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相关论文: Tiny HI Clouds in the Local ISM

200 篇论文

High-resolution JWST-MIRI images now allow us to resolve in great detail the multi-scale nature of the emission in nearby star-forming galaxies, from compact star-forming regions to large-scale diffuse emission, giving new insights into…

{We report the discovery of 20 new dwarf galaxies in the Local Volume identified as optical counterparts to the Five-hundred-meter Aperture Spherical radio Telescope (FAST) All Sky HI Survey (FASHI) sources. The galaxies have a median…

星系天体物理 · 物理学 2024-05-01 Igor D. Karachentsev , Valentina E. Karachentseva , Serafim S. Kaisin , Chuan-Peng Zhang

This study uses archival high frequency continuum data to expand the search for Hypercompact HII regions and determine the conditions at which they appear, as this stage high mass star formation is short-lived and rare. We use 23 GHz…

We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is…

宇宙学与河外天体物理 · 物理学 2014-12-01 J. Y. Koay , J. -P. Macquart

New 21 cm HI observations have revealed a giant HI cloud in the Galactic plane that has unusual properties. It is quite well defined, about 150 pc in diameter at a distance of 5 kpc, and contains as much as 100,000 Solar Masses of atomic…

天体物理学 · 物理学 2009-11-06 Anthony H. Minter , Felix J. Lockman , Glen I. Langston , Jennifer A. Lockman

We have discovered two compact sources of shocked H2 2.12-micron emission coincident with Mol 160 (IRAS 23385+6053), a massive star-forming core thought to be a precursor to an ultracompact HII region. The 2.12-micron sources lie within 2"…

星系天体物理 · 物理学 2015-06-03 Grace Wolf-Chase , Michael Smutko

As a complement to the HyGAL Stratospheric Observatory for Infrared Astronomy Legacy Program, we report the results of a ground-based absorption line survey of simple molecules in diffuse and translucent Galactic clouds. Using the Institut…

At low radio frequencies (< 100 MHz), classical HII regions may become optically thick (optical depth > 1) and can be observed as discrete absorption regions against the Galactic nonthermal background emission created by Galactic cosmic ray…

天体物理学 · 物理学 2008-11-26 Michael E. Nord , P. A. Henning , R. J. Rand , T. Joseph W. Lazio , Namir E. Kassim

Very sensitive 21cm HI measurements have been made at several locations around the Local Group galaxy M31 using the Green Bank Telescope (GBT) at an angular resolution of 9.1', with a 5$\sigma$ detection level of $\rm{N_{HI} = 3.9 \times…

星系天体物理 · 物理学 2016-01-27 Spencer A. Wolfe , Felix J. Lockman , D. J. Pisano

The star-forming activity in the HII region RCW 42 is investigated using multiple wavebands, from near-infrared to radio wavelengths. Located at a distance of 5.8 kpc, this southern region has a bolometric luminosity of 1.8 $\times$ 10$^6$…

星系天体物理 · 物理学 2022-08-17 Vipin Kumar , S. Vig , V. S. Veena , S. Mohan , S. K. Ghosh , A. Tej , D. K. Ojha

We present 52-93 micron spectra, obtained with the Spitzer Space Telescope, of luminous compact far-IR sources in the SMC. These comprise 9 Young Stellar Objects (YSOs), the compact HII region N81 and a similar object within N84, and two…

星系天体物理 · 物理学 2015-05-18 Jacco Th. van Loon , Joana M. Oliveira , Karl D. Gordon , G. C. Sloan , C. W. Engelbracht

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

We have applied the unsharp-masking technique to the 24 $\mu$m image of the Small Magellanic Cloud (SMC), obtained with the Spitzer Space Telescope, to search for high-extinction regions. This technique has been used to locate very dense…

Optical depth variations in the Galactic neutral interstellar medium (ISM) with spatial scales from hundreds to thousands of astronomical units have been observed through HI absorption against pulsars and continuum sources, while extremely…

Infrared dark clouds (IRDCs) are potential hosts of the elusive early phases of high-mass star formation (HMSF). Here we conduct an in-depth analysis of the fragmentation properties of a sample of 10 IRDCs, which have been highlighted as…

In this study, we explore the impact of inhomogeneities in the spatial distribution of interstellar dust on spatial scales of $\le1$ au caused by ion shadowing forces on the optical properties of diffuse interstellar medium (ISM) as well as…

星系天体物理 · 物理学 2020-05-27 Andrei B. Ostrovskii , S. Yu. Parfenov , A. I. Vasyunin , A. V. Ivlev , V. A. Sokolova

The southern Galactic high mass star-forming region, G351.6-1.3, is a HII region-molecular cloud complex with a luminosity of 2.0 x 10^5 L_sun, located at a distance of 2.4 kpc. In this paper, we focus on the investigation of the associated…

星系天体物理 · 物理学 2015-06-19 S. Vig , S. K. Ghosh , D. K. Ojha , R. P. Verma , M. Tamura

We present Giant Metrewave Radio Telescope 21-cm HI observations towards a sample of compact radio sources behind galaxy groups, to search for cool HI. The results -- from high dynamic range spectra for 8 lines-of-sight through 7 galaxy…

天体物理学 · 物理学 2014-10-13 D. A. Green , M. S. Clemens , P. Alexander , H. Cullen , B. Nikolic

We derive infrared and radio flux densities of all ~1000 known Galactic HII regions in the Galactic longitude range 17.5 < l < 65 degree. Our sample comes from the Wide-Field Infrared Survey Explorer (WISE) catalog of Galactic \hii regions…

星系天体物理 · 物理学 2017-09-06 Z. Makai , L. D. Anderson , J. L. Mascoop , B. Johnstone

We have detected over 400 HI clouds in the lower halo of the Galaxy within the pilot region of the Galactic All-Sky Survey (GASS), a region of the fourth quadrant that spans 18 degrees in longitude, 40 degrees in latitude and is centered on…