THE STRUCTURE OF NGC 1976 IN THE RADIO RANGE
- US Naval Research Laboratory, Code 7210, Washington, DC 20375 (United States)
- Departmento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile)
High angular resolution radio continuum images of NGC 1976 (M42, Orion A) at {nu} = 330 MHz ({lambda} = 91 cm), 1.5 GHz (20 cm), and 10.6 GHz (2.8 cm) have been aligned, placed on a common grid, smoothed to common resolutions of 80'' (=0.16 pc at 420 pc) and 90'' (=0.18 pc) and compared on a position-by-position basis. The results are not consistent with a single value of T{sub e}. The best fit to the continuum data is a multi-layer model based on radio recombination line data with a monotonic variation, from T{sub e} = 8500 K in the higher intensity, more compact region at the rear of NGC 1976 to T{sub e} = 6000 K in the low-intensity, extended region in the foreground. An estimate of temperature fluctuations toward the peak from this model yields t{sup 2} = 0.003. This is a factor of 10 lower than fluctuation values from optical collisionally excited line data.
- OSTI ID:
- 22004215
- Journal Information:
- Astrophysical Journal, Vol. 744, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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