New Catalogs of Radio Compact HII Regions in the Milky Way

2008 ◽  
pp. 322-322
Author(s):  
Uriel Giveon ◽  
R. H. Becker ◽  
D. J. Helfand ◽  
R. L. White ◽  
M. J. Richter
Keyword(s):  
Milky Way ◽  
Hii Regions ◽  
Compact Hii Regions

14 years of 6.7 GHz periodic methanol maser observations towards G188.95+0.89

2019 ◽  
Vol 15 (S356) ◽  
pp. 393-394
Author(s):  
Martin M. Mutie ◽  
Paul Baki ◽  
James O. Chibueze ◽  
Khadija El Bouchefry
Keyword(s):  
Radio Telescope ◽  
Exponential Decay ◽  
Hii Regions ◽  
Monitoring Period ◽  
Methanol Maser ◽  
Spectral Components ◽  
Methanol Masers ◽  
Compact Hii Regions

AbstractWe report the results of 14 years of monitoring of G188.95+0.89 periodic 6.7 GHz methanol masers using the Hartebeesthoek 26-m radio telescope. G188.95+0.89 (S252, AFGL5180) is a radio-quiet methanol maser site that is often interpreted as precursors of ultra-compact HII regions or massive protostar sites. At least five bright spectral components were identified. The maser feature at 11.36 km s-1 was found to experience an exponential decay during the monitoring period. The millimetre continuum reveals two cores associated with the source.

scholarly journals ISOCAM 3-12 μm imaging of five galactic compact Hii regions

2001 ◽  
Vol 371 (1) ◽  
pp. 312-327 ◽  
Author(s):  
A. Zavagno ◽  
V. Ducci
Keyword(s):  
Hii Regions ◽  
Compact Hii Regions

scholarly journals The Youngest Star-Forming Regions in Galaxies: Giant Compact HII Regions and Protoglobular Clusters?

2001 ◽  
Vol 205 ◽  
pp. 224-227
Author(s):  
Jean L. Turner
Keyword(s):  
Dwarf Galaxy ◽  
Hii Regions ◽  
Starburst Galaxies ◽  
Mid Infrared ◽  
Infrared Observations ◽  
Star Forming ◽  
Bolometric Luminosity ◽  
Star Forming Regions ◽  
Young Clusters ◽  
Compact Hii Regions

Subarcsecond radio and infrared observations reveal a class of luminous, obscured, optically thick HII regions associated with extremely large young clusters in nearby starburst galaxies. VLA images show bright radio nebulae with ne ∼ 104 cm−3, densities characteristic of young Galactic compact HII regions. Excitation of the nebulae requires the presence of several thousand O stars within regions of 1-10 pc extent, corresponding to clusters containing 105–106 stars. The compact nebulae are also bright in the mid-infrared, and can for significant fractions of not only the total IR luminosity, but also the total bolometric luminosity, of the parent galaxies. The prototype for these “supernebulae” is the large, obscured cluster in the dwarf galaxy NGC 5253.

scholarly journals ISO Observations of Compact HII Regions in the Large Magellanic Cloud

1999 ◽  
Vol 190 ◽  
pp. 377-378
Author(s):  
A. Moneti ◽  
R. J. Laureijs ◽  
J.M. van der Hulst ◽  
F. Israel ◽  
P.P. van der Werf
Keyword(s):  
Star Formation ◽  
Hii Regions ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
First Results ◽  
Reflection Nebulae ◽  
Compact Hii Regions

With the detection of strong PAH features and H2 emission in selected knots of the N159, N11A, and 30 Dor regions in the LMC, we present the first results of a study that is part of a coordinated Guaranteed Time ISO programme to investigate star formation in the Magellanic Clouds. The PAH features have different ratios than the ones in Galactic reflection nebulae.

scholarly journals 7 mm continuum observations of ultra compact HII regions

2009 ◽  
Vol 507 (3) ◽  
pp. 1467-1473 ◽  
Author(s):  
P. Leto ◽  
G. Umana ◽  
C. Trigilio ◽  
C. S. Buemi ◽  
S. Dolei ◽  
...  
Keyword(s):  
Hii Regions ◽  
Compact Hii Regions

Observations of the 1→0 Transition of CO Towards Southern HII Regions

1982 ◽  
Vol 4 (4) ◽  
pp. 434-440 ◽  
Author(s):  
J. B. Whiteoak ◽  
Robina E. Otrupcek ◽  
C. J. Rennie
Keyword(s):  
Radio Telescope ◽  
Molecular Cloud ◽  
Milky Way ◽  
Line Emission ◽  
Hii Regions ◽  
Hii Region ◽  
Giant Molecular Cloud ◽  
Molecular Lines ◽  
Csiro Division

The 4-m radio telescope of the CSIRO Division of Radiophysics at Epping is being used to survey the line emission associated with the 1→0 transition of CO (rest frequency 115.271 GHz) in the southern Milky Way. The programme includes mapping the CO distribution across giant molecular-cloud/HII-region complexes. As a first stage the emission has been observed towards bright southern HII regions. These results will not only serve as a basis for future extensive mapping but will also provide data which is directly comparable with observations of other molecular lines that have been made towards the HII regions.

scholarly journals The spiral structure of our Milky Way

2012 ◽  
Vol 8 (S292) ◽  
pp. 106-106
Author(s):  
L. G. Hou ◽  
J. L. Han
Keyword(s):  
Milky Way ◽  
Spiral Structure ◽  
Hii Regions ◽  
Giant Molecular Clouds ◽  
Constant Weight ◽  
Spiral Arms ◽  
Flat Rotation Curve ◽  
Methanol Masers ◽  
The Masses ◽  
Excitation Parameters

AbstractThe spiral structure of our Milky Way has not yet been well outlined. HII regions, giant molecular clouds (GMCs) and 6.7-GHz methanol masers are primary tracers for spiral arms. We collect and update the database of these tracers which has been used in Hou et al. (2009) for the spiral arms.The new database consists of ∼ 2000 HII regions, ∼ 1300 GMCs and ∼ 800 methanol masers (6.7 GHz). If the photometric or trigonometric distance for any tracer is available from the literature, we will adopt it. Otherwise, we have to use the kinematic distance. We modify the VLSR according to the newly determined solar motions (U0 = 10.27 km s−1, V0 = 15.32 km s−1 and W0 = 7.74 km s−1, Schönrich et al. 2010), then calculate the kinematic distances with a flat rotation curve (R0 = 8.3 kpc, θ0 = 239 km s−1, Brunthaler et al. 2011). Very important step is that we weight tracers according to the excitation parameters of HII regions or the masses of GMCs, and a constant weight for masers. All three kinds of tracers are used together to outline the spiral structure (Fig. 1). A contour and gray map is constructed after we made a Gaussian extension for the tracers with the amplitude of weighting parameter.

Erratum - Optical Radio and Infrared Observations of Compact HII Regions - Part Five - the Hourglass in M8

1986 ◽  
Vol 92 ◽  
pp. 682
Author(s):  
C. E. Woodward ◽  
J. L. Pipher ◽  
H. L. Helfer ◽  
S. Sharpless ◽  
A. Moneti ◽  
...  
Keyword(s):  
Hii Regions ◽  
Infrared Observations ◽  
Compact Hii Regions
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