scholarly journals Recombination Line Survey of Galactic H II Regions.

1967 ◽  
Vol 72 ◽  
pp. 824
Author(s):  
E. C., III Reifenstein ◽  
T. L. Wilson ◽  
B. F. Burke ◽  
P. G. Gomez
Keyword(s):  
H Ii Regions ◽  
Recombination Line ◽  
Line Survey

A hydrogen and helium radio recombination-line survey of galactic H II regions at 10 GHz

1979 ◽  
Vol 229 ◽  
pp. 524 ◽  
Author(s):  
S. M. Lichten ◽  
L. F. Rodriguez ◽  
E. J. Chaisson
Keyword(s):  
H Ii Regions ◽  
Recombination Line ◽  
Radio Recombination Line ◽  
Line Survey

scholarly journals The UM/CTIO Magellanic Cloud Emission-line Survey

1999 ◽  
Vol 190 ◽  
pp. 28-31 ◽  
Author(s):  
R. Chris Smith ◽  
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Supernova Remnants ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
H Ii Regions ◽  
Deep Imaging ◽  
Small Scales ◽  
Nearby Galaxies ◽  
Line Survey

The Magellanic Clouds are unique in providing sites to study the interstellar medium (ISM) and its components at all scales. To promote the pursuit of such studies, we have begun the Magellanic Cloud Emission-line Survey (MCELS), a deep imaging survey of both of these nearby galaxies in the emission of Hα, [S II], and [O III]. The emission-line images will be used in detailed optical and multiwavelength studies of H II regions, supernova remnants, planetary nebulae, superbubbles, and supergiant shells. Together with parallel surveys at other wavelengths, this survey will provide the foundation upon which to build a deeper understanding of the ISM in the Clouds and other galaxies, from small scales (~1 pc) all the way up to global scales. We present a sample of recent and current work using the MCELS dataset.

Recombination-line and continuum observations of compact H II regions at 10.5 GHz

1976 ◽  
Vol 81 ◽  
pp. 512 ◽  
Author(s):  
M. R. Viner ◽  
J. N. Clarke ◽  
V. A. Hughes
Keyword(s):  
H Ii Regions ◽  
Recombination Line

scholarly journals A Southern Hemisphere Ammonia Survey

1987 ◽  
Vol 115 ◽  
pp. 66-66
Author(s):  
W. L. Peters ◽  
J. R. Forster ◽  
F. F. Gardner ◽  
J. B. Whiteoak ◽  
T.B.H. Kuiper
Keyword(s):  
Spectral Line ◽  
Southern Hemisphere ◽  
The Other ◽  
H Ii Regions ◽  
Preliminary Survey ◽  
Antenna Beam ◽  
Different Types ◽  
Line Survey ◽  
Compact Sources

A spectral line survey for interstellar NH3 is being carried out using the 64-m telescopes at Parkes and Tidbinbilla. Both telescopes are equipped with K-band masers yielding system temperatures below 100 K. The preliminary survey was to be made with the Parkes antenna (beam = 1.5′ arc) with follow-up mapping of the more interesting sources at Tidbinbilla (beam = 0.9′ arc). Sources have in general been H II regions from the H2CO surveys made at Parkes. Approximately 70 sources (out of a target of (∼ 100) have been observed simultaneously in the metastable (1,1), (2,2) and (3,3) transitions. The (1,1) line has been detected in about 70% of the sources surveyed. The other lines which involve higher excitation are detected primarily in the more compact sources, particularly those associated with OH and H2O masers. Examples are given of spectra for different types of source.

scholarly journals A Survey of Recombination-line Abundances in Planetary Nebulae and H II Regions

2003 ◽  
Vol 209 ◽  
pp. 383-384 ◽  
Author(s):  
Y. G. Tsamis ◽  
M. J. Barlow ◽  
X.-W. Liu ◽  
I. J. Danziger
Keyword(s):  
Planetary Nebulae ◽  
Magellanic Cloud ◽  
H Ii Regions ◽  
Recombination Line ◽  
Large Aperture

