Response of the interferometric antenna to gravitational radiation from pulsars

Abstract

We present here a full calculation of the response of a laser interferometric gravitational wave detector on which gravitational radiation from a continuous source is incident. The observation time is taken to be of the order of few months. The long observation time implies that the motion of the detector is important and must be included in the response as a modulation effect. For simplicity we consider only two motions of the Earth , namely the rotation of the Earth about axis and the orbital motions about the sun. The orbit is assumed to be circular. We consider the detector to be situated and oriented arbitrarily on the Earth, except that we assume the arms of the detector must lie in the tangent plane to the Earth at the point where the detector is situated. The gravitational wave incident on the detector is assumed to be a plane wave having arbitrary direction and polarization. We also present here the computation of the quadrupole wave form of a typical continuous source – a pulsar-which is modelled as an almost spherical object of uniform density, spinning about an arbitrary axis with uniform angular velocity. We use techniques of spherical tensors and Gel’fandfunction developed in the literature to compute the waveform