E. Amaldi

Data Recordered by the Rome Room Temperature Gravitational Wave Antenna, during the Supernova SN 1987a in the Large Magellanic Cloud

The data recorded by the Rome room temperature gravitational-wave antenna during the Supernova SN 1987a have been analysed in connection with the Mont Blanc neutrino event. An energy innovation is observed which precedes by (1.4 ± 0.5) s the first observed neutrino arrival time with the probability of being accidental of 3 per cent. An estimation of the energy emitted as g.w. distributed over 4π and a frequency bandwidth of 1 kHz gives the figure of 2400 M⊙, which is abnormal according to standard views on g.w. Under the hypothesis that the time delay δt between the antenna signal and the first neutrino detected in the Mont Blanc tunnel is due only to the neutrino mass, the following mass value is derived from the observed δt = (1.4 ± 0.5) s: mνe ≤ (7.2 ± 1.3) eV.

Sensitivity of the Rome Gravitational Wave Experiment with the Explorer Cryogenic Resonant Antenna Operating at 2 K

We report on the results obtained with a cryogenic gravitational wave antenna equipped with a d.c. SQUID, operating at 2 K. During a period of a few days in April 1989 the measured noise temperature (for short bursts of gravitational waves) was Teff 7 mK corresponding to a sensitivity of hc 710-19. This result allows to improve the previously published upper limits for the rate of gravitational wave bursts.

Coincidences among the data recorded by the Baksan, Kamioka and Mont Blanc underground neutrino detectors, and by the Maryland and Rome gravitational-wave detectors during Supernova 1987 A

SummaryThe data recorded with the neutrino detectors at Mont Blanc, Kamioka, Baksan and with the gravitational-wave detectors in Maryland and Rome have been analysed searching for correlations associated with SN 1987 A, without presuming or excluding hypotheses for correlations due to neutrinos and gravitational waves. The statistical analysis has been based on a previous analysis that showed a correlation among Maryland, Rome and Mont Blanc with a probability to be accidental less than 10−5. Independent correlations are found during a period of one or two hours, around the Mont Blanc 5ν burst (2h 52 min 36 s UT), among the various sets of data: Mont Blanc-Baksan with a probability to be accidental of the order ofp∼4·10−3, Mont Blanc-Kamioka withp∼4·10−3, Maryland-Rome-Kamioka withp∼5·10−4, Maryland-Rome-Baksan withp∼5·10−2. It is remarkable that the events from all the neutrino detectors follow the signals from the g.w. detectors by a time of the order of 1/2 or 1 s. At present we will not give a physical interpretation of the observed correlations which have strong statistical significance.

Data analysis for a gravitational wave antenna with resonant capacitive transducer

SummaryWe present here a new approach which simplifies considerably the data analysis for gravitational-wave antennas equipped with resonant transducer, based on the representation of the antenna as two independent oscillators. In fact, we can apply to each of the two modes of these antennas the same data analysis procedures already in use for antennas with nonresonant transducer and then compute the coincidences between the outputs of the two modes. The results deduced by such a procedure are in good agreement with the experimental results from the data collected in March 1984 with our 2270 kg 5056 Al bar cooled at liquid-helium temperature (T=4.2 K). The performances of the algorithms are presented in terms of the effective noise temperatures and sensitivity to short bursts of gravitational waves. With our experimental values, obtained by using a FET amplifier, we get an instrumental sensitivityF(v) of 6 J/m2 Hz. We have also evaluated the sensitivity of the detector for monochromatic gravitational waves with frequencies in bandwidths of ≏0.4 Hz around the frequenciesv− andv+, for one month of observation:h0≏3·10−23.RiassuntoSi presenta un nuovo approccio che semplifica notevolmente l’analisi dei dati per antenne gravitazionali con trasduttore risonante, basato sulla rappresentazione dell’antenna come due oscillatori indipendenti. A ciascuno dei modi di tali antenne si applicano le procedure di analisi dei dati già usati per le antenne con trasduttore risonante e si calcolano quindi le coincidenze tra le uscite dei due modi. I risultati dedotti mediante tale procedura sono in buon accordo con i risultati sperimentali relativi ai dati raccolti nel marzo 1984 con la nostra sbarra di Al 5056 da 2270 kg raffreddata alla temperatura dell’elio liquido (T=4.2 K). Si presentano le prestazioni degli algoritmi in termini delle temperature efficaci di rumore e della sensibilità per brevi fiotti di onde gravitazionali. Con i nostri valori sperimentali, ottenuti usando un amplificatore a FET, si ha una sensibilità strumentaleF(v) di 6 J/m2 Hz. Si è anche calcolata la sensibilità del rivelatore per onde gravitazionali monocromatiche in bande di frequenza di circa 0.4 Hz attorno alle frequenzev− ev+, per un mese di ossevazione:h0≏3.·10−23.РезюмеПредлагается новый подход, котрый значительно упрощает анализ данных для антенн гравитационных волн с резонансным емкостным датчиком, основанный на представлении антенны в виде двух независимых осцилляторов. Мы можем применить к каждой из двух мод этих антенн процедуры анализа данных, которые ыже использовались для антенн с нерезонансными датчиками, а затем вычислить совпадения между результатами на выходе для двух мод. Результаты, полученные с помощью такой процедуры, хорошо согласуются с экспериментальными результатами, собранными в марте 1984 года с помощью 2270 кг 5056 Al антенны, охлажденной до температуры жидкого гелия (T=4.2 К). Описываются алгоритмы анализа, исходя из эффективных температур шума и чувствительности к коротким вспышкам гравитационных волн. Используя экспериментальные значения, полученные с помощью FET усилителя, мы определяем инструментальную чувствительностьF(v)≈6Дж/M2 Гц. Мы также оцениваем чувствительность детектора для монохроматических гравитационных волн в полосе частот 0.4 Гц вблизи частот,v− иv+ для одного месяца наблюдения:h0≏3·10−23.