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Turbulence has the potential for creating gas density enhancements that initiate cloud and star formation (SF), and it can be generated locally by SF. To study the connection between turbulence and SF, we looked for relationships between SF…

Astrophysics of Galaxies · Physics 2021-03-24 Deidre A. Hunter , Bruce G. Elmegreen , Haylee Archer , Caroline E. Simpson , Phil Cigan

Context: Supersonic nonthermal motions in molecular clouds are often interpreted as long-lived magnetohydrodynamic (MHD) waves. The propagation and amplitude of these waves is affected by local physical characteristics, most importantly the…

Astrophysics of Galaxies · Physics 2015-06-05 C. Pinto , A. Verdini , D. Galli , M. Velli

We present the first empirical constraints on the turbulent velocity field of the diffuse circumgalactic medium around four luminous QSOs at $z\!\approx\!0.5$--1.1. Spatially extended nebulae of $\approx\!50$--100 physical kpc in diameter…

We present a multiwavelength study of the filamentary infrared dark cloud (IRDC) G333.73+0.37. The region contains two distinct mid-infrared sources S1 and S2 connected by dark lanes of gas and dust. Cold dust emission from the IRDC is…

Astrophysics of Galaxies · Physics 2018-01-24 V. S. Veena , S. Vig , B. Mookerjea , A. Sanchez-Monge , A. Tej , C. H. Ishwara-Chandra

We have investigated the properties of the stellar mass function in the globular cluster NGC6397 using a large set of HST observations that include WFPC2 images in V and I, obtained at ~4' and 10' radial distances, and a series of deep…

Astrophysics · Physics 2009-10-31 Guido De Marchi , Francesco Paresce , Luigi Pulone

The dynamic activity in massive star forming regions prior to the formation of bright protostars is still not fully investigated. In this work we present observations of HCO+ J=1-0 and N2H+ J=1-0 made with the IRAM 30m telescope towards a…

Astrophysics of Galaxies · Physics 2017-12-13 A. Traficante , G. A. Fuller , R. J. Smith , N. Billot , A. Duarte-Cabral , N. Peretto , S. Molinari , J. E. Pineda

We present the results of an investigation of the effects of Far Ultraviolet (FUV) radiation from hot early type OB stars on clumps in star-forming molecular clouds. Clumps in Photodissociation regions (PDRs) undergo external heating which,…

Astrophysics · Physics 2009-11-07 Uma Gorti , David Hollenbach

Aims: We study the fragmentation and dynamical properties of a massive starless gas clump at the onset of high-mass star formation. Methods: Based on Herschel continuum data we identify a massive gas clump that remains far-infrared dark up…

Astrophysics of Galaxies · Physics 2015-06-15 H. Beuther , H. Linz , J. Tackenberg , Th. Henning , O. Krause , S. Ragan , M. Nielbock , R. Launhardt , S. Bihr , A. Schmiedeke , R. Smith , T. Sakai

Infrared-dark clouds (IRDCs) are believed to be the birthplaces of rich clusters and thus contain the earliest phases of high-mass star formation. We use the Green Bank Telescope (GBT) and Very Large Array (VLA) maps of ammonia (NH3) in six…

Astrophysics of Galaxies · Physics 2015-06-03 Sarah E. Ragan , Fabian Heitsch , Edwin A. Bergin , David Wilner

In recent years, it has been demonstrated that massive stars see their infant circumstellar medium shaped into a large, irradiated, gravitationally unstable accretion disc during their early formation phase. Such discs constitute the gas…

Solar and Stellar Astrophysics · Physics 2024-05-31 D. M. -A. Meyer , E. Vorobyov

Metal-rich globular clusters trace the formation of bulges. Abundance ratios in the metal-rich globular clusters such as NGC 6553 can constrain the formation timescale of the Galactic bulge. The purpose of this study is determine the…

The abundance of brown dwarfs (BDs) in young clusters is a diagnostic of star formation theory. Here we revisit the issue of determining the substellar initial mass function (IMF), based on a comparison between NGC1333 and IC348, two…

Solar and Stellar Astrophysics · Physics 2015-06-17 Aleks Scholz , Vincent Geers , Paul Clark , Ray Jayawardhana , Koraljka Muzic

Planet-disc interactions build up local pressure maxima that may halt the radial drift of protoplanetary dust, and pile it up in rings and crescents. ALMA observations of the HD135344B disc revealed two rings in the thermal continuum…

The spatial range for feedback from star formation varies from molecular cloud disruption on parsec scales to supershells and disk blowout on kiloparsec scales. The relative amounts of energy and momentum given to these scales is important…

Astrophysics of Galaxies · Physics 2022-04-13 Bruce G. Elmegreen , Zorayda Martinez , Deidre A. Hunter

For understanding the nature of gaseous flows in star-forming regions of nearby galaxies it is usually utilized the relation between surface brightness in H$\alpha$ line and velocity dispersion of ionized gas known as ''surface brightness…

Astrophysics of Galaxies · Physics 2024-04-02 Evgemii O. Vasiliev , Yuri A. Shchekinov

We present for the first time a two-dimensional velocity field of the central region of the grand-design spiral galaxy NGC 5248, at 0.9 arcsec spatial resolution. The H-alpha velocity field is dominated by circular rotation. While no…

Astrophysics · Physics 2008-11-26 S. Laine , J. H. Knapen , D. Perez-Ramirez , P. Englmaier , M. Matthias

High-resolution, 2-D hydrodynamical simulations with a large dynamic range are performed to study the turbulent nature of the interstellar medium (ISM) in galactic disks. The simulations are global, where the self-gravity of the ISM,…

Astrophysics · Physics 2008-11-26 Keiichi Wada , Gerhardt Meurer , Colin A. Norman

We report the detection of new ammonia masers in the non-metastable (8,6) and (11,9) transitions towards the massive star forming region NGC6334I. Observations were made with the ATCA interferometer and the emitting region appears…

Astrophysics · Physics 2009-11-13 A. J. Walsh , S. N. Longmore , S. Thorwirth , J. S. Urquhart , C. R. Purcell

VV124 (UGC 4879) is an isolated, dwarf irregular/dwarf spheroidal (dIrr/dSph) transition-type galaxy at a distance of 1.36 Mpc. Previous low-resolution spectroscopy yielded inconsistent radial velocities for different components of the…

Astrophysics of Galaxies · Physics 2013-03-13 Evan N. Kirby , Judith G. Cohen , Michele Bellazzini

NGC 253 hosts the nearest nuclear starburst. Previous observations show a region rich in molecular gas, with dense clouds associated with recent star formation. We used ALMA to image the 350 GHz dust continuum and molecular line emission…