Related papers: Very Large Array Observations of Ammonia in Infrar…
Infrared dark clouds are massive, dense clouds seen in extinction against the IR Galactic background. Many of these objects appear to be on the verge of star and star cluster formation. Our aim is to understand the physical properties of…
We present the results of ammonia observations towards 66 massive star forming regions identified by the Red MSX source survey. We have used the Green Bank Telescope and the K-band focal plane array to map the ammonia NH3 (1,1) and (2,2)…
[abridged] We present interferometric maps of ammonia (NH3) of the nearby starburst galaxy NGC 253 [star formation rate: ~2.8 Mo yr^(-1)]. The observations have been taken with the Australia Telescope Compact Array and include the para-NH3…
Stars are born from dense cores in molecular clouds. Observationally, it is crucial to capture the formation of cores in order to understand the necessary conditions and rate of the star formation process. The {\it Atacama Large Mm/sub-mm…
The physical, chemical and kinetic characteristics of 12 northern infrared dark clouds (IRDCs) are systematic studied using the $\rm ^{13}CO $ (1-0) and $\rm C^{18}O$ (1-0) lines, observed with the PMO 13.7 m radio telescope, the 1.1 mm…
The dense, cold regions where high-mass stars form are poorly characterised, yet they represent an ideal opportunity to learn more about the initial conditions of high-mass star formation (HMSF), since high-mass starless cores (HMSCs) lack…
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…
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…
Infrared Dark Clouds are expected to harbor sources in different, very young evolutionary stages. To better characterize these differences, we observed a sample of 43 massive Infrared Dark Clouds, originally selected as candidate high-mass…
Dense cores in massive, parsec-scale molecular clumps are sites that harbor protocluster formation. We present results from observations towards a hub-filament structure of a massive Infrared Dark Cloud (IRDC) G14.225-0.506 using the…
To study the fragmentation and gravitational collapse of dense cores in infrared dark clouds (IRDCs), we have obtained submillimeter continuum and spectral line data as well as multiple inversion transitions of NH3 and H2O maser data of…
Infrared-dark clouds (IRDCs) harbor the early phases of cluster and high-mass star formation and are comprised of cold (~20 K), dense (n > 10$^4$ cm$^{-3}$) gas. The spectral energy distribution (SED) of IRDCs is dominated by the…
Infrared Dark Clouds (IRDCs) are dark clouds seen in silhouette in mid-infrared surveys. They are thought to be the birthplace of massive stars, yet remarkably little information exists on the properties of the population as a whole (e.g.…
We present a multiwavelength study of the filamentary infrared dark cloud (IRDC) G333.73+0.37. The region contains two distinct mid-infrared sources S1 and S2 connected by dark lanes of gas and dust. Cold dust emission from the IRDC is…
We present NH3(1,1) and NH3(2,2) observations of MBM 12, the closest known molecular cloud (65 pc distance), aimed to find evidence for on-going star formation processes. No local temperature (with a T_rot upper limit of 12 K) nor linewidth…
We observed 42 molecular condensations within previously identified bright-rimmed clouds in the ammonia rotational inversion lines NH3 (1,1), (2,2), (3,3) and (4,4) using the Green Bank Telescope in Green Bank, West Virginia. Using the…
The initial conditions found in infrared dark clouds (IRDCs) provide insights on how high-mass stars and stellar clusters form. We have conducted high-angular resolution and high-sensitivity observations toward thirty-nine massive IRDC…
To characterize the initial conditions for intermediate- to high-mass star formation, we observed two Infrared Dark Clouds (IRDCs) that remain absorption features up to 70mum wavelength, with the PdBI in the 3.23mm dust continuum as well as…
The initial conditions of massive star and star cluster formation are expected to be cold, dense and high column density regions of the interstellar medium, which can reveal themselves via near, mid and even far-infrared absorption as…
We present new NH3 (1,1), (2,2), and (4,4) observations from the Karl G. Jansky Very Large Array (VLA) compiled with work in the literature to explore the range of conditions observed in young, massive star-forming regions. To sample the…