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Related papers: Tiny HI Clouds in the Local ISM

200 papers

We present a detailed 1.2 mm continuum and CS spectral line study of a large sample of 69 massive star forming regions in very early stages of evolution, most of them prior to building up an ultracompact HII region. The continuum data show…

Astrophysics · Physics 2009-11-07 H. Beuther , P. Schilke , K. M. Menten , F. Motte , T. K. Sridharan , F. Wyrowski

We present dust column densities and dust temperatures for $\sim3000$ young high-mass molecular clumps from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey, derived from adjusting single temperature dust emission models to the…

Solar and Stellar Astrophysics · Physics 2015-12-24 Andrés E. Guzmán , Patricio Sanhueza , Yanett Contreras , Howard A. Smith , James M. Jackson , Sadia Hoq , Jill M. Rathborne

We propose a method to determine the power spectrum of \HI column density fluctuations using radio-interferometric observations of 21-cm emission from the ISM of galaxies. We have used this to estimate the power spectra of six nearly face…

Astrophysics of Galaxies · Physics 2015-06-16 Prasun Dutta , Somnath Bharadwaj

Maps of the 450 micron and 850 micron dust continuum emission from three star-forming condensations within the Lynds 1630 molecular cloud, made with the SCUBA bolometer array, reveal the presence of four new submillimetre sources, each of a…

Astrophysics · Physics 2009-11-07 Robin R. Phillips , Andy G. Gibb , Leslie T. Little

We report the discovery of eleven high-velocity HI clouds at Galactic latitudes of 25-30 degrees, likely embedded in the Milky Way's nuclear wind. The clouds are detected with deep Green Bank Telescope 21 cm observations of a $3.2^\circ…

Astrophysics of Galaxies · Physics 2025-07-08 Rongmon Bordoloi , Andrew J. Fox , Felix J. Lockman

Context. In the HI line profiles in the Leiden-Argentina-Bonn (LAB) all-sky database, we have found a population of very cold HI clouds. So far, the role of these clouds in the interstellar medium (ISM) has remained unclear. Aims. In this…

Astrophysics of Galaxies · Physics 2013-04-11 Urmas Haud

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…

We report on a population of absorption systems selected by the presence of very weak Mg II doublets. A sub-population of these systems are iron enriched and have near solar metallicities. This would indicated advanced stages (i.e. few Gyr)…

Astrophysics · Physics 2007-05-23 Chris Churchill , Jane Rigby , Jane Charlton

We report the first high-resolution (sub-arcminute) large-scale mapping $^{12}$CO and $^{13}$CO observations of the molecular clouds associated with the giant outer Galaxy HII region CTB~102 (KR 1). These observations were made using a…

Astrophysics of Galaxies · Physics 2019-05-08 Brandon Marshall , Sung-ju Kang , C. R. Kerton , Youngsik Kim , Minho Choi , Miju Kang

We present 3.7 arcsec (~0.05 pc) resolution 3.2 mm dust continuum observations from the IRAM PdBI, with the aim of studying the structure and fragmentation of the filamentary Infrared Dark Cloud G035.39-00.33. The continuum emission is…

Astrophysics of Galaxies · Physics 2016-08-16 J. D. Henshaw , P. Caselli , F. Fontani , I. Jimenez-Serra , J. C. Tan , S. N. Longmore , J. E. Pineda , R. J. Parker , A. T. Barnes

We confirm and discuss recently discovered cold HI clouds with column densities among the lowest ever detected. The column densities of Cold Neutral Medium (CNM) towards 3C286 and 3C287 are ~10^18 cm^-2, below an observational lower limit,…

Astrophysics · Physics 2009-11-11 Snezana Stanimirovic , Carl Heiles

Recent targeted studies of associated HI absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 J. R. Allison , E. M. Sadler , S. J. Curran , S. N. Reeves

The dense, cold regions where high-mass stars form are poorly characterised, yet they represent an ideal opportunity to learn more about the initial conditions of high-mass star formation (HMSF), since high-mass starless cores (HMSCs) lack…

Astrophysics of Galaxies · Physics 2016-08-02 S. Feng , H. Beuther , Q. Zhang , Th. Henning , H. Linz , S. Ragan , R. Smith

HI absorption studies yield information on both AGN feeding and feedback processes. This AGN activity interacts with the neutral gas in compact radio sources, which are believed to represent the young or recently re-triggered AGN…

Astrophysics of Galaxies · Physics 2017-02-01 M. Glowacki , J. R. Allison , E. M. Sadler , V. A. Moss , S. J. Curran , A. Musaeva , C. Deng , R. Parry , M. C. Sligo

Observations of extragalactic objects need to be corrected for Galactic absorption and this is often accomplished by using the measured 21 cm HI column. However, within the beam of the radio telescope there are variations in the HI column…

Astrophysics · Physics 2009-11-10 Joel N. Bregman , Megan C. Novicki , Jessica E. Krick , John S. Arabadjis

We estimate the evaporation timescale for spherical HI clouds consisting of the cold neutral medium surrounded by the warm neutral medium. We focus on clouds smaller than 1pc, which corresponds to tiny HI clouds recently discovered by Braun…

Astrophysics · Physics 2009-11-11 Masahiro Nagashima , Shu-ichiro Inutsuka , Hiroshi Koyama

Given the rarity of young O star candidates, compact HII regions embedded in dense molecular cores continue to serve as potential sites to peer into the details of high-mass star formation. To uncover the ionizing sources of the most…

Solar and Stellar Astrophysics · Physics 2015-06-16 J. M. C. Grave , M. S. N. Kumar , D. K. Ojha , G. Teixeira , G. Pace

Context. The derived physical parameters for young HII regions are normally determined assuming the emission region to be optically thin. However, this assumption is unlikely to hold for young HII regions such as hyper-compact HII(HCHII)…

We present a multiwavelength study of the ultra compact HII region associated with IRAS 20178+4046. This enables us to probe the different components associated with this massive star forming region. The radio emission from the ionized gas…

Astrophysics · Physics 2009-11-13 A. Tej , S. K. Ghosh , V. K. Kulkarni , D. K. Ojha , R. P. Verma , S. Vig

Recent studies have shown that both 21cm HI absorption and soft X-ray absorption serve as excellent tracers of the dense and dusty gas near the active nucleus of young radio galaxies, offering new insight into the physical nature of the…

Astrophysics of Galaxies · Physics 2022-01-05 Emily F. Kerrison , Vanessa A. Moss , Elaine M. Sadler , James R. Allison