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Related papers: A Search for Small-Scale Clumpiness in Dense Cores…

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We investigate how the properties of Galactic giant molecular clouds (GMCs) and their denser substructures (clumps) correlate with the local star formation rate. We trace clouds using the $^{12}$CO(3-2) transition, as observed by the CO…

Astrophysics of Galaxies · Physics 2019-09-04 Erika Zetterlund , Jason Glenn , Erik Rosolowsky

High-angular resolution observations of dense molecular cores show that these cores can be clumpier at smaller scales, and that some of these clumps can also be unbound or transient. The use of chemical models of the evolution of the…

Astrophysics of Galaxies · Physics 2015-06-05 Oscar Morata , Josep Miquel Girart , Robert Estalella , Robin T. Garrod

Massive stars play an important role in the Universe. Unlike low-mass stars, the formation of these objects located at great distances is still unclear. It is expected to be governed by some combination of self-gravity, turbulence, and…

Astrophysics of Galaxies · Physics 2024-08-07 A. G. Pazukhin , I. I. Zinchenko , E. A. Trofimova

We have mapped over 50 massive, dense clumps with four dense gas tracers: HCN J=1-0 and 3-2; and CS J=2-1 and 7-6 transitions. Spectral lines of optically thin H^{13}CN 3-2 and C^{34}S 5-4 were also obtained towards the map centers. These…

Astrophysics of Galaxies · Physics 2015-05-18 Jingwen Wu , Neal Evans , Yancy Shirley , Claudia Knez

(Abridged) We present a series of decaying turbulence simulations that represent a cluster-forming clump within a molecular cloud, investigating the role of magnetic fields on the formation of potential star-forming cores. We present an…

Astrophysics · Physics 2007-11-07 David A. Tilley , Ralph E. Pudritz

Observations reveal concentrations of molecular line emission on the sky, called ``clumps,'' in dense, star-forming molecular clouds. These clumps are believed to be the eventual sites of star formation. We study the three-dimensional…

Astrophysics · Physics 2009-11-07 C. F. Gammie , Y. -T. Lin , J. M. Stone , E. C. Ostriker

High-latitude ($|b|>30^{\circ}$) molecular clouds have virial parameters that exceed 1, but whether these clouds can form stars has not been studied systematically. Using JCMT SCUBA-2 archival data, we surveyed 70 fields that target…

The dense cloud associated with W40, one of the nearby H II regions, has been studied in millimeter-wave molecular lines and in 1.2 mm continuum. Besides, 1280 MHz and 610 MHz interferometric observations have been done. The cloud has…

Astrophysics of Galaxies · Physics 2015-06-17 L. Pirogov , D. K. Ojha , M. Thomasson , Y. -F. Wu , I. Zinchenko

Observations of distinct positions in Orion and W3 revealed ripples on the HCN(1-0), HCO^+(1-0) and CO(1-0) line profiles which can be result of emission of large number of unresolved thermal clumps in the beam that move with random…

Astrophysics of Galaxies · Physics 2009-03-26 L. E. Pirogov , I. I. Zinchenko , L. E. B. Johansson , J. Yang

Massive stars play an important role in the Universe. Unlike low-mass stars, the formation of these objects located at great distances is still unclear. It is expected to be governed by some combination of self-gravity, turbulence, and…

Astrophysics of Galaxies · Physics 2024-12-30 A. G. Pazukhin , I. I. Zinchenko , E. A. Trofimova

In order to search for intensity fluctuations on the HCN(1--0) and HCO$^+$(1--0) line profiles which could arise due to possible small-scale inhomogeneous structure long-time observations of the S140 and S199 high-mass star-forming cores…

Astrophysics of Galaxies · Physics 2018-08-15 Lev Pirogov

We present the statistical properties of molecular clumps in the Galactic center 50 km s$^{-1}$ molecular cloud (GCM-0.02-0.07) based on observations of the CS $J=1-0$ emission line with the Nobeyama Millimeter Array. In the cloud, 37…

Astrophysics of Galaxies · Physics 2015-06-04 Masato Tsuboi , Atsushi Miyazaki

We present a preliminary analysis of the small-scale structure found in new 70-520 micron continuum maps of the Rosette molecular cloud (RMC), obtained with the SPIRE and PACS instruments of the Herschel Space Observatory. We find 473…

We report the second complete molecular line data release from the {\em Census of High- and Medium-mass Protostars} (CHaMP), a large-scale, unbiased, uniform mapping survey at sub-parsec resolution, of mm-wave line emission from 303…

Astrophysics of Galaxies · Physics 2017-03-15 Peter J. Barnes , Audra K. Hernandez , Stefan N. O'Dougherty , William J. Schap , Erik Muller

We present molecular line and dust continuum observations of a Planck-detected cold cloud, G074.11+00.11. The cloud consists of a system of curved filaments and a central star-forming clump. The clump is associated with several infrared…

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

We report results of the observations of 15 regions in several molecular lines for a statistical study of massive cluster-forming clumps. We identified 24 clumps based on the C18O (J=1-0) data obtained by the NRO 45 m telescope, and found…

Astrophysics of Galaxies · Physics 2018-03-21 Tomomi Shimoikura , Kazuhito Dobashi , Fumitaka Nakamura , Tomoaki Matsumoto , Tomoya Hirota

We carry out a systematic study of the density structure of gas in the Central Molecular Zone (CMZ) in the Galactic center by extracting clumps from the APEX Telescope Large Area Survey of the Galaxy survey at 870 $\mu$m. We find that the…

Astrophysics of Galaxies · Physics 2020-07-15 Guang-Xing Li , Chuan-Peng Zhang

Some well-studied Herbig Haro objects have associated with them one or more cold, dense, and quiescent clumps of gas. We propose that such clumps near an HH object can be used as a general measure of clumpiness in the molecular cloud that…

Astrophysics of Galaxies · Physics 2015-05-14 W. Whyatt , J. M. Girart , S. Viti , R. Estalella , D. A. Williams

The properties of molecular clouds associated with 10 HII regions were studied using CO observations. We identified 142 dense clumps within our sample and found that our sources are divided into two categories: those with clumps that show a…

Solar and Stellar Astrophysics · Physics 2015-05-27 Mohaddesseh Azimlu , Michel Fich
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