PoS(10th EVN Symposium)097

http://pos.sissa.it reAlike Licence. from the Earth. Here we describe a cosmic rays. Interactions of cosmic rays found evidence for the Greisen-Zatsepin- Meeting: VLBI and newthe generation of escope, which produces limits comparable I telescopes in coincidence would eliminate e Askar’yan charge excess mechanism can d that neutrino interactions in the can smic microwave background are expected to asure the width of the Cherenkov cone

Manchester 1

the Creative Commons the Creative Attribution-NonCommercial-Sha , Alan Macfarlane, Owen Mills and Lucio Piccirillo Lucio Mills and Owen Macfarlane, , Alan 1 ralph.spencer@.ac.uk give rise to showers of particles, which through th preliminary experiment at 21 cm with the Lovell tel with with energies of greater than ~0.05 ZeV the with co produce high energy neutrinos. It has been suggeste produce Cherenkov emission in the , detectable with those from other radio telescopes. Use of VLB Recent Recent measurements by the Pierre Auger array have Kuzmin (GZK) cut off in the high energy spectrum of local impulsive RFI and also possibly be able to me Copyright owned by the author(s) owned of the Copyrightby terms under

10th EuropeanVLBI Network Symposium and EVN Users radio arrays Manchester, UK September 20-24

Ralph Ralph Spencer Schoolof Physics andAstronomy, The University of La Luna: Lovell Attempts LUnar Neutrino LUnar Attempts Lovell Luna: La Acquisition Oxford Rd., Manchester M13 9PL, UK E-mail:

PoS(10th EVN Symposium)097 Speaker Name taken. taken. None of these experiments larization larization channels. The interaction subsequently been undertaken. The s gamma-ray bursts, active galactic eV) is around 36 [12]km and so the tulating tulating that the emission could be downloading data to disk from the rs rs in dense media could emit coherent the potential to be an important tool in in tool an important to be potential the d to have greatly increased sensitivity 21 ll ll telescope arose in 2009 and 2010, as Neutrinos with energies in excess of lso be used to look for radio emissions 32 MHz bandwidth. Data were recorded azin azin [9], WSRT [10], l upper limits have been found. Future m m the cosmic microwave background. A e Moon. In 1989 Dagkesamanskii and ies ies of radio observations of pulses from r. r. The radiation is expected to be linearly s s were taken on 3 Nov 2009 and again in a d onto the lunar surface could be used to atmosphere atmosphere then resulted (see e.g. Spencer m m the moon by 2 degrees for comparison. c min. The total observing time on the limb Greisen and independently by Zatsepin and the the moon. The pulses are broad band and so elic elic particles [1]. UHE neutrinos can also be s as they are produced as a by-product of the

z, z, the next used the (GLUE) [8]Goldstone at eV =10 6 simultaneous and clear events were found wo circularly polarised channels. Observations Observations channels. polarised circularly wo

eV. Subsequent decay of the pions and muons 2 19

A A number of experiments using radio telescopes have An An opportunity for trial observations with the Love The study of ultra-high-energy (UHE) neutrinos (UHE) has of ultra-high-energy Thestudy In In 1962 Askar’yan [4] suggested that particle showe eV are predicted to be produced by processes such a 20 erenkov erenkov radiation at radio frequencies. A whole ser found definitive pulses from the moon, though usefu observations planned with LOFAR and SKA are expecte [10]. detect comic-ray-induced particle showers within th Zheleznykh proposed that the same mechanism could a 1.8-2.2 GHz, and further experiments using the Kaly ATCA [11] and the EVLA (RESUN) [12] were also under cosmic cascade showers produced in the Earth’s 1969 [5]). He also suggested that detectors droppe from the Moon due to UHE [6]. telescopes radio Earth-bound using by detected neutrino interactions, pos first was by the Parkes telescope [7] at MH 1.2-1.7 part of an undergraduate MPhys project. Observation more extensive run on 11 May 2010 at 1418 MHz with on a Tektronix TDS1012 oscilloscope on LH and RH po length of at neutrinos the expected (~energies 1 Z the study of many energetic astronomical phenomena. 10 results in a strong flux of high energy neutrinos. energy flux high of a strong in results Č are expected to be bandwidth limited in our receive signals are expected to come only from the limb of polarised and equal therefore give insignals our t were made at the centre, on the limb and offset fro Note that the beam width of the telescope was 10 ar of the moon was 4.3 hrs, however a slow response in oscilloscope oscilloscope resulted in a live-time total of 1 hr. 2. Our Observations 2. Our 1.Introduction 1.Introduction Short title Kuzmin Kuzmin [2,3] for proton energies above 10 interaction interaction between UHE cosmic rays and photons fro cut-off in the cosmic ray spectrum was predicted by used to probe the standard model of particle physic nuclei, topological defects and decays of massive r PoS(10th EVN Symposium)097

