Continuous signals are emitted by various
astrophysical sources (rotating neutron star, neutron star in a
binary system).
They carry important information on their sources and on
fundamental physics.
The signals are very weak but, due to the fact they are continuos,
it is possible to implement search procedures that build up the SNR
with the time.
The sensitivity of the detectors
to continuous signals is a function of
the noise spectral amplitude (1/sqrt(Hz)) and
of the observation time.
Read this
note for an introduction to the analysis of continuous waves
with resonant detectors.
We have developed a
procedure for the search of signals from periodic sources in the
data of gravitational wave detectors and we have used it to analyze
one year of data from the resonant detector Explorer, searching for
sources located in the Galactic Center (GC).
No signals with amplitude greater than
2.9*10 -24 ,
in the range 921.32-921.38 Hz, were observed using data collected
over a time period of 95.7 days,
(for a source located at rigth ascension=17.70 +- 0.01 hours
and declination=-29.00 +- 0.05 degrees).
The procedure and the results have been published
on PRD 65,022201 (2002):
click here for
the PDF file
We are now running, in collaboration with A. Krolak, K. Borkovsky
and P. Jaranovsky (Poland),
an All-Sky search using two days of the
Explorer 1991 data.
The procedure is described here (PDF file) and has been published
on PRD 65,042003 (2002)
The web site for the ALL-SKY search is
HERE !