Location of radio source at 35 GHz of 2145 UT 2 August 1972 burst
✍ Scribed by Hideo Ogawa; Kin-Aki Kawabata
- Publisher
- Springer
- Year
- 1975
- Tongue
- English
- Weight
- 922 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0038-0938
No coin nor oath required. For personal study only.
✦ Synopsis
The location of the radio source of a major burst at 2145 UT on 2 August 1972 is determined from observations undertaken by the 35 GHz solar interferometer at Nagoya. The location of the radio source coincides with an Ha brightening.
On 2 August 1972, a series of big solar flares occurred successively in the active region McMath 11976. Among these big flares, the last flare was accompanied by a very intense radio burst which attained its maximum flux density at 2145 UT. Observations of the intense radio burst were made by using the 35 GHz solar interferometer at Nagoya and have given a good opportunity to investigate a relationship between the optical flare and the radio burst.
The interferometer consists of eight fixed paraboloidal reflectors and eight plane reflectors. The eight plane reflectors on equatorial mountings are aligned along an east-west line with an equal spacing of 273 2. Each paraboloidal reflector with a Cassegrain feed system is fixed pointing downwards in such a way that the axis of the paraboloidal reflector coincides with the polar axis of the equatorial mounting of a respective plane reflector. The interferometer has a total span of 16.38 m (19132) and has a half power beam width of 1.4' at the meridian plane. The performance of the interferometer is described in some detail elsewhere (Kawabata et al., 1974).
On 2 August, a very active flare complex began with an He brightening which started at 1957 UT (Zirin and Tanaka, 1973). A modest X-ray burst and little radio emission occurred almost simultaneously with the He brightening. A series of intense radio bursts at 35 GHz (Castelli et al., 1973) started at 2036.5 UT and consisted of three bursts which attained their maximum flux densities at 2046, 2117 and 2145 UT respectively (Figure 1). The first radio burst followed the start of 15-60 keV X-ray burst observed on OSO-7 (Datlowe and Peterson, 1973;Chupp et al., 1973) and associated with a new brightening of He (Zirin and Tanaka, 1973). The 2145 UT radio burst was associated with another new brightening of He (Zirin and Tanaka, 1973) and an intense 60-120 keV X-ray burst observed on OSO-7. The 2145 UT X-ray burst below 60 keV can be seen only as a slight hump on an X-ray light curve.
The recording of the interferometer observations at Nagoya started at 2113 UT, just after the sunrise. The scanning data at 2127 UT first indicated the occurrence of the radio burst, although the data at that time were not good because a part of the interferometer was shadowed by trees. Good records of the radio burst were obtained after 2145 UT. The radio burst at 35 GHz attained maximum flux density of 955 sfu