Z 0.024 = level of the Speaker Name E E in ZeV Ez . This effectively . This effectively -1 MHz -1 Vm V, the horizontal scale has a total a total has V, scale the horizontal neutrino energy energy neutrino vs se from the moon is sr) 2 dB above the background sky and with a sec sec vel was 0.01 vel area, area, the receiver noise temperature and the

d off the moon, i.e. limited by local impulsive

e telescope of 0.4 ZeV. ZeV. of 0.4 e telescope (in Km (in

A 3 length of 2.5 length of is the energy of the neutrino in ZeV. The rms noise

Z E Plot of effective aperture aperture effective of Plot Typical pulse profile. The vertical scales is in m in is scales The vertical Typical profile. pulse [12] where Figure 2 Figure -1

MHz Figure 1 Figure The expected peak electric field of a Cherenkov pul

-1 Vm sets a lower limit to the energy detectable with th detectable with theto energy limit sets a lower interference. A typical pulse is shown in figure 1. in figure shown is pulse typical A interference. Short title from a total rate of 1800 /hr – similar both on an Lovell Lovell receiver depends on the telescope effective bandwidth. The signal on the limb of the moon was 5 32 MHz bandwidth the resulting 4-sigma detection le 4-sigma bandwidth resulting the 32 MHz PoS(10th EVN Symposium)097

events 3 Speaker Name ay on the Earth of the lunar limb (for a π . 259-261.. f observing time of several hundred is much lower at around 0.01 ZeV. roduct of the total cross sectional area, roduct of the area, total cross sectional ope for ope a search for events on neutrino sible – either by the use of a lower 90% confidence level upper limit for 50 ations, allowing for the intrinsic radio expected to expected inresult apattern beam with limits to neutrino rates. More efficient moon, and so there is the possibility that it recording techniques will however be oise oise background, and a bespoke recording lescopes lescopes available in VLBI would be able he best coincidence regime as regime he best well coincidence as being from the RESUN experiment [12]. experiment the RESUN from scope scope covers 10/30 and hence surface roughness. roughness. surface hence and escope, both escope, at the ofexpense a higher lower -1 ments ments give an upper limit of 2.2 x 10 ations ations use Monte-Carlo simulations, e.g. [13]. lunar [12,13]. the 2 shows Figure regolith the P Lett. sr

. 78-81. -1 -1 4 453-461. 4 yr if isotropic), and the detection probability which -2 -2 . 441-443.. π 14 . 748-750. 16 radians or 8.5 degrees at 21 cm. A global VLBI arr

-0.22 λ Z 1 ( ) tA E , compared with a limit of 1 km a limit with , compared 2.3 -1

sr < -1 -1 F Refraction Refraction by the surface irregular of the ismoon Our showed that experiment use of the telesc Lovell The effective The aperture the depends effective of moon on the p yr -2 -2 an rms width ~0.2 2.1 Scattering 2.1 Scattering [4] Askar’yan, G.A. 1962. Phys. JETP. Sov. [3] G.T.Zatsepin, Kuzmin, V.A. 1966.JETP Lett. would subtend a maximum angle of 1.9 degrees at the a VLBI array could begin to measure the scattering scattering the measure to begin array could a VLBI where t is the integration total time. Our measure References References [1] Ghandi R., 2000, Proc. Nucl. Phys. Suppl. 91, [2] Greisen, K. 1966. Phys. Rev. Lett. 3.Conclusions Short title 10 arc min beam on a 30 arc min diameter moon). The by is given flux neutrino depends depends on details of the interactions. Most calcul However However Gayley et al. [14] derive analytic approxim by the andspectrum irregular of surface scattering results for our measurements assuming that the tele km [5] Spencer, R. E.,1969, 222, 460-461 [6] Dagkesamanskii, R.D. Zheleznykh, I.M. 1989. JET able able to study some details of the emission Multi-b the moon was feasible. However a large commitment o hours would be required to obtain competitive upper Coincidence techniques would reduce the impulsive n system could eliminate dead time. The 25-m class te to thecover atand moon 1.4 provide GHz, perhaps t required. observations observations could be made if the whole frequency, e.g. 408 MHz, or by using a smaller tel limb was vi energy limit above 1 ZeV. Note that the GZK energy the total solid angle of the neutrinos (4 PoS(10th EVN Symposium)097 Speaker Name 30.

127-133. t. Phys. Phys. 30,t. 318-332 01. 5 3 , 19301. ICRC, ICRC, Lódz 2009. st

[10] Scholten, O., et al., 2009, RevPhys 109Lett. [11] James, C. et al. 2009. Proc. of 31 the Short title [7] Hankins, T.H. et 1996,al.,MNRAS, 283, 1027-10 [8] et al.,Gorham 2004,Phys. Lett.Rev. 93, 0411 [9] Beresnyak et al., 2005, Reports.Astronomy 49, [14] K. et Gayley, al. 2009,ApJ, 706,1556-1570 . [12]Jaeger et al. 2010 Astropart. Phys. 34, 293-30 [13] James, C. W., Protheroe, R. J., 2009, Astropar