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相关论文: The Density and Temperature of Molecular Clouds in…

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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

NGC 2024, a sites of massive star formation, have complex internal structures caused by cal heating by young stars, outflows, and stellar winds. These complex cloud structures lead to intricate emission line shapes. The goal of this paper…

To investigate how molecular clouds react to different environmental conditions at a galactic scale, we present a catalogue of giant molecular clouds resolved down to masses of $\sim 10$~M$_{\odot}$ from a simulation of the entire disc of…

[Abridged] Do some environments favor efficient conversion of molecular gas into stars? To answer this, we need to be able to estimate the H2 mass. Traditionally, this is done using CO and a few assumptions but the Herschel observations in…

Numerical simulations have explored the possibility to form molecular clouds through either a quasi-static, self-gravitating mechanism or the collision of gas streams or lower-density clouds. They also quantitatively predict the…

Neither HI nor CO emission can reveal a significant quantity of so-called dark gas in the interstellar medium (ISM). It is considered that CO-dark molecular gas (DMG), the molecular gas with no or weak CO emission, dominates dark gas. We…

星系天体物理 · 物理学 2016-09-14 Ningyu Tang , Di Li , Carl Heiles , Shen Wang , Zhichen Pan , Jun-Jie Wang

Young HII regions are an important site to study O star formation based on distributions of ionized and molecular gas. We revealed that two molecular clouds at $\sim 48$ km s$^{-1}$ and $\sim 53$ km s$^{-1}$ are associated with the HII…

We present results of a ^{12}CO J = 3-2 survey of 125 nearby galaxies obtained with the 10-m Heinrich-Hertz-Telescope, with the aim to characterize the properties of warm and dense molecular gas in a large variety of environments. With an…

宇宙学与河外天体物理 · 物理学 2015-05-20 Rui-Qing Mao , Andreas Schulz , Christian Henkel , Rainer Mauersberger , Dirk Muders , Dihn-V-Trung

Giant molecular clouds contain supersonic turbulence that can locally heat small fractions of gas to over 100 K. We run shock models for low-velocity, C-type shocks propagating into gas with densities between 10^3 and 10^5 cm^(-3) and find…

星系天体物理 · 物理学 2016-08-23 A. Pon , M. J. Kaufman , D. Johnstone , P. Caselli , F. Fontani , M. J. Butler , I. Jiménez-Serra , A. Palau , J. C. Tan

We used the KOSMA 3m telescope to map the core 7'x5' of the Galactic massive star forming region W3Main in the two fine structure lines of atomic carbon and four mid-J transitions of CO and 13CO. The maps are centered on the luminous…

天体物理学 · 物理学 2009-11-10 C. Kramer , H. Jakob , B. Mookerjea , N. Schneider , M. Bruell , J. Stutzki

We mapped the kinetic temperature structure of the Orion molecular cloud 1 with para-H2CO(303-202, 322-221, and 321-220) using the APEX 12m telescope. This is compared with the temperatures derived from the ratio of the NH3(2,2)/(1,1)…

We present the results of ALMA observations in $^{12}$CO($J=2-1$), $^{13}$CO($J=2-1$), and C$^{18}$O($J=2-1$) lines and 1.3 mm continuum emission toward a massive ($\sim 10^6 M_{\odot}$) giant molecular cloud associated with the giant H II…

We present an analysis of multi-wavelength observations of an area of 0.27 deg x 0.27 deg around the Galactic HII region G18.88-0.49, which is powered by an O-type star (age ~10^5 years). The Herschel column density map reveals a shell-like…

星系天体物理 · 物理学 2020-11-04 L. K. Dewangan , D. K. Ojha , Saurabh Sharma , S. del Palacio , N. K. Bhadari , A. Das

We present J=2-1, J=3-2, J=4-3 12CO and 492 GHz [CI] maps as well as J=2-1 and J=3-2 13CO measurements of the central regions in the nearby Sc galaxies IC 342 and Maffei 2. In both galaxies, the distribution of CO and [CI] is strongly…

天体物理学 · 物理学 2009-11-07 F. P. Israel , F. Baas

Revealing the 3D dynamics of HII regions and their associated molecular clouds is important for understanding the longstanding problem as to how stellar feedback affects the density structure and kinematics of the interstellar medium. We…

We present synthetic Hi and CO observations of a simulation of decaying turbulence in the thermally bistable neutral medium. We first present the simulation, with clouds initially consisting of clustered clumps. Self-gravity causes these…

星系天体物理 · 物理学 2015-08-06 Jonathan S. Heiner , Enrique Vázquez-Semadeni , Javier Ballesteros-Paredes

We present the results of an exhaustive study of the ionized gas in NGC 588, a giant H II region in the nearby spiral galaxy M33. This analysis uses a high number of diagnostics in the optical and infrared ranges. Four temperature…

天体物理学 · 物理学 2016-08-30 L. Jamet , G. Stasinska , E. Perez , R. M. Gonzalez Delgado , J. M. Vilchez

A population of discrete HI clouds in the halo of the inner Galaxy has been discovered in 21cm observations made with the Green Bank Telescope. The halo clouds are seen up to 1.5 kpc from the Galactic plane at many longitudes. Their…

天体物理学 · 物理学 2009-11-07 Felix J. Lockman