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相关论文: Hydrogen volume densities in nearby galaxies I - a…

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We derive total (atomic + molecular) hydrogen densities in giant molecular clouds (GMCs) in the nearby spiral galaxy M33 using a method that views the atomic hydrogen near regions of recent star formation as the product of…

星系天体物理 · 物理学 2015-05-27 J. S. Heiner , R. J. Allen , P. C. van der Kruit

Recent submillimeter and far-infrared wavelength observations of absorption in the rotational ground-state lines of various simple molecules against distant Galactic continuum sources have opened the possibility of studying the chemistry of…

星系天体物理 · 物理学 2017-02-21 B. Winkel , H. Wiesemeyer , K. M. Menten , M. Sato , A. Brunthaler , F. Wyrowski , D. Neufeld , M. Gerin , N. Indriolo

Due to our vantage point in the disk of the Galaxy, its 3D structure is not directly accessible. However, knowing the spatial distribution, e.g. of atomic and molecular hydrogen gas is of great importance for interpreting and modelling…

星系天体物理 · 物理学 2023-09-26 Laurin Söding , Philipp Mertsch , Vo Hong Minh Phan

We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photo-…

天体物理学 · 物理学 2009-10-30 Marco Spaans , David A. Neufeld

We describe a phenomenological model for molecular hydrogen formation suited for applications in galaxy formation simulations, which includes on-equilibrium formation of molecular hydrogen on dust and approximate treatment of both its…

天体物理学 · 物理学 2010-12-28 Nickolay Y. Gnedin , Konstantinos Tassis , Andrey V. Kravtsov

We present a method to estimate the total gas column density, dust-to-gas and dust-to-metal ratios of distant galaxies from rest-frame optical spectra. The technique exploits the sensitivity of certain optical lines to changes in depletion…

宇宙学与河外天体物理 · 物理学 2015-06-15 Jarle Brinchmann , Stéphane Charlot , Guinevere Kauffmann , Tim Heckman , Simon D. M. White , Christy Tremonti

This study is aimed to contribute to a more comprehensive understanding of the molecular hydrogen distribution in the galaxy M33 by introducing novel methods for generating high angular resolution (18.2$''$, equivalent to 75 pc) column…

We use spectral stacking to measure the contribution of galaxies of different masses and in different hierarchies to the cosmic atomic hydrogen (HI) mass density in the local Universe. Our sample includes 1793 galaxies at $z < 0.11$…

Using observed GALEX far-ultraviolet (FUV) fluxes and VLA images of the 21-cm HI column densities, along with estimates of the local dust abundances, we measure the volume densities of a sample of actively star-forming giant molecular…

天体物理学 · 物理学 2009-11-13 Jonathan S. Heiner , Ronald J. Allen , O. Ivy Wong , Pieter C. van der Kruit

We present a multi-scale analysis of molecular hydrogen in a Milky Way-like simulated galaxy. Our census covers the gas content of the entire disc, to radial profiles and the Kennicutt-Schmidt relation, to a study of its molecular clouds,…

星系天体物理 · 物理学 2019-01-16 Sarah Nickerson , Romain Teyssier , Joakim Rosdahl

HI features near young star clusters in M81 are identified as the photodissociated surfaces of Giant Molecular Clouds (GMCs) from which the young stars have recently formed. The HI column densities of these features show a weak trend, from…

天体物理学 · 物理学 2008-11-26 Jonathan S. Heiner , Ronald J. Allen , Bjorn H. C. Emonts , Pieter C. van der Kruit

We compare the mass and internal distribution of atomic hydrogen (HI) in 2200 present-day central galaxies with M_star > 10^10 M_Sun from the 100 Mpc EAGLE Reference simulation to observational data. Atomic hydrogen fractions are corrected…

We present a new observational method to evaluate the star formation law as formulated by Schmidt: the power-law expression assumed to relate the rate of star formation in a volume of space to the local total gas volume density. Volume…

星系天体物理 · 物理学 2015-05-19 J. S. Heiner , R. J. Allen , P. C. van der Kruit

Molecular hydrogen (H2) is the primary component of the reservoirs of cold, dense gas that fuel star formation in our galaxy. While the H2 abundance is ultimately regulated by physical processes operating on small scales in the interstellar…

宇宙学与河外天体物理 · 物理学 2015-06-11 Robert Feldmann , Jose Hernandez , Nickolay Y. Gnedin

We derive radial and vertical distributions of HI and H2 gas densities in our Galaxy by using the terminal velocity method. We calculate the molecular fraction (f_mol) defined as the ratio of the molecular hydrogen to total hydrogen gas…

天体物理学 · 物理学 2007-05-23 K. Imamura , Y. Sofue

In order to interpret H2 (molecular hydrogen) quasar absorption line observations of damped Ly-alpha systems (DLAs) and sub-DLAs, we model their H2 abundance as a function of dust-to-gas ratio, including H2 self-shielding and dust…

天体物理学 · 物理学 2009-11-10 H. Hirashita , A. Ferrara

Modern observations of the interstellar medium (ISM) in galaxies detect a variety of atomic and molecular species. The goal is to connect these observations to the astrochemical properties of the ISM. 3D hydro-chemical simulations attempt…

星系天体物理 · 物理学 2019-02-20 Thomas G. Bisbas , Andreas Schruba , Ewine F. van Dishoeck

We apply novel survival analysis techniques to investigate the relationship between a number of the properties of galaxies and their atomic ($M_\mathrm{HI}$) and molecular ($M_{\mathrm{H_2}}$) gas mass, with the aim of devising efficient,…

星系天体物理 · 物理学 2019-11-06 Hassen M. Yesuf , Luis C. Ho

We report the first ensemble results from the FUSE survey of molecular hydrogen in lines of sight with A_V $\gtrsim$ 1 mag. We have developed techniques for fitting computed profiles to the low-J lines of H2, and thus determining column…

We propose to employ emission line luminosities obtained via optical spectroscopy to estimate the content of neutral hydrogen (HI) in galaxies. We use the optical spectroscopy data from the Mapping of Nearby Galaxies at APO (MaNGA) survey…

星系天体物理 · 物理学 2023-12-07 Dmitry Bizyaev
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