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We present the dynamics study toward the G326.611+0.811 (G326) hub-filament-system (HFS) cloud using the new APEX observations of both $^{13}$CO and C$^{18}$O (J = 2-1). The G326 HFS cloud constitutes a central hub and at least four…

With new THz maps that cover an area of ~3.3x2.1 pc^2 we probe the spatial distribution and association of the ionized, neutral and molecular gas components in the M17 SW nebula. We used the dual band receiver GREAT on board the SOFIA…

星系天体物理 · 物理学 2015-06-04 J. P. Perez-Beaupuits , H. Wiesemeyer , V. Ossenkopf , J. Stutzki , R. Guesten , R. Simon , H. -W. Huebers , O. Ricken

The increased sensitivity and spectral resolution of observed spectra towards the pre-stellar core L1544 are challenging the current physical and chemical models. With the aim of further constraining the structure of L1544 as well as…

星系天体物理 · 物理学 2025-08-29 J. Ferrer Asensio , S. S. Jensen , S. Spezzano , P. Caselli , F. O. Alves , O. Sipilä , E. Redaelli

Understanding of clouds is instrumental in interpreting current and future spectroscopic observations of exoplanets. Modelling clouds consistently is complex, since it involves many facets of chemistry, nucleation theory, condensation…

地球与行星天体物理 · 物理学 2019-02-13 Chris W. Ormel , Michiel Min

Recent observations suggest the presence of clouds in exoplanet atmospheres but have also shown that certain chemical species in the upper atmosphere might not be in chemical equilibrium. The goal of this work is to calculate the two main…

地球与行星天体物理 · 物理学 2023-11-07 Sven Kiefer , Helena Lecoq-Molinos , Christiane Helling , Nidhi Bangera , Leen Decin

We investigate non-linear scaling relations for two-dimensional gravitational collapse in an expanding background using a 2D TreePM code and study the strongly non-linear regime ($\bar\xi \leq 200$) for power law models. Evolution of these…

天体物理学 · 物理学 2007-05-23 S. Ray , J. S. Bagla , T. Padmanabhan

We perform a molecular (CO and CN) line observation using IRAM 30m telescope toward two small regions near the western edge of supernova remnant (SNR) W50/SS433. CO observation reveals spatial correspondence of two molecular clumps at the…

高能天体物理现象 · 物理学 2020-04-21 Qian-Cheng Liu , Yang Chen , Ping Zhou , Xiao Zhang , Bing Jiang

We present a wide-field $(60\arcmin \times 30\arcmin)$ study of a dense region within the Polaris Flare, hereafter referred to as the `Polaris molecular cloud', using $^{12}$CO, $^{13}$CO, and C$^{18}$O ($J=1-0$) observations at $20\arcsec$…

星系天体物理 · 物理学 2025-02-18 Tomomi Shimoikura , Kazuhito Dobashi , Fumitaka Nakamura , Kotomi Taniguchi

We present an analysis comparing the properties of 45 giant molecular clouds (GMCs) in M33 and the atomic hydrogen (HI) with which they are associated. High-resolution VLA observations are used to measure the properties of HI in the…

宇宙学与河外天体物理 · 物理学 2015-05-27 N. Imara , F. Bigiel , L. Blitz

Global Climate Models (GCM) are very useful tools to study theoretically the general dynamics and specific phenomena in planetary atmospheres. In the case of Venus, several GCMs succeeded in reproducing the atmosphere's superrotation and…

地球与行星天体物理 · 物理学 2024-02-07 I. Garate-Lopez , Sébastien Lebonnois

The interstellar region within the few central parsecs around the super-massive black hole, Sgr A* at the very Galactic center is composed by a number of overlapping molecular structures which are subject to one of the most hostile physical…

星系天体物理 · 物理学 2015-06-03 S. Martín , J. Martín-Pintado , M. Montero-Castaño , P. T. P. Ho , R. Blundell

We present N-PDFs of 29 Galactic regions obtained from Herschel imaging at high angular resolution, covering diffuse and quiescent clouds, and those showing low-, intermediate-, and high-mass star formation (SF), and characterize the cloud…

When a self-gravitating spherical gas cloud collapses or accretes onto a central mass, the inner region of the cloud develops a density profile $\rho\propto r^{-3/2}$ and the velocity approaches free-fall. We show that in this region,…

天体物理学 · 物理学 2009-10-31 Dong Lai , Peter Goldreich

Complex A is a high-velocity cloud that is traversing through the Galactic halo toward the Milky Way's disk. We combine both new and archival Green Bank Telescope observations to construct a spectroscopically resolved HI~21-cm map of this…

In this article we extend the study performed in our previous article on the collapse of primordial objects. We here analyze the behavior of the physical parameters for clouds ranging from $10^7M_\odot$ to $10^{15}M_\odot$. We studied the…

天体物理学 · 物理学 2009-10-30 S. R. Oliveira , O. D. Miranda , J. C. N. de Araujo , R. Opher

There are relatively few H2CO mappings of large-area giant molecular cloud (GMCs). H2CO absorption lines are good tracers for low-temperature molecular clouds towards star formation regions. Thus, the aim of the study was to identify H2CO…

星系天体物理 · 物理学 2011-08-22 Chuan Peng Zhang , Jarken Esimbek , Jian Jun Zhou , Gang Wu , Zhi Mao Du

We develop a detailed chemical model for the starless cores of strongly magnetized molecular clouds, with the ambipolar diffusion-driven dynamic evolution of the clouds coupled to the chemistry through ion abundances. We concentrate on two…

天体物理学 · 物理学 2009-11-07 Zhi-Yun Li , V. I. Shematovich , D. S. Wiebe , B. M. Shustov

We simulate fragmentation and gravitational collapse of cold, magnetized molecular clouds. We explore the nonlinear development of an instability mediated by ambipolar diffusion, in which the collapse rate is intermediate to fast…

天体物理学 · 物理学 2009-10-31 R. Indebetouw , E. G. Zweibel

Six examples of the compact, isolated high-velocity HI clouds (CHVCs) identified by Braun and Burton (1999) have been imaged with the WSRT. The 65 confirmed objects in this class define a dynamically cold system, with a global minimum for…

天体物理学 · 物理学 2007-05-23 Robert Braun , Butler Burton

We mapped a 13 by 22 pc region in emission from 492 GHz [C I] and, for the first time, 551 GHz ^{13}CO(5-4) in the giant molecular cloud M17SW, using the Submillimeter Wave Astronomy Satellite. The morphologies of the [C I] and ^{13}CO…