Related papers: Gas Phase Distribution in the Neutral ISM: A Compa…
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…
Several different methods are regularly used to infer the properties of the neutral interstellar medium (ISM) using atomic hydrogen (H I) 21cm absorption and emission spectra. In this work, we study various techniques used for inferring ISM…
This paper is a numerical study of the condensation of the warm neutral medium (WNM) into cold neutral medium (CNM) structures under the effect of turbulence and thermal instability. Using low resolution simulations we explored the impact…
The interstellar medium (ISM) consists of a multiphase gas, including the warm neutral medium (WNM), the unstable neutral medium (UNM), and the cold neutral medium (CNM). While significant attention has been devoted to understanding the WNM…
Atomic Hydrogen-21 cm transition (HI) is an excellent tracer to study and understand the properties of the atomic gas in the Galaxy. Using the Westerbork Synthesis Radio Telescope (WSRT), we observed 12 quasar sightlines to detect galactic…
The term "unstable neutral media" (UNM) has traditionally been used to describe the transient phase formed between the warm and cold neutral hydrogen (HI) phases and has not been the focus of HI studies. However, recent observations suggest…
Context. A large fraction of the interstellar medium can be characterized as a multiphase medium. The neutral hydrogen gas is bistable with a cold and warm neutral medium (CNM and WNM respectively) but there is evidence for an additional…
We use three-dimensional numerical hydrodynamic simulations of the turbulent, multiphase atomic interstellar medium (ISM) to construct and analyze synthetic HI 21 cm emission and absorption lines. Our analysis provides detailed tests of 21…
We study the correlation between the non-thermal velocity dispersion ($\sigma_{\rm nth}$) and the length-scale (L) in the neutral interstellar medium (ISM) using a large number of Hi gas components taken from various published Hi surveys…
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…
Neutral hydrogen 21 cm transition is a useful tracer of the neutral interstellar medium. However, inferring physical condition from the observed 21 cm absorption and/or emission spectra is often not straightforward. One complication in…
Much of the interstellar medium in disk galaxies is in the form of neutral atomic hydrogen, H I. This gas can be in thermal equilibrium at relatively low temperatures, T < 300 K (the cold neutral medium, or CNM) or at temperatures somewhat…
In this paper, the nonlinear evolution of a bistable interstellar medium is investigated using two-dimensional simulations with a realistic cooling rate, thermal conduction, and physical viscosity. The calculations are performed using…
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…
We systematically perform hydrodynamics simulations of 20 km s^-1 converging flows of the warm neutral medium (WNM) to calculate the formation of the cold neutral medium (CNM), especially focusing on the mean properties of the multiphase…
Observations of intergalactic neutral hydrogen can provide a wealth of information about structure and galaxy formation, potentially tracing accretion and feedback processes on Mpc scales. Below a column density of NHI ~ 10^19 cm-2, the…
Context: The interstellar medium (ISM) on all scales is full of structures that can be used as tracers of processes that feed turbulence. Aims: We used HI survey data to derive global properties of the angular power distribution of the…
Dust grains are an important component of the interstellar medium (ISM) of galaxies. We present the first direct measurement of the residence times of interstellar dust in the different ISM phases, and of the transition rates between these…
We present new Arecibo 21-cm line measurements of the temperatures of interstellar gas. Our temperatures for the Cold Neutral Medium (CNM) are significantly lower than previous single-dish results and in very good accord with theoretical…
The main goal of this analysis is to present a new method to estimate the physical properties of diffuse cloud of atomic hydrogen observed at high Galactic latitude. This method, based on a comparison of the observations with fractional…