UNIDEF   23986
UNIDAD DE INVESTIGACION Y DESARROLLO ESTRATEGICO PARA LA DEFENSA
Unidad Ejecutora - UE
artículos
Título:
First low frequency all-sky search for continuous gravitational wave signals
Autor/es:
E. DOMINGUEZ ET AL
Revista:
PHYSICAL REVIEW D - PARTICLE AND FILDS
Editorial:
American Physical Society
Referencias:
Año: 2016
ISSN:
0556-2821
Resumen:
In this paper we present the results of the first low frequency all-sky search of continuous gravi-tational wave signals conducted on Virgo VSR2 and VSR4 data. The search covered the full sky, afrequency range between 20 Hz and 128 Hz with a range of spin-down between −1.0 × 10−10 Hz/sand +1.5 × 10−11 Hz/s, and was based on a hierarchical approach. The starting point was a setof short Fast Fourier Transforms (FFT), of length 8192 seconds, built from the calibrated straindata. Aggressive data cleaning, both in the time and frequency domains, has been done in order toremove, as much as possible, the effect of disturbances of instrumental origin. On each dataset anumber of candidates has been selected, using the FrequencyHough transform in an incoherent step.Only coincident candidates among VSR2 and VSR4 have been examined in order to strongly reducethe false alarm probability, and the most significant candidates have been selected. The criteria wehave used for candidate selection and for the coincidence step greatly reduce the harmful effect oflarge instrumental artifacts. Selected candidates have been subject to a follow-up by constructing anew set of longer FFTs followed by a further incoherent analysis, still based on the FrequencyHoughtransform. No evidence for continuous gravitational wave signals was found, therefore we have set apopulation-based joint VSR2-VSR4 90% confidence level upper limit on the dimensionless gravita-tional wave strain in the frequency range between 20 Hz and 128 Hz. This is the first all-sky searchfor continuous gravitational waves conducted at frequencies below 50 Hz. We set upper limits inthe range between about 10−24 and 2×10−23 at most frequencies. Our upper limits on signal strainshow an improvement of up to a factor of 2 with respect to the results of previous all-sky searchesat frequencies below 80 Hz.