Distribution of compact HII regions in the galaxy and characteristics of their thermal regime

Astrophysics ◽  
1977 ◽  
Vol 12 (2) ◽  
pp. 183-187
Author(s):  
T. B. Pyatunina
Keyword(s):  
Thermal Regime ◽  
Hii Regions ◽  
The Galaxy ◽  
Compact Hii Regions

scholarly journals ISO spectroscopy of compact HII regions in the Galaxy

2002 ◽  
Vol 381 (2) ◽  
pp. 571-605 ◽  
Author(s):  
E. Peeters ◽  
N. L. Martín-Hernández ◽  
F. Damour ◽  
P. Cox ◽  
P. R. Roelfsema ◽  
...  
Keyword(s):  
Hii Regions ◽  
The Galaxy ◽  
Compact Hii Regions

scholarly journals ISO spectroscopy of compact HII regions in the Galaxy

2002 ◽  
Vol 381 (2) ◽  
pp. 606-627 ◽  
Author(s):  
N. L. Martín-Hernández ◽  
E. Peeters ◽  
C. Morisset ◽  
A. G. G. M. Tielens ◽  
P. Cox ◽  
...  
Keyword(s):  
Hii Regions ◽  
The Galaxy ◽  
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 Observations of Interstellar CH at 9 cm Wavelength

1976 ◽  
Vol 29 (3) ◽  
pp. 211 ◽  
Author(s):  
FF Gardner ◽  
BJ Robinson ◽  
MW Sinclair
Keyword(s):  
Transition Temperature ◽  
Ground State ◽  
Molecular Clouds ◽  
Hii Regions ◽  
The Galaxy ◽  
Galactic Sources

The 9 cm ground-state lines of CH have been observed in southern galactic sources, mainly HII regions. The F = 0-1 transition at 3264 MHz has been detected in emission in 16 sources; the F = 1-1 transition at 3335 MHz has been seen in absorption in 5 sources and in emission in 2 others. Where the F = 1-1 transition is in absorption the transition temperature is positive and below about 100 K. The F = 0-1 transition is generally inverted, with a transition temperature between -10 and 0 K. The column densities of CH are in the vicinity of lO'4 cm-2, slightly below those for OH but many times those for H2CO. There is no correlation between apparent optical depths of CH and those for OH or H2CO absorption. There is also no enhancement of CH in the dense molecular clouds near the centre of the Galaxy.

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

scholarly journals Pulsars as a galactic population

1979 ◽  
Vol 84 ◽  
pp. 119-123
Author(s):  
Joseph H. Taylor
Keyword(s):  
Carbon Monoxide ◽  
Statistical Analysis ◽  
Supernova Remnants ◽  
Galactic Center ◽  
Hii Regions ◽  
The Sun ◽  
Disk Thickness ◽  
Galactic Population ◽  
The Galaxy

Recent pulsar surveys have increased the number of known pulsars to well over 300, and many of them lie at distances of several kpc or more from the sun. The distribution of pulsars with respect to distance from the galactic center is similar to other population I material such as HII regions, supernova remnants, and carbon monoxide gas, but the disk thickness of the pulsar distribution is rather greater, with <|z|>≈350 pc. Statistical analysis suggests that the total number of active pulsars in the Galaxy is a half million or more, and because kinematic arguments require the active lifetimes of pulsars to be ≲5×106 years, it follows that the birthrate required to maintain the observed population is one pulsar every ∼10 years (or less) in the Galaxy.

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