中文
相关论文

相关论文: Tiny HI Clouds in the Local ISM

200 篇论文

We present a study of the small-scale structure of the interstellar medium in the Milky Way. We used HST STIS data to measure N(HI) in a pencil-beam toward 59 AGNs and compared the results with the values seen at 9 arcmin - 36 arcmin…

星系天体物理 · 物理学 2015-05-20 Bart P. Wakker , Felix J. Lockman , Jonathan M. Brown

We have analyzed sensitive high spatial resolution archival radio continuum data at 1.3, 2.0, 3.6 and 6.0 cm as well as the H2O maser molecular line data obtained using the Very Large Array (VLA) in its hybrid AB configuration toward the…

天体物理学 · 物理学 2009-11-13 Luis A. Zapata , Silvia Leurini , Karl M. Menten , Peter Schilke , Rainer Rolffs , Carolin Hieret

The redshifted 1420 MHz emission from the HI in unresolved damped Lyman-\alpha clouds at high z will appear as a background radiation in low frequency radio observations. This holds the possibility of a new tool for studying the universe at…

天体物理学 · 物理学 2009-10-31 Somnath Bharadwaj , Biman B. Nath , Shiv K. Sethi

Photoionization models frequently assume constant temperature or density within HII regions. We investigate this assumption by measuring the detailed temperature and density structures of four HII regions in the Large Magellanic Cloud and…

星系天体物理 · 物理学 2023-10-04 Yifei Jin , Ralph Sutherland , Lisa Kewley , David Nicholls

In an ongoing effort to identify and study high-mass protostellar candidates we have observed in various tracers a sample of 235 sources selected from the IRAS Point Source Catalog, mostly with dec < -30 deg, with the SEST antenna at…

We present deep 3.6 cm radio continuum observations of the HII region W40 obtained using the Very Large Array in its A and B configurations. We detect a total of 20 compact radio sources in a region of 4 x 4 arcmin, with 11 of them…

星系天体物理 · 物理学 2015-05-19 Luis F. Rodríguez , Steven A. Rodney , Bo Reipurth

We present maps of the 850 micron and 450 micron continuum emission seen towards a sample of 68 high-mass protostellar candidates with luminosities ranging from 10^2.5 to 10^5 solar luminosity. Most of these candidate high-mass stars are in…

天体物理学 · 物理学 2009-11-10 S. J. Williams , G. A. Fuller , T. K. Sridharan

An accurate estimate of the interstellar gas density distribution is crucial to understanding the interstellar medium (ISM) and Galactic cosmic rays (CRs). To comprehend the ISM and CRs in a local environment, a study of the diffuse…

高能天体物理现象 · 物理学 2020-02-26 T. Mizuno , S. Abdollahi , Y. Fukui , K. Hayashi , T. Koyama , A. Okumura , H. Tajima , H. Yamamoto

We present radio and infrared observations of 4 hyper-compact HII regions and 4 ultra-compact HII regions in the southern Galactic plane. These objects were selected from a blind survey for UCHII regions using data from two new radio…

星系天体物理 · 物理学 2015-05-18 Tara Murphy , Martin Cohen , Ronald D. Ekers , Anne J. Green , Robin Wark , Vanessa Moss

Growing evidence supports the suggestion that the compact high-velocity clouds of HI (CHVCs) are located throughout the Local Group and continue to fuel galactic evolution. Recent distance estimates to individual objects lie in the range…

天体物理学 · 物理学 2009-10-31 Robert Braun , W. Butler Burton

We are addressing the sites of isolated low mass star formation in the solar neighbourhood, i.e. small cloud cores within one kiloparsec. We aim at determining the physical parameters of the cores, i.e., temperature, volume density, column…

星系天体物理 · 物理学 2017-03-21 Bengt Larsson , René Liseau

The heliosphere serves as a probe of interstellar material (ISM) close to the Sun. Measurements of ISM inside and outside of the heliosphere show that we reside in typical warm partially ionized ISM that can be successfully modeled using…

天体物理学 · 物理学 2007-05-23 P. C. Frisch

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 a SCUBA submillimetre (450 & 850 micron) survey of the environment of 105 IRAS point sources, selected from the Wood & Churchwell (1989a) and Kurtz, Churchwell & Wood (1994) radio ultracompact (UC) HII region surveys. We detected…

天体物理学 · 物理学 2009-11-11 M. A. Thompson , J. Hatchell , A. J. Walsh , G. H. Macdonald , T. J. Millar

Over the course of its motion through the Galaxy, our solar system has encountered many interstellar environments of varying characteristics. Interstellar medium (ISM) density variations spanning seven orders of magnitude are commonly seen…

太阳与恒星天体物理 · 物理学 2015-06-16 Katherine Wyman , Seth Redfield

Infrared-dark clouds (IRDCs) harbor the early phases of cluster and high-mass star formation and are comprised of cold (~20 K), dense (n > 10$^4$ cm$^{-3}$) gas. The spectral energy distribution (SED) of IRDCs is dominated by the…

星系天体物理 · 物理学 2015-06-17 Sarah E. Ragan , Thomas Henning , Henrik Beuther

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…

We present and discuss new high-sensitivity and resolution radio-continuum images of the Small Magellanic Cloud (SMC) at lambda=20 cm (nu=1.4 GHz). The new images were created by merging 20-cm radiocontinuum archival data, from the…

宇宙学与河外天体物理 · 物理学 2015-05-28 G. F. Wong , M. D. Filipović , E. J. Crawford , A. De Horta , T. Galvin , D. Drasković , J. L. Payne

We present a comprehensive survey of CII* absorption detections toward stars within 100 pc in order to measure the distribution of electron densities present in the local interstellar medium (LISM). Using high spectral resolution…

天体物理学 · 物理学 2009-11-13 Seth Redfield , Ross E. Falcon

Context. The largest grains (0.5-1 micron) in the interstellar size distribution are efficient in scattering near- and mid-infrared radiation. These wavelengths are therefore particularly well suited to probe the still uncertain high-end of…

星系天体物理 · 物理学 2015-06-17 M. Andersen , J. Steinacker , W-F. Thi , L. Pagani , A. Bacmann , R. Paladini