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Star formation is one of the key factors that shapes galaxies. This process is relatively well understood from both simulations and observations on a small "local" scale of individual giant molecular clouds and also on a "global"…

Astrophysics of Galaxies · Physics 2020-07-15 Charles Aouad , Philip James , Igor Chilingarian

The degree to which the properties of protostars are affected by environment remains an open question. To investigate this, we look at the Orion A and B molecular clouds, home to most of the protostars within 500 pc. At ~400 pc, Orion is…

The current study was developed to provide a database of relatively simple numerical simulations of protostellar collapse, as a template library for observations of cores and very young protostars, and for researchers who wish to test their…

Solar and Stellar Astrophysics · Physics 2018-08-08 Neil Vaytet , Troels Haugbølle

We propose a novel method of determination of the dust particle spatial distribution in dust clouds that form in three-dimensional (3D) complex plasmas under microgravity conditions. The method utilizes the data obtained during the 3D…

The Schmidt law (SF law) in the Milky Way was investigated using 3D distribution maps of HII regions, HI and molecular (\Htwo) gases with spatial resolutions of $\sim 1$ kpc in the Galactic plane and a few tens of pc in the vertical…

Astrophysics of Galaxies · Physics 2017-02-01 Yoshiaki Sofue , Hiroyuki Nakanishi

Several studies have reported a nearly linear correlation between the molecular gas and star formation rate surface density, the so-called Kennicutt-Schmidt (KS) law. We aim to retrieve the KS relation for a sample of four star-forming…

We extend and investigate the spheroidal model of interstellar dust grains used to simultaneously interpret the observed interstellar extinction and polarization curves. We compare our model with similar models recently suggested by other…

Astrophysics of Galaxies · Physics 2015-05-14 H. K. Das , N. V. Voshchinnikov , V. B. Il'in

The distributions of normal matter and of dark matter in the Galaxy are coupled to each other as they both move in the common gravitational potential. In order to fully exploit this interplay and to derive the various properties of dark…

Astrophysics of Galaxies · Physics 2013-12-16 Benjamin Burch , Ramanath Cowsik

Many recent models consider the structure of individual interstellar medium (ISM) clouds as a way to explain observations of large parts of galaxies. To compare such models to observations, one must understand how to translate between…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Adam K. Leroy , Cheoljong Lee , Andreas Schruba , Alberto Bolatto , Annie Hughes , Jerome Pety , Karin Sandstrom , Eva Schinnerer , Fabian Walter

To study the interaction of star-formation and turbulent molecular cloud structuring, we analyse numerical models and observations of self-gravitating clouds using the Delta-variance as statistical measure for structural characteristics. In…

Astrophysics · Physics 2009-11-07 Volker Ossenkopf , Ralf Klessen , Fabian Heitsch

Context. The impact of stellar feedback on the Kennicutt-Schmidt law (KS law), which relates star formation rate (SFR) to surface gas density, is a topic of ongoing debate. The interpretation of individual cloud observations is challenging…

Astrophysics of Galaxies · Physics 2023-12-01 Paolo Suin , Annie Zavagno , Tine Colman , Patrick Hennebelle , Antoine Verliat , Delphine Russeil

Spatial association of clumps from different tracers turns out to be a valuable tool to determine the physical properties of molecular clouds. It provides a reliable estimate for the $X$-factors, serves to trace the density of clumps seen…

Astrophysics of Galaxies · Physics 2018-02-14 Todor V. Veltchev , Volker Ossenkopf-Okada , Orlin Stanchev , Nicola Schneider , Sava Donkov , Ralf S. Klessen

The approach to model composite interstellar dust grains, using the exact solution to the light scattering problem for multi-layered spheres as suggested by Voshchinnikov & Mathis (1999), is further developed. Heterogeneous scatteres are…

Astrophysics · Physics 2007-05-23 N. V. Voshchinnikov , V. B. Il'in , Th. Henning , D. N. Dubkova

We performed a correlation analysis between the brightness temperature of the CO line and number density of HII regions in the longitude--velocity diagram (LVD) of the Milky Way in order to investigate the volumetric star-formation law. We…

Astrophysics of Galaxies · Physics 2024-03-05 Yoshiaki Sofue

For precision cosmological studies it is important to know the local properties of the reference point from which we observe the Universe. Particularly for the determination of the Hubble constant with low-redshift distance indicators, the…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-25 Hans Boehringer , Gayoung Chon , Chris A. Collins

The Gaia data give us an unprecedented view to the 3-dimensional (3D) structure of molecular clouds in the Solar neighbourhood. We study how the projected areas and masses of clouds, and consequently the Kennicutt-Schmidt relation…

Astrophysics of Galaxies · Physics 2022-03-14 Jouni Kainulainen , Sara Rezaei Kh. , Andri Spilker , Jan Orkisz

There is currently no accepted theoretical framework for the formation of the most massive stars, and the manner in which protostars continue to accrete and grow in mass beyond \sim10Msun is still a controversial topic. In this study we use…

Context. In order to understand the evolution of molecular clouds it is important to identify the departures from self-similarity associated with the scales of self-gravity and the driving of turbulence. Aims. A method is described based on…

Astrophysics · Physics 2009-11-11 M. Gustafsson , J. L. Lemaire , D. Field

We present a catalogue of molecular cloud cores drawn from high latitude, medium opacity clouds, using the all-sky IRAS Sky Survey Atlas (ISSA) images at 60 and 100~$\mu$m. The typical column densities of the cores are $ N(H_2)\sim 3.8…

Astrophysics · Physics 2009-10-31 N. E. Jessop , D. Ward-Thompson

Dynamical expansion of H II regions around star clusters plays a key role in dispersing the surrounding dense gas and therefore in limiting the efficiency of star formation in molecular clouds. We use a semi-analytic method and numerical…

Astrophysics of Galaxies · Physics 2016-03-23 Jeong-Gyu Kim , Woong-Tae Kim , Eve C. Ostriker