Detectability of Gravitational Waves from SN1987A

摘要

There is some observational evidence of the presence of a pulsating light source in the remnant of the supernova (SN)1987A [ 1 j. This source is considered to be a rotating neutron star. Fourier analysis of the light intensity of this source reveals a main narrow frequency peak and sidebands that are understood as a modulation of the main sinusoidal signal. A particular model of the neutron star invokes a precessing object to explain the modulation. From the Fourier spectrum of the source and changes in the frequency value, we can determine important parameters of the spinning neutron star as rotation frequency, precession frequency and spin down rate. The neutron star is believed to spin down due to the emission of gravitational waves. We give a precise calculation of the strain value of the gravitational waves reaching earth. We also discuss the relevant parameters that determine the strain. Our conclusion is that the existing bars and the first generation large scale interferometers as LIGO I will not be sensitive enough. Instead just a few days of integration time will be sufficient to detect the signal for the next generation detectors as LIGO II. If the interpretation of the observational data as the modulation of a precessing pulsar is correct our analysis points to SN 1987A as one of the few reliable sources of gravity waves for earth based gravitational waves detectors.