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Related papers: HI and Galactic Structure

200 papers

Imaging of galaxies to study the interstellar medium on scales of a few pc is difficult. However, for the Milky Way galaxy two major Galactic all sky HI 21-cm line surveys will become available soon with unprecedented quality. We present…

Astrophysics of Galaxies · Physics 2009-11-02 Peter M. W. Kalberla , N. M. McClure-Griffiths , J. Kerp

In this contribution I shall focus on the structure of the Galactic thin disk. The evolution of the thin disk and its chemical properties have been discussed in detail by T. Bensby's contribution in conjunction with the properties of the…

Astrophysics of Galaxies · Physics 2015-06-16 Giovanni Carraro

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…

Astrophysics · Physics 2008-11-26 Avinash A. Deshpande

The extra-planar H I in the inner parts of the Milky Way has been discovered to contain numerous cloud-like structures when observed in the 21cm line with the Green Bank Telescope (GBT). These halo clouds have motions consistent with…

Astrophysics · Physics 2009-09-29 Felix J. Lockman , Yurii Pidopryhora

Filamentary structure is important for the ISM and star formation. Galactic distribution of filaments may regulate the star formation rate in the Milky Way. However, interstellar filaments are intrinsically complex, making it difficult to…

Astrophysics of Galaxies · Physics 2024-06-12 Ke Wang , Yifei Ge , Tapas Baug

We report the discovery of nineteen new HI shells in the Southern Galactic Plane Survey (SGPS). These shells, which range in radius from 40 pc to 1 kpc, were found in the low resolution Parkes portion of the SGPS dataset, covering Galactic…

Astrophysics · Physics 2009-11-07 N. M. McClure-Griffiths , John M. Dickey , B. M. Gaensler , A. J. Green

The nature of the spiral structure of the Milky Way has long been debated. Only in the last decade have astronomers been able to accurately measure distances to a substantial number of high-mass star-forming regions, the classic tracers of…

Astrophysics of Galaxies · Physics 2016-10-05 Ye Xu , Mark Reid , Thomas Dame , Karl Menten , Nobuyuki Sakai , Jingjing Li , Andreas Brunthaler , Luca Moscadelli , Bo Zhang , Xingwu Zheng

The atomic hydrogen gas (HI) disk in the outer region (beyond ~10 kpc from the centre) of Milky Way can provide valuable information about the structure of the dark matter halo. The recent 3-D thickness map of the outer HI disk from the all…

Astrophysics of Galaxies · Physics 2011-02-11 Kanak Saha , Evan S. Levine , Chanda J. Jog , Leo Blitz

Little is known about the portion of the Milky Way lying beyond the Galactic center at distances of more than 9 kilo-parsec from the Sun. These regions are opaque at optical wavelengths due to absorption by interstellar dust, and distances…

Astrophysics of Galaxies · Physics 2017-10-19 Alberto Sanna , Mark J. Reid , Thomas M. Dame , Karl M. Menten , Andreas Brunthaler

The structural parameters of a galaxy can be used to gain insight into its formation and evolution history. In this paper, we strive to compare the Milky Way's structural parameters to other, primarily edge-on, spiral galaxies in order to…

Astrophysics of Galaxies · Physics 2024-01-09 Jacob A. Guerrette , Aleksandr V. Mosenkov , Dallin Spencer , Zacory D. Shakespear

The spiral structure of our Milky Way has not yet been well outlined. HII regions, giant molecular clouds (GMCs) and 6.7-GHz methanol masers are primary tracers for spiral arms. We collect and update the database of these tracers which has…

Astrophysics of Galaxies · Physics 2013-05-01 L. G. Hou , J. L. Han

The spatial distribution of the gaseous components of the Milky Way is of great importance for a number of different fields, for example, Galactic structure, star formation, and cosmic rays. However, obtaining distance information to…

We combine CaII/NaI absorption and HI 21 cm emission line measurements to analyse the metal abundances, the distribution, the small-scale structure, and the physical conditions of intermediate- and high-velocity gas in the Galactic halo.

Astrophysics · Physics 2009-11-11 Nadya Ben Bekhti , Philipp Richter , Tobias Westmeier

We present a study of the filamentary structure in the atomic hydrogen (HI) emission at the 21 cm wavelength toward the Galactic plane using the observations in the HI4PI survey. Using the Hessian matrix method across radial velocity…

(Sub-)millimeter spectral lines can be used not only to understand the chemical complexity and enrichment history of an observed portion of our Galaxy, but with spectrally resolved lines, they reveal the physical conditions, dynamics, and…

Context: The past decade has witnessed a large number of Galactic plane surveys at angular resolutions below 20". However, no comparable high-resolution survey exists at long radio wavelengths around 21cm in line and continuum emission.…

Stellar halos of galaxies retain crucial clues to their mass assembly history. It is in these galactic components that the remains of cannibalised galactic building blocks are deposited. For the case of the Milky Way, the opportunity to…

Astrophysics of Galaxies · Physics 2024-04-29 Danny Horta , Ricardo P. Schiavon

We outline the case for a comprehensive wide and deep survey ultimately targeted at obtaining 21-cm HI line emission spectroscopic observations of more than a billion galaxies to redshift z=1.5 and greater over half the sky. This survey…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-05 Steven T. Myers , Filipe B. Abdalla , Chris Blake , Leon Koopmans , Joseph Lazio , Steve Rawlings

The ongoing large spectroscopic surveys of the Milky Way such as SEGUE and RAVE have enabled us to take a fresh look at the structure of the Galactic thin and thick disks, and how their structure fits within the framework of structure…

Astrophysics of Galaxies · Physics 2012-06-01 Matthias Steinmetz

We present a new catalogue of spectrophotometric distances and line-of-sight systemic velocities to 103 HII regions between 90$^{\circ}\leq \ell \leq~$195$^{\circ}$ (longitude quadrants II and part of III). Two new velocities for each…

Astrophysics of Galaxies · Physics 2015-10-21 Tyler J. Foster , Christopher M. Brunt