Related papers: Two massive star-forming regions at early evolutio…
We present a multiwavelength study of the H II region Sh 2-301 (S301) using deep optical data, near-infrared data, radio continuum data and other archival data at longer wavelengths. A cluster of young stellar objects (YSOs) is identified…
We present results from JHKs imaging of the densest region of the W49 molecular cloud. In a recent paper (Alves & Homeier 2003), we reported the detection of (previously unknown) massive stellar clusters in the well-known giant radio HII…
In this paper we present the results of a mid infrared study of G49.5-0.4, or W51A, part of the massive starbirth complex W51. Combining public data from the $Spitzer$ IRAC camera, and Gemini mid infrared camera T-ReCS at 7.73, 9.69, 12.33…
Direct observations of accretion disks around high-mass young stellar objects would help to discriminate between different models of formation of massive stars. However, given the complexity of massive star forming regions, such studies are…
We present a submm study of the massive hot core G327.3-0.6 that constrains its physical parameters and environment. The APEX telescope was used to image CO and N2H+ emission, to observe lines from other molecules toward a hot and a cold…
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 present radio continuum observations of the high-mass young stellar object (HMYSO) G345.4938+01.4677 made using the Australia Telescope Compact Array (ATCA) at 5, 9, 17, and 19 GHz. These observations provide definite evidence that the…
We report the detection of three compact ($< 0.001$ pc) radio sources (CRSs) at K$_{a}$-band (0.9 cm) in the \uchiirs G040.54+2.59 (two CRSs) and G034.13+0.47 (one CRS). These CRSs have weak flux densities and are located at the center of…
We present ALMA sub-arcsecond-resolution observations of both continuum and molecular lines at 345 GHz towards the massive star-forming region IRAS 16351-4722 (hereafter I16351). A total of 12 dust cores were detected based on high spatial…
S255N is a luminous far-infrared source that contains many indications of active star formation but lacks a prominent near-infrared stellar cluster. We present mid-infrared through radio observations aimed at exploring the evolutionary…
We present high spatial resolution Submillimeter Array observations and supplementary single-dish photometry of the molecular gas and dust around IRAS 04158+2805, a young source with spectral type M5-M6 in the Taurus star-forming region. A…
The young massive star-forming region IRAS05358+3543 was observed at high-spatial resolution in the continuum emission at 3.1 and 1.2mm with the Plateau de Bure Interferometer, and at 875 and 438mum with the Submillimeter Array. We resolve…
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…
Aims: We have carried out an infrared study of the southern Galactic massive star forming region associated with IRAS 14416-5937. Methods: This star forming region has been mapped simultaneously in two far infrared bands at ~ 150 & 210…
The carriers of the 21 and 30\,$\mu$m emission features in infrared spectra of circumstellar envelopes are a long-standing enigma. In this paper, we present the results of molecular line observations toward two circumstellar envelopes…
A multiwavelength study of the star forming regions associated with IRAS 19111+1048 and IRAS 19110+1045 has been carried out. These have been simultaneously mapped in two far infrared bands at lambda_eff ~ 130 and 200 micron with ~1'…
The earliest stages of star formation are highlighted by complex interactions between accretion, outflow, and radiative processes, which shape the chemical and physical environment of the emerging protostar. James Webb Space Telescope…
It has been proposed that some hot molecular cores (HMCs) harbor a young embedded massive star, which heats an infalling envelope and accretes mass at a rate high enough to ``choke off'' an incipient HII region. This class of HMCs would…
We present multiwavelength investigation of morphology, physical-environment, stellar contents and star formation activity in the vicinity of star-forming region Sh 2-100. It is found that the Sh 2-100 region contains seven HII regions of…
If massive stars form by disk accretion, then bipolar outflows should be generated as in the case of low-mass star formation. High accretion rates lead to high outflow rates and make the wind density very large near the protostar. We…