scholarly journals The Trapezium Radio Cluster of the Orion Nebula

1989 ◽  
Vol 120 ◽  
pp. 333-338
Author(s):  
Guido Garay
Keyword(s):  
Radio Sources ◽  
Orion Nebula ◽  
Galactic Clusters ◽  
Dense Group

Abstract.We review the characteristics and discuss the nature of a dense group of compact radio sources found projected toward the Trapezium cluster of the Orion nebula. There are twenty-six radio sources, with flux densities greater than 2 mJy, clustered within a region of 35” radius around θ1C Orionis, the most luminous star of the Trapezium. The density of radio objects, of 1.4×104 pc-3, is extraordinarily high, about a thousand times greater than the density of stars in typical galactic clusters.

COMPACT CONTINUUM RADIO SOURCES IN THE ORION NEBULA

1982 ◽  
Vol 395 (1 Symposium on) ◽  
pp. 204-209 ◽  
Author(s):  
J. M. Moran ◽  
G. Garay ◽  
M. J. Reid ◽  
R. Genzel ◽  
P. T. P. Ho
Keyword(s):  
Radio Sources ◽  
Orion Nebula ◽  
Continuum Radio

Compact continuum radio sources in the Orion Nebula

1987 ◽  
Vol 314 ◽  
pp. 535 ◽  
Author(s):  
Guido Garay ◽  
James M. Moran ◽  
Mark J. Reid
Keyword(s):  
Radio Sources ◽  
Orion Nebula ◽  
Continuum Radio

scholarly journals A VLA SURVEY FOR FAINT COMPACT RADIO SOURCES IN THE ORION NEBULA CLUSTER

2016 ◽  
Vol 831 (2) ◽  
pp. 155 ◽  
Author(s):  
Patrick D. Sheehan ◽  
Josh A. Eisner ◽  
Rita K. Mann ◽  
Jonathan P. Williams
Keyword(s):  
Radio Sources ◽  
Orion Nebula

scholarly journals Emission Nebulae as Radio Sources

1956 ◽  
Vol 9 (2) ◽  
pp. 218 ◽  
Author(s):  
BY Mills ◽  
AG Little ◽  
KV Sheridan
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Radio Telescope ◽  
Optical Data ◽  
Radio Sources ◽  
Pencil Beam ◽  
Orion Nebula ◽  
Average Electron Density ◽  
Average Electron ◽  
Bright Emission

Attempts have been made to detect 14 bright emission nebulae at a wavelength of 3?5 m using a pencil-beam radio telescope with a beamwidth of 50 min of arc. Of these nebulae, six were probably observed in emission, seven were undetectable, and one, NGC 6357, was observed in absorption; radio isophotes were obtained for NGC 2237 and NGC 3372. Radio and optical data have been combined to estimate electron densities, masses, and sometimes the electron temperature of many of the nebulae. Values range from an electron density of 3 cm?3 and a mass of 3�10. solar masses for the outer regions of the 30 Doradus complex to an average electron density of 500 cm?3 and a mass of 20 solar masses for the Orion Nebula. Temperatures generally appear to be in the neighbourhood of 10,000 �K, except in the case of NGC 6357, for which 6500 �K is estimated.

scholarly journals THE POPULATION OF COMPACT RADIO SOURCES IN THE ORION NEBULA CLUSTER

2016 ◽  
Vol 822 (2) ◽  
pp. 93 ◽  
Author(s):  
J. Forbrich ◽  
V. M. Rivilla ◽  
K. M. Menten ◽  
M. J. Reid ◽  
C. J. Chandler ◽  
...  
Keyword(s):  
Radio Sources ◽  
Orion Nebula

scholarly journals Radio Observations of Hii Regions in M33

1974 ◽  
Vol 60 ◽  
pp. 227-228
Author(s):  
F. P. Israel ◽  
P. C. van der Kruit
Keyword(s):  
Radio Telescope ◽  
Hii Regions ◽  
Radio Sources ◽  
Orion Nebula ◽  
Radio Observations ◽  
Continuum Radiation ◽  
The Continuum

The Westerbork Synthesis Radio Telescope was used to map the continuum radiation of M33 at 1415 MHz. Of 67 radio sources with fluxes S> 1.8 mJy (3σ), 60% coincide with Hα sources. These are all intrinsically stronger than 4 × the Orion nebula, i.e., they are giant Hiiregions. The two strongest sources, NGC 604 (58 mJy) and NGC 595 (20 mJy), are similar to W51.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

The combined Herstmonceux Cambridge Program of optical positions of radio sources

1978 ◽  
Vol 48 ◽  
pp. 155-166 ◽  
Author(s):  
A. N. Argue ◽  
E. D. Clements ◽  
G. M. Harvey ◽  
C. A. Murray
Keyword(s):  
Standard Error ◽  
Unit Weight ◽  
Radio Sources

SummaryAGK3-based optical positions are presented for 38 counterparts of radio sources selected from the catalogue of Elsmore & Ryle. The measurements were made from plates taken with the 13-inch Astrograph, the 26-inch refractor and the 2.5 m (INT) reflector at Herstmonceux, and the 17-inch Schmidt at Cambridge. The standard error for a mean position of unit weight is 0”.11, and the weights range from 3.0 for the brightest sources to 0.5 for the faintest. Comparison with the radio positions shows no significant differences. The effects of applying the Brorfelde corrections to AGK3 are discussed.

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