. We present a detailed…

Numerical simulations predict that a large number of baryons reside in intergalactic space at temperatures between 10^5-10^7 K. Highly-ionized metals, such as O VII and O VIII, are good tracers of this ``warm-hot intergalactic medium'', or…

We decompose the Lyman-{\alpha} (Ly{\alpha}) forest of an extensive sample of 74 high signal-to-noise ratio and high-resolution quasar spectra into a collection of Voigt profiles. Absorbers located near caustics in the peculiar velocity…

Intergalactic scintillation of distant quasars is sensitive to free electrons and therefore complements Ly$\alpha$ absorption line experiments probing the neutral intergalactic medium (IGM). We present a new scheme to compute IGM refractive…

The power spectra of the redshifted 21-cm signal from the Epoch of Reionization (EoR) contain information about the ionization and thermal states of the intergalactic medium (IGM), and depend on the properties of the EoR sources. Recently,…

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…

The radiation background produced by the 21 cm spin-flip transition of neutral hydrogen at high redshifts can be a pristine probe of fundamental physics and cosmology. At z~30-300, the intergalactic medium (IGM) is visible in 21 cm…

We examine the Ly-alpha absorber population at z<0.3 detected in spectra of the QSOs PG0953+415 and H1821+643 taken with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. We compare their statistical properties to…

We present an argument for a {\it lower limit} to the Compton-$y$ parameter describing spectral distortions of the cosmic microwave background (CMB). The absence of a detectable Gunn-Peterson signal in the spectra of high redshift quasars…

We derive constraints on the thermal and ionization states of the intergalactic medium (IGM) at redshift $\approx$ 9.1 using new upper limits on the 21-cm power spectrum measured by the LOFAR radio-telescope and a prior on the ionized…

The origin of warm ions in the circum-galactic medium (CGM) surrounding massive galaxies remains a mystery. In this paper, we argue that a significant fraction of the observed warm-ion columns may arise in the intergalactic medium (IGM)…

Recent studies have revealed a dynamic interplay between the galaxy ecosystem and the circumgalactic medium (CGM). We investigate the CGM at high redshifts (z $\gtrsim$ 2) by using bright afterglows of gamma-ray bursts (GRB) as background…

We use high-quality, medium-resolution {\it Hubble Space Telescope}/Cosmic Origins Spectrograph (\HST/COS) observations of 82 UV-bright AGN at redshifts $z_{AGN}<0.85$ to construct the largest survey of the low-redshift intergalactic medium…

We present a study exploring the nature and properties of the Circum-Galactic Medium (CGM) and its connection to the atomic gas content in the interstellar medium (ISM) of galaxies as traced by the HI 21cm line. Our sample includes 45 low-z…