English
Related papers

Related papers: Extracting the cold neutral medium from HI emissio…

200 papers

Observations from the HUT and the HST have recently detected HeII absorption along the lines of sight to two high redshift quasars. We use cosmological simulations with gas dynamics to investigate HeII absorption in the cold dark matter…

Astrophysics · Physics 2009-10-28 Rupert A. C. Croft , David H. Weinberg , Neal Katz , Lars Hernquist

We discuss an implementation of a deep learning framework to gain insight into dark matter (DM) structure formation. We investigate the contribution of velocity and density field information to the construction of the halo mass function…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-13 Saba Etezad-Razavi , Erfan Abbasgholinejad , Mohammad-Hadi Sotoudeh , Farbod Hassani , Sadegh Raeisi , Shant Baghram

In neutral hydrogen (HI) galaxy survey, a significant challenge is to identify and extract the HI galaxy signal from observational data contaminated by radio frequency interference (RFI). For a drift-scan survey, or more generally a survey…

Instrumentation and Methods for Astrophysics · Physics 2023-04-27 Ruxi Liang , Furen Deng , Zepei Yang , Chunming Li , Feiyu Zhao , Botao Yang , Shuanghao Shu , Wenxiu Yang , Shifan Zuo , Yichao Li , Yougang Wang , Xuelei Chen

We explore the possibility of detecting HI 21cm absorption by the neutral intergalactic medium (IGM) toward very high redshift radio sources. The epoch considered is between the time when the first ionizing sources form and when the bulk of…

Astrophysics · Physics 2016-08-30 C. Carilli , N. Y. Gnedin , F. Owen

Modelling the distribution of neutral hydrogen (HI) in dark matter halos is important for studying galaxy evolution in the cosmological context. We use a novel approach to infer the HI-dark matter connection at the massive end ($m_{\rm HI}…

Astrophysics of Galaxies · Physics 2018-06-12 Niladri Paul , Tirthankar Roy Choudhury , Aseem Paranjape

Very sensitive HI 21cm observations have been made in 860 directions at dec >= -43deg in search of weak, Galactic, high-velocity HI emission lines at moderate and high Galactic latitudes. One-third of the observations were made toward…

Astrophysics · Physics 2009-11-07 Felix J. Lockman , Edward M. Murphy , Sara Petty-Powell , Vincent J. Urick

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…

Astrophysics of Galaxies · Physics 2018-10-10 Claire E. Murray , Snezana Stanimirovic , W. M. Goss , Carl Heiles , John M. Dickey , Brian Babler , Chang-Goo Kim

21-cm intensity mapping (IM) is a powerful technique to probe the large-scale distribution of neutral hydrogen (HI) and extract cosmological information such as the baryon acoustic oscillation feature. A key challenge lies in recovering the…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-24 Zitong Wang , Feng Shi , Le Zhang , Yanming Liu , Xiaoping Li , Shulei Ni , Ming Jiang , Xiaofan Ma

This is the first in a series of three papers describing a project with the Cosmic Origins Spectrograph on the Hubble Space Telescope to measure abundances of the neutral interstellar medium (ISM) in a sample of 9 nearby star-forming…

Astrophysics of Galaxies · Physics 2015-06-22 Bethan L. James , Alessandra Aloisi , Timothy M. Heckman , Sangmo Tony Sohn , Michael A. Wolfe

We have used the WHAM H_alpha survey and Leiden/Dwingeloo HI data to decompose the Far-infrared emission (from 100 to 1000 micron) at high Galactic latitude into components associated with the Warm Ionised Medium (WIM) and the Warm Neutral…

Astrophysics · Physics 2011-03-28 G. Lagache , L. M. Haffner , R. J. Reynolds , S. L. Tufte

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…

Astrophysics of Galaxies · Physics 2023-11-27 Soumyadeep Bhattacharjee , Nirupam Roy , Prateek Sharma , Amit Seta , Christoph Federrath

Galaxy disks are shown to contain a significant population of atomic clouds of 100pc linear size which are self-opaque in the 21cm transition. These objects have HI column densities as high as 10^23 and contribute to a global opacity…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Robert Braun

Neutral hydrogen (HI) is the primary component of the cool interstellar medium (ISM) and is the reservoir of fuel for star formation. Owing to the sensitivity of existing radio telescopes, our understanding of the evolution of the ISM in…

Line intensity mapping (LIM) is an emerging observational method to study the large-scale structure of the Universe and its evolution. LIM does not resolve individual sources but probes the fluctuations of integrated line emissions. A…

Astrophysics of Galaxies · Physics 2020-06-03 Kana Moriwaki , Nina Filippova , Masato Shirasaki , Naoki Yoshida

Filaments stand as pivotal structures within the cosmic web. However, direct detection of the cold gas content of the filaments remains challenging due to its inherent low brightness temperature. With the TNG hydrodynamical simulations, we…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-10 Diyang Liu , Yichao Li , Denis Tramonte , Furen Deng , Jiaxin Wang , Yougang Wang , Xin Zhang , Xuelei Chen

Ionized carbon is the main gas-phase reservoir of carbon in the neutral diffuse interstellar medium and its 158 micron fine structure transition [CII] is the most important cooling line of the diffuse interstellar medium (ISM). We combine…

HI 21~cm absorption spectroscopy provides an excellent probe of the neutral gas content of absorbing galaxies, yielding information on their kinematics, mass, physical size and ISM conditions. The high sensitivity, unrivaled frequency…

Astrophysics · Physics 2009-11-10 N. Kanekar , F. H. Briggs

Interstellar reddening corrections are necessary to reconstruct the intrinsic spectral energy distributions (SEDs) of accreting protostellar systems. The stellar SED determines the heating and chemical processes that can occur in…

We investigate the column density distribution function of neutral hydrogen at redshift z = 3 using a cosmological simulation of galaxy formation from the OverWhelmingly Large Simulations (OWLS) project. The base simulation includes…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-04 Gabriel Altay , Tom Theuns , Joop Schaye , Neil H. M. Crighton , Claudio Dalla Vecchia

Measuring the properties of the cold neutral medium (CNM) in low-metallicity galaxies provides insight into heating and cooling mechanisms in early Universe-like environments. We report detections of two localized atomic neutral hydrogen…