FIRST SEARCH FOR GRAVITATIONAL WAVES FROM THE YOUNGEST KNOWN NEUTRON STAR

Abstract

We present a search for periodic gravitational waves from the neutron star in\nthe supernova remnant Cassiopeia A. The search coherently analyzes data in a\n12-day interval taken from the fifth science run of the Laser Interferometer\nGravitational-Wave Observatory. It searches gravitational wave frequencies from\n100 to 300 Hz, and covers a wide range of first and second frequency\nderivatives appropriate for the age of the remnant and for different spin-down\nmechanisms. No gravitational wave signal was detected. Within the range of\nsearch frequencies, we set 95% confidence upper limits of 0.7--1.2e-24 on the\nintrinsic gravitational wave strain, 0.4--4e-4 on the equatorial ellipticity of\nthe neutron star, and 0.005--0.14 on the amplitude of r-mode oscillations of\nthe neutron star. These direct upper limits beat indirect limits derived from\nenergy conservation and enter the range of theoretical predictions involving\ncrystalline exotic matter or runaway r-modes. This is the first gravitational\nwave search to present upper limits on r-modes.\n