https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 Characterizing the properties of cluster precursors in the MALT90 survey https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31211 Wed 11 Apr 2018 17:23:17 AEST ]]> The Radio Ammonia Mid-plane Survey (RAMPS) pilot survey https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34949 1,6–52,3 maser line at 22.235 GHz, and several other molecular lines. We present a representative portion of the data from the pilot survey, including NH₃(1,1) and NH₃(2,2) integrated intensity maps, H₂O maser positions, maps of NH₃ velocity, NH₃ line width, total NH₃ column density, and NH₃ rotational temperature. These data and the data cubes from which they were produced are publicly available on the RAMPS website (http://sites.bu.edu/ramps/).]]> Tue 03 Sep 2019 18:17:26 AEST ]]> Infall signatures in a prestellar core embedded in the high-mass 70 μm Dark IRDC G331.372-00.116 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34952 ⊙), cold (14 K) 3.6–70 μm dark IRDC, G331.372-00.116. This infrared dark cloud (IRDC) has the potential to form high-mass stars, and given the absence of current star formation signatures, it seems to represent the earliest stages of high-mass star formation. We have mapped the whole IRDC with the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.1 and 1.3 mm in dust continuum and line emission. The dust continuum reveals 22 cores distributed across the IRDC. In this work, we analyze the physical properties of the most massive core, ALMA1, which has no molecular outflows detected in the CO (2–1), SiO (5–4), and H₂CO (3–2) lines. This core is relatively massive (M = 17.6 M ), subvirialized (virial parameter α vir = Mvir/M = 0.14), and is barely affected by turbulence (transonic Mach number of 1.2). Using the HCO+ (3–2) line, we find the first detection of infall signatures in a relatively massive, prestellar core (ALMA1) with the potential to form a high-mass star. We estimate an infall speed of 1.54 km s−1 and a high accretion rate of 1.96 × 10−3 M yr−1. ALMA1 is rapidly collapsing, out of virial equilibrium, which is more consistent with competitive accretion scenarios rather than the turbulent core accretion model. On the other hand, ALMA1 has a mass ~6 times larger than the clumps Jeans mass, as it is in an intermediate mass regime (MJ = 2.7 ⊙), contrary to what both the competitive accretion and turbulent core accretion theories predict.]]> Tue 03 Sep 2019 17:56:50 AEST ]]>