HR: 0830h
AN: SM31C-1131    [PDF]
TI: Search for Exoplanetary Radio-Bursts in Decameter Wave Band: Statistical Enhancement of Sensitivity Under Severe Interference Conditions
AU: * Ryabov, V B
EM: riabov@fun.ac.jp
AF: Future University Hakodate, 116-2 Kamedanakano-cho, Hakodate, 041-8655 Japan
AU: Zarka, P
EM: Philippe.Zarka@obspm.fr
AF: DESPA, Observatoire de Paris-CNRS, Meudon, 92195 France
AU: Ryabov, B P
EM: rai@ira.kharkov.ua
AF: Institute of Radio Astronomy, 4 Krasnoznamennaya St., Kharkov, 61002 Ukraine
AB: Radio observations in decameter wave band are known to be subject to strong man-made interference signals that make difficult the detection of comparatively weak emissions of cosmic origin. The efficient methods of filtering out the interferences have been recently proposed that utilize the differences in characteristic time scales of the analyzed signals. Those methods, however, restrict the sensitivity of observations by imposing the limitation on the integration time in the post-detector signal analysis procedures. In this paper we demonstrate that effective sensitivity of such observations can be substantially increased by the statistical analysis of tails in the distribution function of short-time-integrated amplitudes. We apply the proposed signal processing technique to the analysis of data obtained in the recent experiment on the search for millisecond-type bursts from exoplanetary magnetospheres. The search was based on the conjecture that auroral regions of magnetized planets can be the sources of powerful radio bursts with characteristic timescales of the order of tens of milliseconds (similar to Jupiter S-burst storms). Although the power of the known by far planetary radio emissions in the Solar system seems to be insufficient for being detected from the distances greater than 2-3 parsec, the detection would be feasible for the so-called "hot Jupiters" (strongly magnetized giant planets located closely to their parent stars) mainly detected by far in optical searches for exoplanets. Our observations have been performed in 1999-2001 at the world-largest decameter radio telescope UTR-2 (Kharkov, Ukraine) used in combination with acousto-optical spectrometer as a receiver system. The observational targets included a list 20 candidate exoplanetary systems known from optical measurements and located not very far (within 15 parsec distance) from the Earth. The proposed statistical method has been tested and tuned with the data from several known radio pulsars recorded in parallel with observations of exoplanetary targets. Despite the absence of the positive result (detection of planetary bursts) by now, the proposed statistical technique allows obtaining an estimate from above on the expected radio flux densities from several known exoplanetary systems.
DE: 2794 Instruments and techniques
DE: 5757 Remote sensing
DE: 6954 Radio astronomy
DE: 6974 Signal processing
DE: 6994 Instruments and techniques
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting