1. ARENA-2005 THE UPPER LIMIT TO THE EHE NEUTRINO FLUX FROM OBSERVATIONS OF THE MOON WITH KALYAZIN RADIO TELESCOPE. A.R.Beresnyak, R.D.Dagkesamanskiy, A.V.Kovalenko I.M.Zheleznykh

2. ARENA-2005 Contents of the talk 1. Some milestones on the way to SHE neutrino detection 2. Description of the Kalyazin experiment 3. Short discussion of our first results 4. Plans for the future

3. ARENA-2005 Some important milestones on the way to SHE neutrinos detection. 1961,1965 - G.Askaryan’s idea on negative charge excess of cascades in a dense dielectric medium and corresponding Cherenkov radio pulses expected. 1983 - G.A.Gusev and I.Zheleznykh propose Radio Antarctic Muon And Neutrino Detector (RAMAND project) with the antennas “listening” an ice massive. 1988 – I.Zheleznykh propose the RAdio Moon Hadron And Neutrino Detection (RAMHAND).

4. ARENA-2005 Some important milestones (cont.) 1989 - First estimates of the Moon target volume and the sensitivity of the large ground-based radio telescopes made by Dagkesamanskiy & Zheleznykh. 1996 - First search of the nanosecond pulses from the Moon with 64-meter radio telescope of the Parks Radio Observatory (T.Hankins, R.Ekers & J.D.O’Sullivan). 2000 – Excellent results in the SLAC laboratory experiment and the first results of the GLUE project presented at RADHEP-2000 by P.Gorham, D.Saltzberg and their colleagues.

5. ARENA-2005 The main parameters of our experiment - PRAO team started the monitoring of the Moon from 2002. Some of the first observations were made with our 22-meter dish, but the most fruitful results have been obtained with Kalyazin 64-meter radio telescope. - Multi-frequency feed system of Kalyazin 64-meter radio telescope is very important advantage. Indeed, delay of the signal at lower frequency due to dispersion in the Earth ionosphere could be used to separate the signal from the Moon from local interferences. - The main frequencies are 1.4 and 2.3 GHZ. - 2 different options of simultaneous multi-frequency observations. - trigger recording system register all suspicious events with 2 ns time resolution.

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7. The antenna beamwidths are ~11' at 1.4 GHz and ~7' at 2.3 GHz. The expected events should be near the limb of the Moon, so the pointing was at 14' apart from the center of the Moon Position of the antenna beams on the Moon

8. ARENA-2005 Receiver system block-scheme (option 1) Receiver system block-scheme (option 1)

9. ARENA-2005 Receiver system block-scheme (option 2)

10. ARENA-2005 1.4 GHz (LCP) 1.4 GHz (RCP) 2.3 GHz (RCP) 4.8 GHz (RCP) Example of the suspicious event (opt.1)

11. ARENA-2005 Our main results - Option 2 (3.5 times more sensitive) is used only after mid of 2004. - Corresponding thresholds were 13000 Jy (opt.1) and 3500 Jy (opt.2). - Today the total “live-time on the Moon” is slightly more than 60 hrs. - With this “exposition” we had not found any reliable radio pulse that could be considered as Cherenkov emission pulse. Our combined estimate of the upper limit to the extremely-high-energy neutrino flux (Astronomy Reports, Vol.49,No.2, 2005, p.127) is a little bit more conservative than GLUE’s one. Is it due to our less optimistic estimate of the effective target volume ? - Yes. or different slope adopted for neutrino spectrum above 10 20 eV ? - May be. or there are any other differences in the model parameters ? - May be.

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13. How to improve our estimates ? We consider the following ways: 1. Increasing the “live-time on the Moon” (i.e. make more and more observations). 2. Increasing the sensitivity (use wider receiver bandwidths and coincidence schemes). 3. Reduce the thresholds and use some kind statistic analisys of the suspicious events. 4. To use not only observations of the Moon with the large ground base radio telescopes, but also the other possible space targets.

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15. International cooperation The possible scheme of international cooperative observaions proposed by I.Zheleznykh in 1988. Such observations will be very useful: they improve sensitivity, increase the reliability of results, and even could help us to determine the direction to the UHE neutrino source.

16. ARENA-2005 That’s all. Many thanks to Organizing Committee for invitation and to all of you for your attention !

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