We describe a directed search for continuous gravitational waves in data from the sixth initial LIGO science run. The target was the nearby globular cluster NGC 6544 at a distance of ≈2.7 kpc. The search covered a broad band of frequencies along with first and second frequency derivatives for a fixed sky position. The search coherently integrated data from the two LIGO interferometers over a time span of 9.2 days using the matched-filtering F-statistic. We found no gravitational-wave signals and set 95% confidence upper limits as stringent as 6.0×10−25 on intrinsic strain and 8.5×10−6 on fiducial ellipticity. These values beat the indirect limits from energy conservation for stars with characteristic spin-down ages older than 300 years and are within the range of theoretical predictions for possible neutron-star ellipticities. An important feature of this search was use of a barycentric resampling algorithm which substantially reduced computational cost; this method is used extensively in searches of Advanced LIGO and Virgo detector data.
Search for continuous gravitational waves from neutron stars in globular cluster NGC 6544
ALLOCCA, ANNALISA;BASTI, ANDREA;BOSCHI, VALERIO;CERRETANI, GIOVANNI;DEL POZZO, WALTER;DI LIETO, ALBERTO;FERRANTE, ISIDORO;FIDECARO, FRANCESCO;GONZALEZ CASTRO, JOSE MARIA;PASSAQUIETI, ROBERTO;PATRICELLI, BARBARA;POGGIANI, ROSA;RAZZANO, MASSIMILIANO;TONELLI, MAURO;
2017-01-01
Abstract
We describe a directed search for continuous gravitational waves in data from the sixth initial LIGO science run. The target was the nearby globular cluster NGC 6544 at a distance of ≈2.7 kpc. The search covered a broad band of frequencies along with first and second frequency derivatives for a fixed sky position. The search coherently integrated data from the two LIGO interferometers over a time span of 9.2 days using the matched-filtering F-statistic. We found no gravitational-wave signals and set 95% confidence upper limits as stringent as 6.0×10−25 on intrinsic strain and 8.5×10−6 on fiducial ellipticity. These values beat the indirect limits from energy conservation for stars with characteristic spin-down ages older than 300 years and are within the range of theoretical predictions for possible neutron-star ellipticities. An important feature of this search was use of a barycentric resampling algorithm which substantially reduced computational cost; this method is used extensively in searches of Advanced LIGO and Virgo detector data.File | Dimensione | Formato | |
---|---|---|---|
PhysRevD.95.082005.pdf
accesso aperto
Tipologia:
Versione finale editoriale
Licenza:
Tutti i diritti riservati (All rights reserved)
Dimensione
492.04 kB
Formato
Adobe PDF
|
492.04 kB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.