291 research outputs found
The LISA Time-Delay Interferometry Zero-Signal Solution. I: Geometrical Properties
Time-Delay Interferometry (TDI) is the data processing technique needed for
generating interferometric combinations of data measured by the multiple
Doppler readouts available onboard the three LISA spacecraft. Within the space
of all possible interferometric combinations TDI can generate, we have derived
a specific combination that has zero-response to the gravitational wave signal,
and called it the {\it Zero-Signal Solution} (ZSS). This is a two-parameter
family of linear combinations of the generators of the TDI space, and its
response to a gravitational wave becomes null when these two parameters
coincide with the values of the angles of the source location in the sky.
Remarkably, the ZSS does not rely on any assumptions about the gravitational
waveform, and in fact it works for waveforms of any kind. Our approach is
analogous to the data analysis method introduced by G\"ursel & Tinto in the
context of networks of Earth-based, wide-band, interferometric gravitational
wave detectors observing in coincidence a gravitational wave burst. The ZSS
should be regarded as an application of the G\"ursel & Tinto method to the LISA
data.Comment: 29 pages, 17 Figure
Can gravitational waves be detected in quasar microlensing?
Studies of the lensed quasar have shown evidence
for microlensing in the brightness history of the quasar images. It had been
suggested that a frequency offset between the brightness fluctuations in each
of the two images might possibly be caused by gravitational radiation generated
by a massive black hole binary at the center of the lensing galaxy. This paper
demonstrates that the fluctuations produced by such a source of gravitational
waves will be too small to account for the observed frequency offsets.Comment: 10 pages, 1 fig; submitted to Ap
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