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Related papers: HI scale height in dwarf galaxies

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Mapping stars and gas in nearby galaxies is fundamental for understanding their growth and the impact of their environment. This issue is addressed by comparing the stellar "edges" of galaxies $D_{\rm stellar}$, defined as the outermost…

Context. Gas within a galaxy is forced to establish pressure balance against gravitational forces. The shape of an unperturbed gaseous disk can be used to constrain dark matter models. Aims. We derive the 3-D HI volume density distribution…

Astrophysics · Physics 2009-11-13 P. M. W. Kalberla , L. Dedes , J. Kerp , U. Haud

Gas velocity dispersions provide important diagnostics of the forces counteracting gravity to prevent collapse of the gas. We use the 21 cm line of neutral atomic hydrogen (HI) to study HI velocity dispersion and HI phases as a function of…

Astrophysics of Galaxies · Physics 2015-08-06 R. Ianjamasimanana , W. J. G. de Blok , Fabian Walter , George H. Heald , Anahi Caldu-Primo , Thomas H. Jarrett

We use high-resolution cosmological zoom-in simulations from the FIRE project to make predictions for the covering fractions of neutral hydrogen around galaxies at z=2-4. These simulations resolve the interstellar medium of galaxies and…

Astrophysics of Galaxies · Physics 2015-06-22 C. -A. Faucher-Giguere , P. F. Hopkins , D. Keres , A. L. Muratov , E. Quataert , N. Murray

The vertical distribution of cold neutral hydrogen (HI) clouds is a constraint on models of the structure, dynamics, and hydrostatic balance of the interstellar medium. In 1978, Crovisier pioneered a method to infer the vertical…

Astrophysics of Galaxies · Physics 2024-03-29 Trey V. Wenger , Daniel R. Rybarczyk , Snežana Stanimirović

The vertical scaleheight of the atomic hydrogen gas shows a remarkably flat distribution with the galactocentric radius in the inner Galaxy. This has been a long-standing puzzle (Oort 1962) because the gas scaleheight should increase with…

Astrophysics · Physics 2009-11-07 Chaitra A. Narayan , Chanda J. Jog

The oxygen gradient of four dS galaxies has been determined using abundances for several HII regions determined with four different methods. The gradient slopes of the three non-barred galaxies in the sample are quite steep, larger than…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-05 A. M. Hidalgo-Gamez , D. Ramirez-Fuentes , J. J. Gonzalez

The distribution of various interstellar gas components and the pressure in the interstellar medium (ISM) is a result of the interplay of different dynamical mechanisms and energy sources on the gas in the Milky Way. The scale heights of…

Astrophysics of Galaxies · Physics 2015-06-19 W. D. Langer , J. L. Pineda , T. Velusamy

The atomic hydrogen (HI) properties of star-forming galaxies in the local Universe are known to correlate with other galaxy properties via the ``HI scaling relations''. The redshift evolution of these relations serves as an important…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-14 Apurba Bera , Nissim Kanekar , Jayaram N. Chengalur , Jasjeet S. Bagla

Several measures of galaxy size and mass obtained from the neutral hydrogen mapping of 70 dwarf irregular galaxies presented in Paper I (Hoffman et al. 1996) are compared statistically to those for the set of all available HI-mapped dwarfs…

Astrophysics · Physics 2009-10-28 E. E. Salpeter , G. L. Hoffman

The observed rotation curves of disc galaxies, ranging from late-type dwarf galaxies to early-type spirals, can be fit remarkably well simply by scaling up the contributions of the stellar and HI discs. This `baryonic scaling model' can…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 R. A. Swaters , R. Sancisi , J. M. van der Hulst , T. S. van Albada

We study the relationship between the scale-height of the molecular gas disc and the turbulent velocity dispersion of the molecular interstellar medium within a simulation of a Milky Way-like galaxy in the moving-mesh code Arepo. We find…

Astrophysics of Galaxies · Physics 2022-07-20 Sarah M. R. Jeffreson , Jiayi Sun , Christine D. Wilson

We present the global scaling relations between the neutral atomic hydrogen gas, the stellar disk and the star forming disk in a sample of 228 nearby galaxies that are both spatially and spectrally resolved in HI line emission. We have used…

Astrophysics of Galaxies · Physics 2021-01-14 Elizabeth Naluminsa , Edward C. Elson , Thomas H. Jarrett

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…

In order to investigate the contribution of diffuse components to their total HI emission, we have obtained high precision HI line flux densities with the 100m Green Bank Telescope for a sample of 100 isolated spiral and irregular galaxies…

Astrophysics · Physics 2008-11-26 David E. Hogg , Morton S. Roberts , Martha P. Haynes , Ronald J. Maddalena

The observed high covering fractions of neutral hydrogen (HI) with column densities above $\sim 10^{17} \rm{cm}^{-2}$ around Lyman-Break Galaxies (LBGs) and bright quasars at redshifts z ~ 2-3 has been identified as a challenge for…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-25 Alireza Rahmati , Joop Schaye , Richard G. Bower , Robert A. Crain , Michelle Furlong , Matthieu Schaller , Tom Theuns

The interstellar gas in spiral galaxies can constitute a significant fraction of the baryon mass and it has been demonstrated that the sum of stellar and gas components correlates well with the kinematic signature of the total mass content,…

Astrophysics of Galaxies · Physics 2022-02-16 Ehsan Kourkchi , R. Brent Tully , Helene M. Courtois , Alexandra Dupuy , Daniel Guinet

We revisit the HI size-mass (D$_{\rm HI}$-M$_{\rm HI}$) relation of galaxies with a sample of more than 500 nearby galaxies covering over five orders of magnitude in HI mass and more than ten $B$-band magnitudes. The relation is remarkably…

We investigate the diversity in the sizes and average surface densities of the neutral atomic hydrogen (HI) gas discs in ~280 nearby galaxies detected by the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). We combine the…

We introduce the "Bluedisk" project, a large program at the Westerbork Synthesis Radio Telescope (WSRT) that has mapped the HI in a sample of 23 nearby galaxies with unusually high HI mass fractions, along with a similar-sized sample of…