A Thermal Source with Strong 1612 MHz OH Emission

1969 ◽  
Vol 1 (5) ◽  
pp. 211-212
Author(s):  
B. J. Robinson ◽  
W. M. Goss ◽  
R. N. Manchester
Keyword(s):  
Ground State ◽  
Hii Regions ◽  
Thermal Source ◽  
Strong Source ◽  
Galactic Longitude

During 1968 we have found at Parkes several types of emission in the lines of the 18 cm quadruplet of the ground-state OH molecule. This note describes a strong source of 1612 MHz emission near galactic longitude 331°.OH emission was originally detected in the vicinity of HII regions, and a search of a large number of HII regions showed that about a third had associated OH emission. This type of emission is usually strongest at 1665 MHz, and is also seen at 1667 MHz and weakly on one of the satellite lines.

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.

3.3 GHz Ground-State Transitions of CH towards Southern HII Regions–1. An Atlas of CH Profiles

1985 ◽  
Vol 6 (1) ◽  
pp. 6-33 ◽  
Author(s):  
J. B. Whiteoak ◽  
F. F. Gardner ◽  
Gwenyth A. Manefield ◽  
B. Höglund ◽  
L. E. B. Johansson
Keyword(s):  
Radio Telescope ◽  
Ground State ◽  
Hii Regions ◽  
State Transitions ◽  
Space Observatory ◽  
Onsala Space Observatory

SummaryThe Parkes 64-m radio telescope equipped with a 3 GHz maser on loan from the Onsala Space Observatory has been used to observe the three ground-state transitions of CH (at 3264, 3335 and 3349 MHz) towards a total of 74 HII regions, mostly at southern declinations. In this paper the regions and related characteristics are listed, and the CH spectra displayed.

scholarly journals Atlas of Main-line OH Masers in the Galactic Longitude Range 3° to 60°

1983 ◽  
Vol 36 (3) ◽  
pp. 417 ◽  
Author(s):  
JL Caswell ◽  
RF Haynes
Keyword(s):  
Star Formation ◽  
Circular Polarization ◽  
Galactic Plane ◽  
Hii Regions ◽  
Main Line ◽  
Late Type ◽  
Circumstellar Shells ◽  
Many Sources ◽  
First Time ◽  
Galactic Longitude

We tabulate all 55 OH main-line masers discovered to date in the galactic plane between longitude 3� and 60�. For most of these we show current spectra, which have been taken with the Parkes 64 m radio telescope, in both senses of circular polarization on the 1665 MHz and/or 1667 MHz transitions; for some sources we give new position estimates, and several sources are reported for the first time. We discuss many sources individually and note that while most of the main-line OH masers probably pinpoint compact HII regions and sites of current star formation, a few appear to be unusual varieties occurring in circumstellar shells, possibly associated with late-type stars.

scholarly journals Survey of OH Masers at 1665 MHz. II. Galactic Longitude 340o to the Galactic Centre

1983 ◽  
Vol 36 (3) ◽  
pp. 361 ◽  
Author(s):  
JL Caswell ◽  
RF Haynes
Keyword(s):  
Ground State ◽  
Galactic Plane ◽  
Line Emission ◽  
State Transitions ◽  
Galactic Centre ◽  
Emission Sources ◽  
Type I ◽  
Type Ii ◽  
Formation Type ◽  
Galactic Longitude

The galactic plane from longitude 340� through the galactic centre to longitude + 2� has been searched for OH on the 1665 MHz transition. Forty-nine OH maser emission sources were detected and these have now been studied on all four OH ground-state transitions. Most of the masers are associated with regions of star formation (type I) while three may be examples of late-type stars (type II OH/IR) with unusually strong main-line emission

scholarly journals A Search for Recombination Line Emission from the Galactic Equator at 408 MHz

1976 ◽  
Vol 29 (5) ◽  
pp. 419 ◽  
Author(s):  
MJ Batty
Keyword(s):  
Surface Brightness ◽  
Thermal Emission ◽  
Line Emission ◽  
Hii Regions ◽  
Line Of Sight ◽  
Recombination Line ◽  
Upper Limits ◽  
Low Surface Brightness ◽  
Lower Limits ◽  
Galactic Longitude

A search for H 2520( recombination line emission was made by scanning the galactic equator region using the Molonglo radio telescope. Upper limits were established over the range of galactic longitude accessible to the instrument. For the region III ;S 40�, estimates of the background thermal continuum brightness temperature were used to derive lower limits of ~ 2000 K for the electron temperature of the gas along the line of sight. Lower limits for the electron density obtained by considering probable non-LTE effects suggest that the thermal emission over this range is due to low surface brightness HII regions. The observed H 2520( upper limit averaged over the range 270� ;S I ;S 320� just admits the line intensity calculated by Shaver (1975) for the cold cloud component of the general interstellar medium.

