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We present results of an extensive mapping survey of N2H+(1-0) in about 60 low mass cloud cores already mapped in the NH3(1,1) inversion transition line. The survey has been carried out at the FCRAO antenna with an angular resolution about…

Astrophysics · Physics 2010-04-06 Paola Caselli , Priscilla J. Benson , Philip C. Myers , Mario Tafalla

The ALMA-IMF Large Program provides multi-tracer observations of 15 Galactic massive protoclusters at matched sensitivity and spatial resolution. We focus on the dense gas kinematics of the G353.41 protocluster traced by N$_2$H$^+$ (1$-$0),…

We performed sub-parsec ($\sim$ 0.014 pc) scale simulations of cloud-cloud collisions of two idealized turbulent molecular clouds (MCs) with different masses in the range of $0.76 - 2.67 \times 10^4$M$_{\odot}$ and with collision speeds of…

Astrophysics of Galaxies · Physics 2018-02-15 Ken Takahira , Kazuhiro Shima , Elizabeth J. Tasker , Asao Habe

Theoretically, misalignment between the magnetic field and rotational axis in a dense core is considered to be dynamically important in the star formation process, however, extent of this influence remains observationally unclear. For a…

Observations suggest that filaments in molecular clouds can grow by mass accretion while forming cores via fragmentation. Here we present one of the first large sample studies of filament accretion using velocity gradient measurements of…

We present the analysis of the velocity structure of the intracluster gas near the core of Abell 3526 obtained with two off-center Chandra observations, specifically designed to eliminate errors due to spatial variations of the instrumental…

Astrophysics · Physics 2009-11-13 Renato A. Dupke , Joel N. Bregman

We investigate star formation at very early evolutionary phases in five massive clouds in the inner 500 pc of the Galaxy, the Central Molecular Zone. Using interferometer observations of H$_2$O masers and ultra-compact H II regions, we find…

Spectrum analysis at 3 mm of the central region ($r\sim$800 pc) of NGC\,4303 showed molecular gas lines of both dense gas tracers (HCN, HNC, HCO$^+$, and C$_2$H) and diffuse gases ($^{13}$CO and C$^{18}$O). Molecular gas derived parameters:…

We use numerical simulations of molecular cloud formation in the colliding flow scenario to investigate the reliability of observational estimates of the angular momenta of early-state, low-mass protostellar cores. We show that, with…

Astrophysics of Galaxies · Physics 2018-08-22 Shangjia Zhang , Lee Hartmann , Manuel Zamora , Aleksandra Kuznetsova

We present an analysis comparing the properties of 45 giant molecular clouds (GMCs) in M33 and the atomic hydrogen (HI) with which they are associated. High-resolution VLA observations are used to measure the properties of HI in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 N. Imara , F. Bigiel , L. Blitz

We report Submillimeter Array molecular line observations in the 345 GHz band of five massive dense cores, Cyg-N38, Cyg-N43, Cyg-N48, Cyg-N51, and Cyg-N53 in the DR21 filament. The molecular line data reveal several dynamical features of…

Astrophysics of Galaxies · Physics 2018-10-10 Tao-Chung Ching , Shih-Ping Lai , Qizhou Zhang , Josep M. Girart , Keping Qiu , Hauyu B. Liu

A total of 64 ATOMS sources at different evolutionary stages were selected to investigate the kinematics and dynamics of gas structures under feedback. We identified dense gas structures based on the integrated intensity map of…

Astrophysics of Galaxies · Physics 2023-12-05 J. W. Zhou , S. Dib , F. Wyrowski , T. Liu , S. H. Li , P. Sanhueza , M. Juvela , F. W. Xu , H. L. Liu , T. Baug , Y. P. Peng , K. M. Menten , L. Bronfman , C. W. Lee

We performed sub-parsec (~0.06pc) scale simulations of two idealised molecular clouds with different masses undergoing a collision. Gas clumps with density greater than 1e-20 g/cm3 (0.3e4 cm-3) were identified as pre-stellar cores and…

Astrophysics of Galaxies · Physics 2015-06-22 Ken Takahira , Elizabeth J. Tasker , Asao Habe

We found that in regions of high mass star formation the CS emission correlates well with the dust continuum emission and is therefore a good tracer of the total mass while the N$_2$H$^+$ distribution is frequently very different. This is…

We present an Integral Field Unit survey of 73 galaxy clusters and groups with the VIsible Multi Object Spectrograph (VIMOS) on VLT. We exploit the data to determine the H$\alpha$ gas dynamics on kpc-scales to study the feedback processes…

Dense core collisions, previously regarded as minor in star formation, are proposed to play a significant role in structure formation around protostellar envelopes and binary formation. Using archival data of nearby star-forming regions, we…

Astrophysics of Galaxies · Physics 2024-02-20 Yuta Yano , Fumitaka Nakamura , Shinichi W. Kinoshita

Context. Low-mass star-forming cores differ from their surrounding molecular cloud in turbulence, shape, and density structure. Aims. We aim to understand how dense cores form out of the less dense cloud material by studying the connection…

Astrophysics of Galaxies · Physics 2015-05-28 A. Hacar , M. Tafalla

We have mapped the large-scale structure of the Serpens cloud core using moderately optically thick (13CO(1--0) and CS(2--1)) and optically thin tracers (C18O(1--0), C34S(2--1), and N2H+(1--0)), using the 16-element focal plane array…

Astrophysics · Physics 2009-11-07 L. Olmi , L. Testi

Observations of the Milky Way and nearby galaxies show that dense molecular gas correlates with recent star formation, suggesting that the formation of this gas phase may help regulate star formation. A key test of this idea requires…

Astrophysics of Galaxies · Physics 2015-06-18 Amanda A. Kepley , Adam K. Leroy , David Frayer , Antonio Usero , Josh Marvil , Fabian Walter