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We study the formation and early evolution of star clusters that have a wide range of masses and background cloud mass surface densities, $\Sigma_{\rm cloud}$, which help set the initial sizes, densities, and velocity dispersions of the…

星系天体物理 · 物理学 2023-06-08 Juan P. Farias , Jonathan C. Tan

Spatially resolved HI studies of dwarf galaxies have provided a wealth of precision data. However these high-quality, resolved observations are only possible for handful of dwarf galaxies in the Local Volume. Future HI surveys are unlikely…

星系天体物理 · 物理学 2018-06-06 A. Lopez-Sanchez , C. D. P. Lagos , T. Young , H. Jerjen

We investigate cloud-cloud collisions, and GMC evolution, in hydrodynamic simulations of isolated galaxies. The simulations include heating and cooling of the ISM, self--gravity and stellar feedback. Over timescales $<5$ Myr most clouds…

星系天体物理 · 物理学 2015-06-23 C. L. Dobbs , J. E. Pringle , A. Duarte-Cabral

An analysis of large-area CO J=3-2 maps from the James Clerk Maxwell Telescope for 12 nearby spiral galaxies reveals low velocity dispersions in the molecular component of the interstellar medium. The three lowest luminosity galaxies show a…

We present a scenario for the formation of disks which explains not only the properties of normal galaxies, but the properties of the population of low surface brightness galaxies (LSBs) as well. We use a gravitationally self-consistent…

天体物理学 · 物理学 2009-10-28 J. J. Dalcanton , D. N. Spergel , F J Summers

Star formation in galaxies is a complex phenomenon occurring on a very wide range of scales, and molecular clouds are at the heart of this process. The formation of these structures and the subsequent collapse of the gas within them to form…

星系天体物理 · 物理学 2025-12-22 Noé Brucy , Enrique Vázquez-Semadeni , Tine Colman , Jérémy Fensch , Ralf S. Klessen

In this paper we investigate scaling relations between star formation rates and molecular gas masses for both local Galactic clouds and a sample of external galaxies. We specifically consider relations between the star formation rates and…

星系天体物理 · 物理学 2015-06-03 Charles J. Lada , Jan Forbrich , Marco Lombardi , Joao F. Alves

We use the marginal stability condition for galactic disks and the stellar velocity dispersion data published by different authors to place upper limits on the disk local surface density at two radial scalelengths $R=2h$. Extrapolating…

宇宙学与河外天体物理 · 物理学 2015-05-20 A. V. Zasov , A. V. Khoperskov , A. S. Saburova

Star-forming regions presenting a density gradient experience a higher star formation rate than if they were of uniform density. We refer to the ratio between the star formation rate of a spherical centrally-concentrated gas clump and the…

星系天体物理 · 物理学 2020-01-08 Genevieve Parmentier

Stars form in cold molecular clouds. However, molecular gas is difficult to observe because the most abundant molecule (H2) lacks a permanent dipole moment. Rotational transitions of CO are often used as a tracer of H2, but CO is much less…

We explore the Schmidt-Kennicutt (SK) relations and the star formation efficiency per free-fall time ($\epsilon_{\rm ff}$), mirroring observational studies, in numerical simulations of filamentary molecular clouds undergoing gravitational…

It has been known for more than 30 years that star formation in giant molecular clouds (GMCs) is slow, in the sense that only ~1% of the gas forms stars every free-fall time. This result is entirely independent of any particular model of…

天体物理学 · 物理学 2008-11-26 Mark R. Krumholz , Jonathan C. Tan

Young massive clusters (YMCs) are recently formed astronomical objects with unusually high star formation rates. We propose the collision of giant molecular clouds (GMCs) as a likely formation mechanism of YMCs, consistent with the YMC…

星系天体物理 · 物理学 2020-09-30 K. Y. Liow , C. L. Dobbs

Collisions between giant molecular clouds (GMCs) have been proposed as a mechanism to trigger massive star and star cluster formation. To investigate the astrochemical signatures of such collisions, we carry out 3D magnetohydrodynamics…

星系天体物理 · 物理学 2023-08-24 Chia-Jung Hsu , Jonathan C. Tan , Jonathan Holdship , Duo , Xu , Serena Viti , Benjamin Wu , Brandt Gaches

We investigated the evolution of interacting disk galaxies using high-resolution $N$-body/SPH simulations, taking into account the multiphase nature of the interstellar medium (ISM). In our high-resolution simulations, a large-scale…

The outer Galaxy presents an optimal setting for investigating molecular clouds and star formation in environments with low metallicity. A total of 72 Galactic edge clouds were surveyed using the CO\,(2--1) line with the IRAM\,30\,m…

We estimate the star formation efficiency per gravitational free fall time, $\epsilon_{\rm ff}$, from observations of nearby galaxies with resolution matched to the typical size of a Giant Molecular Cloud. This quantity, $\epsilon_{\rm…

In order to understand what controls the star formation process in luminous starburst mergers (e.g., NGC 6240, Arp 220, and so on), we investigate observational properties of two samples of high-luminosity starburst galaxies mapped in…

天体物理学 · 物理学 2009-10-31 Yoshiaki Taniguchi , Youichi Ohyama

We explore the relationship between stellar surface density and gas surface density (the star-gas or S-G correlation) in a 20,000 M$_{\odot}$ simulation from the STAR FORmation in Gaseous Environments (STARFORGE) Project. We create…

星系天体物理 · 物理学 2023-10-19 Samuel Millstone , Robert Gutermuth , Stella S. R. Offner , Riwaj Pokhrel , Michael Y. Grudić

In this review, I present the case for how massive stars may form through stellar collisions. This mechanism requires very high stellar densities, up to 4 orders of magnitude higher than are observed in the cores of dense young clusters. In…

天体物理学 · 物理学 2007-05-23 Ian A. Bonnell