Research Note

A note on gravitational wave lensing

¹ Dipartimento di Fisica, Università di Lecce, and INFN, Sezione di Lecce, via Arnesano, CP 193, 73100 Lecce, Italy
² Department of Mathematical Sciences, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
³ Department of Mathematics, Quaid-i-Azam University, Islamabad, Pakistan

Corresponding author: F. De Paolis, Francesco.DePaolis@le.infn.it

Received: 24 May 2002
Accepted: 22 August 2002

Abstract

In a recent paper (Ruffa [CITE]) it was proposed that the massive black hole at the Galactic center may act as a gravitational lens focusing gravitational wave energy to the Earth. Considering the gravitational wave signal emitted by galactic spinning pulsars, an enhancement in the gravitational wave intensity by a factor of a few thousand is found. For galactic and extra-galactic sources the intensity enhancement can be as high as 4000 and 17 000, respectively. In this note we consider the probability of significant signal enhancement from galactic and extra-galactic pulsars by the proposed mechanism and find that it is actually negligible. The lensing effect due to a possible companion object (a star or the galactic center black hole) of the gravitational wave source is also investigated in the framework of the classical microlensing theory.