Observations of a new Class of Solar Radio Bursts at 1420 MHz
Abstract
We present very high temporal and spectral resolution, single baseline interferometric observations of perhaps a new class of solar radio bursts at 1420 MHz. The data presented here was obtained on 19:44 UT, September 13, 2005 using the Small Radio Telescope (SRT) in interferometric mode. This coincided with the presence of a very active sun spot group (region 10808), which produced more major flares than any other region in solar cycle 23. These bursts were observed about 20 minutes after a X1.5 flare from this region. The observations show 11 events within a span of about 8 seconds. Each event comprised a heavily modulated band of emission with a spectral slope of about -245.5 MHz/s. The duration of each event was between 10-15 ms and had up to eight individual blobs of emission. These blobs had a bandwidth in the range ~200-250 kHz, appeared every ~400 kHz and had typical duration of ~4-5 ms. We believe these are the first observations of such rapid and short bandwidth bursts at 1420 MHz. Our ability to observe these bursts stems from the very high temporal (512 micro sec) and spectral resolution (125 kHz) afforded by the SRT interferometer in the off-line correlation mode, and that the 1.125 km interferometer baseline was insensitive to the emission from the solar disc. The closest similar observations which we could locate in literature were reported by McConnell and Ellis (McConnell and Ellis, 1981, Solar Physics; McConnell 1982, 1983, Solar Physics) at frequencies about two orders of magnitude lower , 33-44 MHz.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMSH23A0344O
- Keywords:
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- 6924 Interferometry (1207;
- 1209;
- 1242);
- 6954 Radio astronomy;
- 7534 Radio emissions