Related papers: HI column density statistics of the cold neutral m…

Observations of extragalactic objects need to be corrected for Galactic absorption and this is often accomplished by using the measured 21 cm HI column. However, within the beam of the radio telescope there are variations in the HI column…

We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We…

We present the first localized detections of the cold neutral medium (CNM) in IC10, offering a rare view of dense atomic gas in a low-metallicity (0.27 solar metallicity) dwarf galaxy. As a low-metallicity starburst, IC10's interstellar…

During the past decade or so, measurements of Galactic HI absorption using VLBI against extra-galactic sources, as well as multi-epoch observatios in pulsar directions, have detected small-scale transverse variations corresponding to tens…

We present a study of the cold atomic hydrogen (HI) content of molecular clouds simulated within the SILCC-Zoom project. We produce synthetic observations of HI at 21 cm including HI self-absorption (HISA) and observational effects. We find…

We present a neutral hydrogen-selected absorption-line survey of gas with HI column densities 15<log N(HI)<19 at z<1 using the Cosmic Origins Spectrograph on the Hubble Space Telescope. Our main aim is to determine the metallicity…

Very sensitive HI absorption spectra (tau RMS about 10^-4 over 1 km/s) toward high latitude QSOs have revealed a population of tiny discrete features in the diffuse ISM with peak tau of 0.1 - 2% and core line-widths corresponding to…

Hydrogen column densities inferred from X-ray absorption are typically 5 - 30 times larger than the neutral atomic hydrogen column densities derived from 21cm HI absorption toward radio-loud active galactic nuclei. Some part of the…

We have studied the small scale distribution of atomic hydrogen (HI) using 21-cm absorption spectra against multiple-component background radio continuum sources from the 21-SPONGE survey and the Millennium Arecibo Absorption Line Survey.…

We discuss physical conditions in Galactic neutral hydrogen based on deep, high velocity resolution interferometric HI 21 cm absorption spectroscopy towards 33 compact extra-galactic radio sources. The HI 21 cm optical depth spectra have…

We investigate data from the Galactic Effelsberg--Bonn HI Survey (EBHIS), supplemented with data from the third release of the Galactic All Sky Survey (GASS III) observed at Parkes. We explore the all sky distribution of the local Galactic…

We investigate the prospects for detecting and constraining density and temperature inhomogeneities in the circumgalactic medium (CGM) using absorption measurements of metal ions. Distributions in the gas thermal properties could arise from…

We carried out synthetic observations of interstellar atomic hydrogen at 21cm wavelength by utilizing the magneto-hydrodynamical numerical simulations of the inhomogeneous turbulent interstellar medium (ISM) Inoue and Inutsuka (2012). The…

Context. In the HI line profiles in the Leiden-Argentina-Bonn (LAB) all-sky database, we have found a population of very cold HI clouds. So far, the role of these clouds in the interstellar medium (ISM) has remained unclear. Aims. In this…

We use the millennium Arecibo 21 cm absorption-line survey measurements to examine the issue of the non-thermal contribution to the observed Galactic HI line widths. If we assume a simple, constant pressure model for the HI in the Galaxy,…

We generate synthetic HI Galactic plane surveys from spiral galaxy simulations which include stellar feedback processes. Compared to a model without feedback we find an increased scale height of HI emission (in better agreement with…

Simulations predict that galaxies grow primarily through the accretion of gas that has not gone through an accretion shock near the virial radius and that this cold gas flows towards the central galaxy along dense filaments and streams.…

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…

Neutral hydrogen (HI) emission exhibits complex morphology that encodes rich information about the physics of the interstellar medium (ISM). We apply the scattering transform (ST) to characterize HI emission structure via a set of compact…

We present a census of neutral gas in the Milky Way disk and halo down to limiting column densities of $N$(HI)$\sim10^{14}$ cm$^{-2}$ using measurements of HI Lyman-series absorption from the Far Ultraviolet Spectroscopic Explorer (FUSE).…