Related papers: Massive and low-mass protostars in massive "starle…
Context: The earliest stages of high-mass star formation are still poorly characterized. It is also unknown whether the initial conditions vary with environment. Aims: We want to investigate the youngest massive gas clumps in the…
In this contribution, our knowledge of the initial conditions under which massive star formation takes place is reviewed. Massive stars are born in massive clumps of giant molecular clouds (GMCs), hence first the properties of GMCs are…
The last decade has witnessed significant advances in our observational understanding of the earliest stages of low-mass star formation. The advent of sensitive receivers on large radio telescopes such as the JCMT and IRAM 30m MRT has led…
We present new 3-mm continuum and molecular lines observations from the ATOMS survey towards the massive protostellar clump, MM1, located in the filamentary infrared dark cloud (IRDC), G034.43+00.24 (G34). The lines observed are the tracers…
Infrared Dark Clouds (IRDCs) represent the earliest observed stages of clustered star formation, characterized by large column densities of cold and dense molecular material observed in silhouette against a bright background of mid-IR…
The onset of massive star formation is not well understood because of observational and theoretical difficulties. To find the dense and cold clumps where massive star formation can take place, we compiled a sample of high infrared…
We present high resolution (0.2", 1000 AU) 1.3 mm ALMA observations of massive infrared dark cloud clump, G028.37+00.07-C1, thought to harbor the early stages of massive star formation. Using $\rm N_2D^+$(3-2) we resolve the previously…
We have performed a dense core survey toward the Infrared Dark Cloud G14.225-0.506 at 3 mm continuum emission with the Atacama Large Millimeter/Submillimeter Array (ALMA). This survey covers the two hub-filament systems with an angular…
Ever since their discovery, Infrared dark clouds (IRDCs) are generally considered to be the sites just at the onset of high-mass (HM) star formation. In recent years, it has been realized that not all IRDCs harbour HM Young Stellar Objects…
Cold dark clouds are nearby members of the densest and coldest phase in the galactic interstellar medium, and represent the most accessible sites where stars like our Sun are currently being born. In this review we discuss recent progress…
Context: Core accretion models of massive star formation require the existence of massive, starless cores within molecular clouds. Yet, only a small number of candidates for such truly massive, monolithic cores are currently known. Aims:…
We obtained 350 and 850 micron continuum maps of the infrared dark cloud G049.40-00.01. Twenty-one dense clumps were identified within G049.40-00.01 based on the 350 micron continuum map with an angular resolution of about 9.6". We present…
We present Submillimeter Array (SMA) $\lambda =$ 0.88 and 1.3 mm broad band observations, and the Jansky Very Large Array (VLA) observations in $\rm{NH_3}$ $(J,K) = (1,1)$ up to $(5,5)$, $\rm{H_2O}$ and $\rm{CH_3OH}$ maser lines toward the…
The IRDC SDC335.579-0.292 (SDC335) is a massive star-forming cloud found to be globally collapsing towards one of the most massive star forming cores in the Galaxy. SDC335 hosts three high-mass protostellar objects at early stages of their…
It is known that massive stars form as result of the fragmentation of molecular clumps. However, what is not clear is whether this fragmentation gives rise to cores massive enough to form directly high-mass stars, or leads to cores of low…
Infrared dark clouds (IRDCs) are potential hosts of the elusive early phases of high-mass star formation (HMSF). Here we conduct an in-depth analysis of the fragmentation properties of a sample of 10 IRDCs, which have been highlighted as…
I review massive star formation in our Galaxy, focusing on initial conditions in Infrared Dark Clouds (IRDCs), including the search for massive pre-stellar cores (PSCs), and modeling of later stages of massive protostars, i.e., hot…
The earliest phases of massive star formation are found in cold and dense infrared dark clouds (IRDCs). Since the detection method of IRDCs is very sensitive to the local properties of the background emission, we present here an alternative…
We report interferometric observations of the high-mass star-forming object IRAS 23033+5951. Our observations reveal two massive molecular cloud cores, designated IRAS 23033+5951-MMS1 and IRAS 23033+5951-MMS2. MMS1 has already formed a…
We present 1.3mm continuum and spectral line images of two massive molecular clumps P1 and P2 in the G28.34+0.06 region with the Submillimeter Array. While the two clumps contain masses of 1000 and 880 \msun, respectively, P1 has a…