English
Related papers

Related papers: W49A North - Global or Local or No Collapse?

200 papers

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…

Astrophysics of Galaxies · Physics 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…

Astrophysics of Galaxies · Physics 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…

Earth and Planetary Astrophysics · Physics 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…

Earth and Planetary Astrophysics · Physics 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…

Astrophysics · Physics 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…

High Energy Astrophysical Phenomena · Physics 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 $20\arcsec$…

Astrophysics of Galaxies · Physics 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…

Cosmology and Nongalactic Astrophysics · Physics 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…

Earth and Planetary Astrophysics · Physics 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…

Astrophysics of Galaxies · Physics 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,…

Astrophysics · Physics 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…

Astrophysics · Physics 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…

Astrophysics of Galaxies · Physics 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…

Astrophysics · Physics 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…

Astrophysics · Physics 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…

Astrophysics · Physics 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…