Related papers: W49A: A starburst triggered by expanding shells
The W49A star-forming region is embedded in a 10^6 solar mass molecular cloud, one of the most massive in our Galaxy. It has been long known as one of the most luminous radio HII regions, containing 30-40 compact and ultracompact HII…
The star formation rates in starburst galaxies are orders of magnitude higher than in local star-forming regions, and the origin of this difference is not well understood. We use sub-mm spectral line maps to characterize the physical…
W51A is one of the most active star-forming region in our Galaxy, which contains giant molecular clouds with a total mass of 10^6 Msun. The molecular clouds have multiple velocity components over ~20 km/s, and interactions between these…
We present subarcsecond J, H, and Ks images (FWHM ~ 0.5") of an unbiased 5'x 5' (16pc x 16pc) survey of the densest region of the W49 giant molecular cloud. The observations reveal 4 massive stellar clusters (with stars as massive as \~120…
W49A is one of the most luminous giant H II (GH II) regions in our Galaxy. This star forming complex contains numerous compact and ultra-compact (UC) H II regions, extending over an area of 15 pc. It emits about 10^{51} Lyman continuum…
The Multi-Scale Continuum and Line Exploration of W49 (MUSCLE W49) is a comprehensive gas and dust survey of the giant molecular cloud (GMC) of W49A, the most luminous star-formation region in the Milky Way. It covers the entire GMC at…
One of the most prominent features of galaxy clusters is the presence of a dominant population of massive ellipticals in their cores. Stellar archaeology suggests that these gigantic beasts assembled most of their stars in the early…
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…
The massive and luminous star-forming region W49A is a well known Galactic candidate to probe the physical conditions and chemistry similar to those expected in external starburst galaxies. We aim to probe the physical and chemical…
We unveil the stellar wind driven shell of the luminous massive star-forming region of RCW 49 using SOFIA FEEDBACK observations of the [CII] 158 $\mu$m line. The complementary dataset of the $^{12}$CO and $^{13}$CO J = 3 - 2 transitions is…
We present high resolution observations of CS(J=1-0), H13CO+ (J=1-0), and SiO(v=0:J=1-0) lines, together with the 49GHz and 86GHz continuum emissions, toward W49N carried out with Nobeyama Millimeter Array. We identified 11 CS, 8 H13CO+,…
The HCN, HCO+, and HNC molecules are commonly used as tracers of dense star-forming gas in external galaxies, but such observations are spatially unresolved. Reliably inferring the properties of galactic nuclei and disks requires detailed…
The central 2x1 kpc of the starburst galaxy NGC 253 has been imaged using the Submillimeter Array at a 60 pc resolution in the J=2-1 transitions of 12CO, 13CO, and C18O as well as in the 1.3 mm continuum. Molecular gas and dust are mainly…
Spitzer Space Telescope mid-infrared images of the radio galaxy Centaurus A reveal a shell-like, bipolar, structure 500 pc to the north and south of the nucleus. This shell is seen in 5.8, 8.0 and 24 micron broad-band images. Such a…
The $l=-1.2^{\circ}$ region in the Galactic center has a high CO $J$=3-2/$J$=1-0 intensity ratio and extremely broad velocity width. This paper reports the detection of five expanding shells in the $l=-1.2^{\circ}$ region based on the CO…
We investigate the star formation processes operating in a mid-infrared bubble N49 site, which harbors an O-type star in its interior, an ultracompact HII region, and a 6.7 GHz methanol maser at its edges. The 13CO line data reveal two…
W49N is a mini-starburst in the Milky Way and thus an ideal laboratory for high-mass star formation studies. Due to its large distance (11.1$_{-0.7}^{+0.9}$ kpc), the kinematics inside and between the dense molecular clumps in W49N are far…
We present near-infrared narrow-band images of the supernova remnant W49B, taken with the WIRC instrument on the Hale 200 inch telescope on Mt. Palomar. The 1.64 micron [Fe II] image reveals a barrel-shaped structure with coaxial rings,…
Massive stars form on different scales ranging from large, dispersed OB associations to compact, dense starburst clusters. The complex structure of regions of massive star formation, and the involved short timescales provide a challenge for…
We summarize our comprehensive gas surveys of some of the most luminous, deeply embedded (optically obscured) star formation regions in the Milky Way, which are the local cases of massive star clusters and/or associations in the making. Our…