Narrow-band search of continuous gravitational-wave signals from Crab and Vela pulsars in Virgo VSR4 data
Abstract
In this paper we present the results of a coherent narrow-band search for continuous gravitational-wave signals from the Crab and Vela pulsars conducted on Virgo VSR4 data. In order to take into account a possible small mismatch between the gravitational-wave frequency and two times the star rotation frequency, inferred from measurement of the electromagnetic pulse rate, a range of 0.02 Hz around two times the star rotational frequency has been searched for both the pulsars. No evidence for a signal has been found and 95% confidence level upper limits have been computed assuming both that polarization parameters are completely unknown and that they are known with some uncertainty, as derived from x-ray observations of the pulsar wind torii. For Vela the upper limits are comparable to the spin-down limit, computed assuming that all the observed spin-down is due to the emission of gravitational waves. For Crab the upper limits are about a factor of 2 below the spin-down limit, and represent a significant improvement with respect to past analysis. This is the first time the spin-down limit is significantly overcome in a narrow-band search.
- Publication:
-
Physical Review D
- Pub Date:
- January 2015
- DOI:
- 10.1103/PhysRevD.91.022004
- arXiv:
- arXiv:1410.8310
- Bibcode:
- 2015PhRvD..91b2004A
- Keywords:
-
- 04.30.-w;
- 04.80.Nn;
- 95.75.Wx;
- 97.60.Gb;
- Gravitational waves: theory;
- Gravitational wave detectors and experiments;
- Time series analysis time variability;
- Pulsars;
- Astrophysics - Instrumentation and Methods for Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena;
- General Relativity and Quantum Cosmology
- E-Print:
- 17 pages, 11 figures