Spectra of the 10-01 Transition of Sulfur Monoxide in Interstellar Clouds

1980 ◽  
Vol 87 ◽  
pp. 71-76
Author(s):  
O.E.H. Rydbeck ◽  
Å. Hjalmarson ◽  
G. Rydbeck ◽  
J. Elldér ◽  
E. Kollberg ◽  
...  
Keyword(s):  
Ground State ◽  
Molecular Clouds ◽  
Zeeman Splitting ◽  
Hii Regions ◽  
Interstellar Clouds ◽  
Dark Clouds ◽  
Isotopic Species ◽  
Fractional Abundance ◽  
Sulfur Monoxide ◽  
The Magnetic Field

Emission from SO towards a number of HII regions and molecular clouds with embedded energy sources has been reported by several authors (e.g., Gottlieb et al. 1978; Clark et al. 1978; Wannier and Phillips 1977; and references therein; cf. also Loren et al., 1974; Loren et al. 1975; Lada et al. 1974). Transitions observed include the 45→44, 43→32, 32→21, 23→12, 22→11, 12→11, and 10→01, with the latter (to the ground state) seen only in Sgr B2. Recently Rydbeck et al. (1980) have detected SO in cold, dark clouds and have made the first astronomical measurements of the 10→01 transition in a variety of sources, including the corresponding 34SO line. The latter authors find that the 10→01 transition of SO is an excellent tracer of structure in dark clouds, and they discuss the fractional abundance [SO]/[H2] on the basis of column densities derived from observations of the two isotopic species. They also set limits to the magnetic field strength in dark clouds from the absence of observed Zeeman splitting. We shall provide here additional spectra and information on observing procedures, and shall discuss the rest frequencies for the SO and 34SO 10→01 transitions.

scholarly journals Ground-state cooling of mechanical resonators by quantum reservoir engineering

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Muhammad Tahir Naseem ◽  
Özgür E. Müstecaplıoğlu
Keyword(s):  
Laser Cooling ◽  
Ground State ◽  
Physical Mechanism ◽  
Quantum Information Processing ◽  
Reservoir Engineering ◽  
Thermal Source ◽  
Mechanical Resonators ◽  
Quantum Ground State ◽  
Standard Laser ◽  
Ground State Cooling

AbstractGround-state cooling of multiple mechanical resonators becomes vital to employ them in various applications ranging from ultra-precise sensing to quantum information processing. Here we propose a scheme for simultaneous cooling of multiple degenerate or near-degenerate mechanical resonators to their quantum ground-state, which is otherwise a challenging goal to achieve. As opposed to standard laser cooling schemes where coherence renders the motion of a resonator to its ground-state, we consider an incoherent thermal source to achieve the same aim. The underlying physical mechanism of cooling is explained by investigating a direct connection between the laser sideband cooling and “cooling by heating”. Our advantageous scheme of cooling enabled by quantum reservoir engineering can be realized in various setups, employing parametric coupling of a cooling agent with the target systems. We also discuss using non-thermal baths to simulate ultra-high temperature thermal baths for cooling.

scholarly journals THE SINO-GERMAN λ6 CM POLARIZATION SURVEY OF THE GALACTIC PLANE: A SUMMARY

2013 ◽  
Vol 23 ◽  
pp. 82-91 ◽  
Author(s):  
J. L. HAN ◽  
W. REICH ◽  
X. H. SUN ◽  
X. Y. GAO ◽  
L. XIAO ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Interstellar Medium ◽  
Radio Telescope ◽  
Supernova Remnants ◽  
Galactic Plane ◽  
High Sensitivity ◽  
Hii Regions ◽  
Galactic Latitude ◽  
Galactic Longitude ◽  
Individual Objects

We have finished the λ6 cm polarization survey of the Galactic plane using the Urumqi 25 m radio telescope. It covers 10° ≤ l ≤ 230° in Galactic longitude and |b| ≤ 5° in Galactic latitude. The new polarization maps not only reveal new properties of the diffuse magnetized interstellar medium, but also are very useful for studying individual objects such as HII regions, which may act as Faraday screens with strong regular magnetic fields inside, and supernova remnants for their polarization properties and spectra. The high sensitivity of the survey enables us to discover two new SNRs G178.2–4.2 and G25.3–2.1 and a number of HII regions.

Amplification and Absorption of the 9 cm2Π, J = ½ A-Doublet Lines of Interstellar CH

1974 ◽  
Vol 2 (5) ◽  
pp. 253-255 ◽  
Author(s):  
F. F. Gardner ◽  
B. J. Robinson
Keyword(s):  
Ground State ◽  
Hii Regions ◽  
Galactic Centre

Following the detection of the 9 cm ground-state triplet of CH by Rydbeck et al. (1973), preliminary observations at the CH frequencies were made with the Parkes 64-m telescope (beamwidth ∼6′ arc) in December 1973 and January 1974. We have detected the CH lines in many galactic HII regions and in the direction of the galactic centre.

scholarly journals On the nomenclature of diffuse fragmentary objects

1982 ◽  
Vol 64 ◽  
pp. 207-210
Author(s):  
P. Polechova
Keyword(s):  
Molecular Clouds ◽  
Beam Width ◽  
Hii Regions ◽  
Decimal Digit ◽  
Galactic Latitude ◽  
Wide Range ◽  
Half Power ◽  
5 Ghz ◽  
Galactic Longitude ◽  
Reflection Nebulae

AbstractFor the purpose of Cataloguing diffuse objects in a wide range of dimensions, two alternative proposals are presented.Problems similar to those discussed in connection with the nomenclature of optical HII-regions may occur with any diffuse objects such as molecular clouds, large reflection nebulae, HI-regions, and, of course, radio HII-regions.The radio HII-regions are most commonly designated by the galactic numbers “G”. The galactic longitude forms the first part of this number, the galactic latitude the second part, both parts being usually accurate to the first decimal digit and separated by the sign of latitude. This system (also used sometimes for optical objects) was introduced by Mezger and Henderson (1967) in a survey at 5 GHz, with a half power beam width of the telescope of about 6'. The angular dimensions of their objects were in the range from 3 to 11'.

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