Upper limits on gravitational wave emission from 78 radio pulsars

Abstract

We present upper limits on the gravitational wave emission from 78 radio pulsars based on data from the third and fourth science runs of the LIGO and GEO 600 gravitational wave detectors. The data from both runs have been combined coherently to maximize sensitivity. For the first time, pulsars within binary (or multiple) systems have been included in the search by taking into account the signal modulation due to their orbits. Our upper limits are therefore the first measured for 56 of these pulsars. For the remaining 22, our results improve on previous upper limits by up to a factor of 10. For example, our tightest upper limit on the gravitational strain is 2:6 10 ÿ25 for PSR J1603 ÿ 7202, and the equatorial ellipticity of PSR J2124-3358 is less than 10 ÿ6 . Furthermore, our strain upper limit for the Crab pulsar is only 2.2 times greater than the fiducial spin-down limit.

Are Neutron Stars with Crystalline Color-Superconducting Cores Relevant for the LIGO Experiment?

“…(2). We compare these ellipticities to the best current upper limit set by LIGO using the S3/S4 science runs, which is ǫ = 7.1 × 10 −7 for PSR J2124-3358 [5]. It is quite clear that, if the maximum breaking strain applies and the star is maximally deformed, then LIGO would have made a detection.…”

“…A magnetic star in which the magnetic field is misaligned visa-vi the rotation axis may also be deformed in an interesting way [3,4]. Estimates of the possible level of neutron star asymmetry are of great current interest given the improving upper limits obtained by LIGO [5]. The best current limit set by the detectors corresponds to a deformation of ǫ < 7.1 × 10 −7 in PSR 2124-3358, a neutron star spinning at 202.8 Hz.…”

“…where ν is the neutron star spin frequency, I zz it's principal moment of inertia and r the distance from Earth [5]. In order to facilitate a direction comparison with the ellipticities discussed in [5], we fix I zz = 10 45 g cm 2 rather than calculating it for each of our stellar models.…”

Searches for Gravitational Waves from Binary Neutron Stars: A Review

“…There are four categories of gravitational wave signals which ground-based interferometers are currently trying to detect: quasi-periodic signals, such as those expected from pulsars [3,4,5,6,7], stochastic background signals, such as remnant gravitational waves from the Big Bang [8,9,10,11,12], unmodeled burst signals, such as those that might be emitted by supernovae [13,14,15,16,17,18,19], and inspiral signals, such as those from neutron star or black hole binaries [20,21,22,23,24,25,26]. In this article, we will only be concerned with the last of these searches, and in particular the search for neutron star binaries [20,23,25,26].…”

The path to the enhanced and advanced LIGO gravitational-wave detectors

“…A number of searches for gravitational waves from various sources have already been conducted with data from LIGO and its international partners, see e.g., [6,7,8,9,10,11]. Data from LIGO, GEO600 and Virgo from S5 (and Virgo's corresponding run, VSR1) is currently being analyzed jointly by the LIGO Scientific Collaboration (which includes the GEO Collaboration) and the Virgo Collaboration.…”