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相关论文: Small-Scale HI Channel Map Structure is Cold: Evid…

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We investigate the physical properties of structures seen in channel map observations of 21-cm neutral hydrogen (HI) emission. HI intensity maps display prominent linear structures that are well aligned with the ambient magnetic field in…

星系天体物理 · 物理学 2019-04-11 S. E. Clark , J. E. G. Peek , M. -A. Miville-Deschênes

Physical properties of the tiny scale structures in the cold neutral medium (CNM) of galaxies is a long-standing puzzle. Only a few lines of sights in our Galaxy have been studies with mixed results on the scale-invariant properties of such…

星系天体物理 · 物理学 2020-01-08 P. K. Vishwakarma , P. Dutta

Using the DensePak fiber optic array on the KPNO WIYN telescope, we have obtained high S/N echelle spectra of the Na I D wavelength region toward the central 27" x 43" of the globular cluster M15 at a spatial resolution of 4". The spectra…

天体物理学 · 物理学 2009-10-31 David M. Meyer , J. T. Lauroesch

We have used integral field echelle spectroscopy with the DensePak fiber-optic array on the KPNO WIYN telescope to observe the central 27" x 43" of the globular cluster M92 in the Na I D wavelength region at a spatial resolution of 4". Two…

天体物理学 · 物理学 2009-11-06 Sean M. Andrews , David M. Meyer , J. T. Lauroesch

Context. The interstellar medium is affected by turbulence and observed H i structures in channel maps are shaped by turbulent motions. It is taken for granted by a few theoreticians that observed H i structures do not represent real…

星系天体物理 · 物理学 2021-01-05 P. M. W. Kalberla , U. Haud

We aim at analysing systematically the distribution and physical properties of neutral and mildly ionised gas in the Milky Way halo, based on a large absorption-selected data set. Multi-wavelength studies were performed combining optical…

星系天体物理 · 物理学 2015-06-04 N. Ben Bekhti , B. Winkel , P. Richter , J. Kerp , U. Klein , M. T. Murphy

Resolving the phase structure of neutral hydrogen (HI) is crucial for understanding the life cycle of the interstellar medium (ISM). However, accurate measurements of HI temperature and density are limited by the availability of background…

星系天体物理 · 物理学 2020-08-19 Claire E. Murray , J. E. G. Peek , Chang-Goo Kim

Tracing the transition between the diffuse atomic interstellar medium (ISM) and cold, dense gas is crucial for deciphering the star formation cycle in galaxies. Here we present MACH, a new survey of cold neutral hydrogen (HI) absorption at…

Galactic neutral hydrogen (HI) within a few hundred parsecs of the Sun contains structure with an angular distribution that is similar to small-scale structure observed by the Wilkinson Microwave Anisotropy Probe (WMAP). A total of 108…

宇宙学与河外天体物理 · 物理学 2015-05-18 Gerrit L. Verschuur

Spatial associations have been found between interstellar neutral hydrogen (HI) emission morphology and small-scale structure observed by the Wilkinson Microwave Anisotropy Probe (WMAP) in an area bounded by l = 60 & 180 deg, b = 30 & 70…

天体物理学 · 物理学 2009-11-13 Gerrit L. Verschuur

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…

We present high S/N measurements of the H I Ly alpha absorption line toward 16 Galactic targets which are at distances between approximately 190 and 2200 pc, all beyond the wall of the Local Bubble. We describe the models used to remove…

星系天体物理 · 物理学 2023-04-05 S. D. Friedman , P. Chayer , E. B. Jenkins , T. M. Tripp , G. M. Williger , G. Hebrard , P. Sonnentrucker

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…

天体物理学 · 物理学 2008-11-26 Avinash A. Deshpande

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.

天体物理学 · 物理学 2015-05-13 N. Ben Bekhti , M. Murphy , P. Richter , T. Westmeier

Obtaining a complete census of gas in the local interstellar medium (<100 pc) is challenging given the limited available tracers of the warm, partially-ionized medium. Medium-to-high resolution UV absorption spectroscopy toward individual…

Diffuse emission in the mid-infrared shows a wealth of structure, that lends itself to high-resolution structure analysis of the interstellar gas. A large part of the emission comes from polycyclic aromatic hydrocarbons, excited by nearby…

天体物理学 · 物理学 2008-11-26 F. Heitsch , B. Whitney , R. Indebetouw , M. R. Meade , B. L. Babler , E. Churchwell , ;

The spatial distribution of neutral hydrogen (HI) in the Universe contains a wealth of cosmological information. The 21 cm emission line can be used to map the HI up to very high redshift and therefore reveal us something about the…

宇宙学与河外天体物理 · 物理学 2017-08-09 Emanuele Castorina , Francisco Villaescusa-Navarro

We present new high resolution (R>50,000) absorption measurements of the NaI doublet (5889 - 5895A) along 482 nearby sight-lines, in addition to 807 new measurements of the CaII K (3933A) absorption line. We have combined these new data…

星系天体物理 · 物理学 2015-05-14 Barry Y. Welsh , Rosine Lallement , Jean-Luc Vergely , Severine Raimond

This paper reports dual-epoch, Very Long Baseline Array observations of H I absorption toward 3C 147. One of these epochs (2005) represents new observations while one (1998) represents the reprocessing of previous observations to obtain…

星系天体物理 · 物理学 2009-11-13 T. Joseph W. Lazio , C. L. Brogan , W. M. Goss , S. Stanimirovic

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…

宇宙学与河外天体物理 · 物理学 2015-05-13 Attila Popping , Romeel Dave , Robert Braun , Benjamin D. Oppenheimer
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