We have derived C, N and O abundances, relative to H, using optical recombination lines (ORLs), for a number of galactic planetary nebulae and for three Magellanic Cloud PNe (LMC N66, N141, SMC N87) and compared them with the corresponding abundances derived from collisionally-excited lines (CELs). Our goal was to investigate the fact that PNe ORL abundances are in most cases larger than those obtained from CELs. Our scanning, long-slit observations were combined with large-aperture IUE, IRAS and ISO data to yield integrated abundances for more than half of our target objects.

scholarly journals The HI/OH/Recombination line survey of the inner Milky Way (THOR)

2016 ◽  
Vol 595 ◽  
pp. A32 ◽  
Author(s):  
H. Beuther ◽  
S. Bihr ◽  
M. Rugel ◽  
K. Johnston ◽  
Y. Wang ◽  
...  
Keyword(s):  
Milky Way ◽  
Recombination Line ◽  
Line Survey

scholarly journals THOR: The H i, OH, Recombination line survey of the Milky Way

2015 ◽  
Vol 580 ◽  
pp. A112 ◽  
Author(s):  
S. Bihr ◽  
H. Beuther ◽  
J. Ott ◽  
K. G. Johnston ◽  
A. Brunthaler ◽  
...  
Keyword(s):  
Milky Way ◽  
Recombination Line ◽  
Line Survey

scholarly journals UNTANGLING THE RECOMBINATION LINE EMISSION FROM H ii REGIONS WITH MULTIPLE VELOCITY COMPONENTS

2015 ◽  
Vol 810 (1) ◽  
pp. 42 ◽  
Author(s):  
L. D. Anderson ◽  
L. A. Hough ◽  
TREY V. Wenger ◽  
T. M. Bania ◽  
Dana S. Balser
Keyword(s):  
Line Emission ◽  
H Ii Regions ◽  
Recombination Line

scholarly journals G−0.02−0.07, the compact H ii region complex nearest to the galactic center with ALMA

2019 ◽  
Vol 71 (6) ◽  
Author(s):  
Masato Tsuboi ◽  
Yoshimi Kitamura ◽  
Kenta Uehara ◽  
Atsushi Miyazaki ◽  
Ryosuke Miyawaki ◽  
...  
Keyword(s):  
Shock Wave ◽  
Galactic Center ◽  
Emission Lines ◽  
Continuum Emission ◽  
Molecular Gas ◽  
H Ii Regions ◽  
Recombination Line ◽  
The Galaxy ◽  
H Ii Region ◽  
Absorption Features

Abstract We have observed the compact H ii region complex nearest to the dynamical center of the Galaxy, G−0.02−0.07, using ALMA in the H42α recombination line, CS J = 2–1, H13CO+J = 1–0, and SiO v = 0, J = 2–1 emission lines, and the 86 GHz continuum emission. The H ii regions HII-A to HII-C in the cluster are clearly resolved into a shell-like feature with a bright half and a dark half in the recombination line and continuum emission. The analysis of the absorption features in the molecular emission lines show that H ii-A, B, and C are located on the near side of the “Galactic center 50 km s−1 molecular cloud” (50MC), but HII-D is located on the far side of it. The electron temperatures and densities ranges are Te = 5150–5920 K and ne = 950–2340 cm−3, respectively. The electron temperatures in the bright half are slightly lower than those in the dark half, while the electron densities in the bright half are slightly higher than those in the dark half. The H ii regions are embedded in the ambient molecular gas. There are some molecular gas components compressed by a C-type shock wave around the H ii regions. From the line width of the H42α recombination line, the expansion velocities of HII-A, HII-B, HII-C, and HII-D are estimated to be Vexp = 16.7, 11.6, 11.1, and 12.1 km s−1, respectively. The expansion timescales of HII-A, HII-B, HII-C, and HII-D are estimated to be tage ≃ 1.4 × 104, 1.7 × 104, 2.0 × 104, and 0.7 × 104 yr, respectively. The spectral types of the central stars from HII-A to HII-D are estimated to be O8V, O9.5V, O9V, and B0V, respectively. These derived spectral types are roughly consistent with the previous radio estimation. The positional relation among the H ii regions, the SiO molecule enhancement area, and Class-I maser spots suggest that a shock wave caused by a cloud–cloud collision propagated along the line from HII-C to HII-A in the 50MC. The shock wave would have triggered the massive star formation.

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