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Using new continuum and molecular line data from the ALMA Three-millimeter Observations of Massive Star-forming Regions (ATOMS) survey and archival VLA, 4.86 GHz data, we present direct observational evidence of hierarchical triggering…
Studies of the structure and kinematics of cores associated with the regions of massive star and star cluster formation are necessary for constructing scenario for the evolution of these objects. We analyzed spectral maps of the massive…
[Context] Two competing models describe the formation of massive stars in objects like the Orion Trapezium. In the turbulent core accretion model, the resulting stellar masses are directly related to the mass distribution of the cloud…
The study of hyper-compact (HC) or ultra-compact (UC) HII regions is fundamental to understanding the process of massive (> 8 M_sun) star formation. We employed Atacama Large Millimeter/submillimeter Array (ALMA) 1.4 mm Cycle 6 observations…
The role of accretion disks in the formation of low-mass stars has been well assessed by means of high angular resolution observations at various wavelengths. These findings confirm the prediction that conservation of angular momentum…
(Abridged) A new type of self-similar hot viscous radiative accretion flow onto a rapidly spinning neutron star has recently been discovered. This ``hot brake'' flow forms in the two-temperature zone (close to a central object), but at a…
We carried out line survey observations at the 26-30 GHz band toward the four high-mass star-forming regions containing hot cores, G10.30-0.15, G12.89+0.49, G16.86-2.16, and G28.28-0.36, with the Robert C. Byrd Green Bank Telescope. We have…
Sufficiently massive clumps of molecular gas collapse under self-gravity and fragment to spawn a cluster of stars that have a range of masses. We investigate observationally the early stages of formation of a stellar cluster in a massive…
We present observational data for two main components (S255IR and S255N) of the S255 high mass star forming region in continuum and molecular lines obtained at 1.3 mm and 1.1 mm with the SMA, at 1.3 cm with the VLA and at 23 and 50 cm with…
We present the results of fully 3-D hydrodynamic simulations of the gravitational collapse of isolated, turbulent molecular cloud cores. Starting from initial states of hydrostatic equilibrium, we follow the collapse of both singular and…
We present observations of the intermediate to massive star-forming region I05345+3157 using the molecular line tracer CS(2-1) with CARMA to reveal the properties of the dense gas cores. Seven gas cores are identified in the integrated…
We aim to reveal the chemistry of carbon-chain molecules in high-mass star-forming regions from molecular level to chemical evolution, applying the methods established in low-mass star-forming regions. In this proceeding, we summarize the…
This study is part of the project ``CORE'', an IRAM/NOEMA large program consisting of observations of the millimeter continuum and molecular line emission towards 20 selected high-mass star forming regions. We focus on IRAS23385+6053, which…
Using the Owens Valley and Nobeyama Radio Observatory interferometers, we carried out an unbiased search for hot molecular cores and ultracompact UC HII regions toward the high-mass star forming region G19.61--0.23. In addition, we…
This paper is the third in a series of ammonia multilevel imaging studies in well-known high-mass star forming regions. Using the JVLA, we have mapped the hot and dense molecular gas in W51 Main, with about 0.2 arcsec angular resolution, in…
Characterizing rotation, infall and accretion disks around high-mass protostars is an important topic in massive star formation research. With the Australia Telescope Compact Array and the Very Large Array we studied a massive disk…
We present single-dish (sub)millimeter observations of gas and dust in the Galactic high-mass star-forming region G19.61-0.23, with the aim of studying the large-scale properties and physical conditions of the molecular gas across the…
We have used the IRAM 30-m and FCRAO 14-m telescopes to observe the molecular clumps associated with 12 ultracompact (UC) HII regions in the J=6-5, 8-7 and 13-12 rotational transitions of methyl-acetylene (CH3C2H). Under the assumption of…
We present molecular line mapping of the Giant Molecular Cloud G1.6-0.025, which is located at the high longitude end of the Central Molecular Zone of our Galaxy. We assess the degree of star formation activity in that region using several…
(abridged) We present the results of an extensive infrared study of the massive star-forming region G9.62+0.19. The data cover information from broad- and narrow-band filters in the wavelength range from 1 to 19 micrometer and are obtained…