Related papers: High Resolution CO Observations of Massive Star Fo…
Aims: We wish to establish whether sequential star formation is taking place at the periphery of the Galactic HII region Sh2-212. Methods: We present CO millimetre observations of this region obtained at the IRAM 30-m telescope to…
Aims: Previous observations of the young massive star formation region IRAS 19410+2336 have revealed strong outflow activity with several interacting outflows. We aim to get a better understanding of the outflow activity in this region by…
Aims: We aim to understand the star formation associated with the luminous young stellar object (YSO) IRAS 18345-0641 and to address the complications arising from unresolved multiplicity in interpreting the observations of massive…
Context. With the latest infrared surveys, the number of massive protostellar candidates has increased significantly. New studies have posed additional questions on important issues about the formation, evolution, and other phenomena…
Massive stars form deeply embedded in dense molecular gas, which they stir and heat up and ionize. During an early phase, the ionization is confined to hypercompact HII regions, and the stellar radiation is entirely absorbed by dust, giving…
The evolutionary sequence for high-mass star formation starts with massive starless clumps that go on to form protostellar, young stellar objects and then compact HII regions. While there are many examples of the three later stages, the…
We present an analysis of the QUARKS survey sample, focusing on protoclusters where Hot Molecular Cores (HMCs, traced by CH3CN(12--11)) and UC HII regions (traced by H30\alpha/H40\alpha) coexist. Using the high-resolution, high-sensitivity…
Although fundamental for astrophysics, the processes that produce massive stars are not well understood. Large distances, high extinction, and short timescales of critical evolutionary phases make observations of these processes…
We present a comprehensive physical and chemical study of the fragmentation and star formation activity towards the massive clump AGAL G338.9188+0.5494 harbouring the extended green object EGO 338.92+0.55(b). The presence of an EGO embedded…
We present a detailed 1.2 mm continuum and CS spectral line study of a large sample of 69 massive star forming regions in very early stages of evolution, most of them prior to building up an ultracompact HII region. The continuum data show…
We present Chandra/ACIS images of several high-mass star-forming regions. The massive stellar clusters powering these HII regions are resolved at the arcsecond level into hundreds of stellar sources, similar to those seen in closer young…
We perform a joint-analysis of high spatial resolution molecular gas and star-formation rate (SFR) maps in main-sequence star-forming galaxies experiencing galactic-scale outflows of ionised gas. Our aim is to understand the mechanism that…
Young massive stars or clusters are often observed at the peripheries of HII regions. What triggers star formation at such locations? Among the scenarios that have been proposed, the `collect and collapse' process is particularly attractive…
Little is known about how high-mass stars form. Around 30\% of the young high-mass stars in the Galaxy are observed at the edges of ionized (HII) regions. Therefore these are places of choice to study the earliest stages of high-mass star…
We present a study of molecular outflows using six molecular lines (including 12CO/13CO/C18O/HCO+(J = 1-0) and SiO/CS(J = 2-1)) toward nine nearby high-mass star-forming regions with accurate known distances. This work is based on the…
Observations have suggested that galactic outflows contain substantial amounts of dense and clumpy molecular gas, creating favourable conditions for igniting star formation. Indeed, theoretical models and hydrodynamical simulations have…
The [CII] fine--structure line at 158um is an excellent tracer of the warm diffuse gas in the ISM and the interfaces between molecular clouds and their surrounding atomic and ionized envelopes. Here we present the initial results from…
This work aims at investigating the molecular gas component in the vicinity of two young stellar object (YSO) candidates identified at the border of the HII region G034.8-0.7 that is evolving within a molecular cloud shocked by the SNR W44.…
During star cluster formation, ongoing mass accretion is resisted by stellar feedback in the form of protostellar outflows from the low-mass stars and photo-ionization and radiation pressure feedback from the massive stars. We model the…
We present evidence of large-scale outflows from three low-mass (log(M/M_sun)~9.75) star-forming (SFR >4 M_sun/yr) galaxies observed at z=1.24, z=1.35 and z=1.75 in the 3D-HST Survey. Each of these galaxies is located within a projected…