Related papers: Deconstructing the High-Mass Star-Forming Region I…
We have observed the central region of the IR-dark cloud filament associated with IRAS 18507+0121 at millimeter wavelengths in CO(1-0), 13CO(1-0), and C18O(1-0) line emission and with the Spitzer Space Telescope at mid-IR wavelengths. Five…
In the massive star-forming region IRAS 21078+5211, a highly fragmented cluster (0.1~pc in size) of molecular cores is observed, located at the density peak of an elongated (1~pc in size) molecular cloud. A small (1~km/s per 0.1~pc) LSR…
The formation process of high-mass stars (>8M$_\odot$) is poorly constrained, particularly, the effects of clump fragmentation creating multiple systems and the mechanism of mass accretion onto the cores. We study the fragmentation of dense…
We have carried out a new kinematical analysis of the molecular gas in the Sh2-233 region by using the CO $J$ = 2-1 data taken at $\sim$0.5 pc resolution. The molecular gas consists of a filamentary cloud of 5-pc length with 1.5-pc width…
We have observed the massive star forming region, IRAS 18507+0121, at millimeter wavelengths in 3 mm continuum emission and H13CO+(J=1-0) and SiO(v=0, J=2-1) line emission, and at near-infrared wavelengths between 1.2 and 2.1 microns. Two…
We present a multi-line study of the massive star-forming region IRAS 22506+5944. A new 6.7 GHz methanol maser was detected. 12CO, 13CO, C18O and HCO+ J = 1-0 transition observations reveal a star formation complex consisting mainly of two…
We present molecular line and submillimeter dust continuum observations of the Lynds 870 cloud in the vicinity of IRAS 20231+3440. Two submillimeter cores, SMM1 and SMM2, are identified mapping the 870 micron dust continuum and ammonia…
We aim at studying with high angular resolution a dense core associated with a low-luminosity IRAS source, IRAS 00213+6530, in order to investigate whether low mass star formation is really taking place in isolation. We performed…
We present observations of continuum and molecular lines towards the protostar candidates IRAS 21307+5049 and IRAS 22172+5549. Single-dish maps in the 12CO(2--1), C18O(2--1), HCO+(1--0) lines and sub-mm continuum are compared with…
We present a high-angular-resolution molecular line and millimeter continuum study of the massive star formation site IRAS 05358+3543. The most remarkable feature is a highly collimated (collimation factor ~10) and massive (>10 M_sun)…
We report the discovery of two very cold and massive molecular cloud cores in the region ISOSS J18364-0221. The object has been identified by a systematic search for very early evolutionary stages of high-mass stars using the 170 micron…
We report sensitive ATCA radio-continuum observations toward IRAS 15596-5301 and 16272-4837, two luminous objects (> 2x10^4 Lsun) thought to represent massive star-forming regions in early stages of evolution (due to previously undetected…
We present high angular resolution observations toward two massive star forming regions IRAS 18264-1152 and IRAS 23151+5912 with the Plateau de Bure Interferometer (PdBI) in the SiO (J=2-1) and H$^{13}$CO$^{+}$ (J=1-0) lines and at 1.3 mm…
The mapping observations of CO $J=2-1$, CO $J=3-2$, $^{13}$CO $J=2-1$ and $^{13}$CO $J=3-2$ lines in the direction of IRAS 22506+5944 have been made. The results show that the cores in the $J=2-1$ transition lines have a similar morphology…
The study of physical and chemical properties of massive protostars is critical to better understand the evolutionary sequence which leads to the formation of high-mass stars. IRAS 18151-1208 is a nearby massive region (d = 3kpc, L ~ 20000…
We present high-angular resolution sub-millimeter continuum images and molecular line spectra obtained with the SMA toward two massive cores that lie within Infrared Dark Clouds; one actively star-forming (G034.43+00.24 MM1) and the other…
The L1551 molecular cloud contains two small clusters of Class 0 and I protostars, as well as a halo of more evolved Class II and III YSOs, indicating a current and at least one past burst of star formation. We present here new, sensitive…
Massive stars (M $\gsim 10$ \msun) form from collapse of parsec-scale molecular clumps. How molecular clumps fragment to give rise to massive stars in a cluster with a distribution of masses is unclear. We search for cold cores that may…
The infrared dark clouds (IRDCs) G11.11$-$0.12 and G28.34$+$0.06 are two of the best-studied IRDCs in our Galaxy. These two clouds host clumps at different stages of evolution, including a massive dense clump in both clouds that is dark…
We present a multi-wavelength observational study of a low-mass star-forming region, L1251-C, with observational results at wavelengths from the near-infrared to the millimeter. Spitzer Space Telescope observations confirmed that IRAS…