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Motivated by recent observational searches of sub-structure in starless molecular cloud cores, we investigate the evolution of density perturbations on scales smaller than the Jeans length embedded in contracting isothermal clouds, adopting…

Solar and Stellar Astrophysics · Physics 2017-12-20 C. Toci , D. Galli , A. Verdini , L. Del Zanna , S. Landi

We combine previously published interferometric and single-dish data of relatively nearby massive dense cores that are actively forming stars to test whether their `fragmentation level' is controlled by turbulent or thermal support. We find…

Observations of prestellar cores in star-forming filaments show two distinct morphologies. While molecular line measurements often show broad cores, submillimeter continuum observations predominantly display pinched cores compared to the…

Astrophysics of Galaxies · Physics 2018-08-15 Stefan Heigl , Matthias Gritschneder , Andreas Burkert

We present new NH3 (1,1), (2,2), and (4,4) observations from the Karl G. Jansky Very Large Array (VLA) compiled with work in the literature to explore the range of conditions observed in young, massive star-forming regions. To sample the…

Astrophysics of Galaxies · Physics 2015-06-19 Cara Battersby , Adam Ginsburg , John Bally , Steve Longmore , Miranda Dunham , Jeremy Darling

In this study we investigate the formation and properties of prestellar and protostellar cores using hydrodynamic, self-gravitating Adaptive Mesh Refinement simulations, comparing the cases where turbulence is continually driven and where…

Astrophysics · Physics 2009-11-13 S. S. R. Offner , M. R. Krumholz , R. I. Klein , C. F. McKee

To characterize the initial conditions for intermediate- to high-mass star formation, we observed two Infrared Dark Clouds (IRDCs) that remain absorption features up to 70mum wavelength, with the PdBI in the 3.23mm dust continuum as well as…

Solar and Stellar Astrophysics · Physics 2015-05-13 Henrik Beuther , Thomas Henning

Motivated by the observation of extended stellar cores in dark matter (DM) dominated dwarf galaxies, this study investigates a simple mechanism by which stellar cores can form as a result of DM halo expansion. Several non-CDM models predict…

Astrophysics of Galaxies · Physics 2025-10-22 Jorge Sanchez Almeida , Angel R. Plastino , Ignacio Trujillo

Dusty starless cores play an important role in regulating the initial phases of the formation of stars and planets. In their interiors, dust grains coagulate and ice mantles form, thereby changing the millimeter emissivities and hence the…

Previous studies show that the physical structures and kinematics of a region depend significantly on the ionisation fraction. In this paper, we extend our previous studies of the effect of ionisation fractions on star formation to clouds…

Solar and Stellar Astrophysics · Physics 2017-05-03 Nicole D. Bailey , Shantanu Basu , Paola Caselli

Aims: Understanding the fragmentation and collapse properties of the dense gas during the onset of high-mass star formation. Methods: We observed the massive (~800M_sun) starless gas clump IRDC18310-4 with the Plateau de Bure Interferometer…

Astrophysics of Galaxies · Physics 2015-09-23 H. Beuther , Th. Henning , H. Linz , S. Feng , S. E. Ragan , R. J. Smith , S. Bihr , T. Sakai , R. Kuiper

We use numerical hydrodynamic simulations to investigate prestellar core formation in the dynamic environment of giant molecular clouds, focusing on planar post-shock layers produced by colliding turbulent flows. A key goal is to test how…

Solar and Stellar Astrophysics · Physics 2015-05-27 Hao Gong , Eve C. Ostriker

Following an approach initially outlined by McKee & Holliman, we investigate the structure and stability of dense, starless molecular cloud cores. We model those as spherical clouds in hydrostatic equilibrium and supported against gravity…

Astrophysics · Physics 2007-05-23 J. Kauffmann , F. Bertoldi

The isothermal gravitational collapse and fragmentation of a region within a molecular cloud and the subsequent formation of a protostellar cluster is investigated numerically. The clump mass spectrum which forms during the fragmentation…

Astrophysics · Physics 2009-10-30 Ralf S. Klessen , Andreas Burkert , Matthew R. Bate

We report ALMA Band 6 continuum observations of 2000 AU resolution toward four massive molecular clouds in the Central Molecular Zone of the Galaxy. To study gas fragmentation, we use the dendrogram method to identify cores as traced by the…

Due to the gas rich environments of early circumstellar disks, the gravitational collapse of cool, dense regions of the disk form fragments largely composed of gas. During formation, disk fragments may attain increased metallicities as they…

Earth and Planetary Astrophysics · Physics 2019-08-26 Hans Baehr , Hubert Klahr

Context. Traditionally, supersonic turbulence is considered to be one of the most likely mechanisms to slow down the gravitational collapse in dense clumps, thereby enabling the formation of massive stars. However, several recent studies…

In order to study the fragmentation of massive dense cores, which constitute the cluster cradles, we observed with the PdBI in the most extended configuration the continuum at 1.3 mm and the CO(2-1) emission of four massive cores. We detect…

We review recent advances in the analytical and numerical modeling of the star formation rate in molecular clouds and discuss the available observational constraints. We focus on molecular clouds as the fundamental star formation sites,…

The interstellar medium is characterised by an intricate filamentary network which exhibits complex structures. These show a variety of different shapes (e.g. junctions, rings, etc.) deviating strongly from the usually assumed cylindrical…

Astrophysics of Galaxies · Physics 2021-07-14 Elena Hoemann , Stefan Heigl , Andreas Burkert

We present 850~$\mu$m linear polarization and C$^{18}$O~(3-2) and $^{13}$CO~(3-2) molecular line observations toward the filaments (F13 and F13S) in the Cocoon Nebula (IC~5146) using the JCMT POL-2 and HARP instruments. F13 and F13S are…

Astrophysics of Galaxies · Physics 2024-05-28 Eun Jung Chung , Chang Won Lee , Shinyoung Kim , Mario Tafalla , Hyunju Yoo , Jungyeon Cho , Woojin Kwon