[eng] The interest in gravitational waves has greatly increased since the first detection in
2015 [1]. This has given extra momentum to the development of new detectors, which
will extend the accessible frequency range, while also improving the sensitivity compared to current detectors. Two of these detectors are studied here and they are the
Einstein Telescope (ET) and the Laser Interferometer Space Antenna (LISA). The ET
will probe the same frequency range as current detectors, though the band will be
widened (to about 1 to 104 Hz) and the sensitivity will be much better. LISA will
be an observatory in space and it will look for sources in an entirely new frequency
range at about 10−4
to 1 Hz. A wide variety of sources is expected to be found by
these detectors. Furthermore, they will have a much higher signal-to-noise ratio, which
means that they can find out more information about the sources.
These new detectors will have sensitivity curves that are different from current detectors such as the Laser Interferometer Gravitational-Wave Observatory (LIGO), which
means that their response to gravitational waves will be different. Some approximations were used for the LISA sensitivity curve and the consequence is that only the
lower part of the LISA frequency range was considered in this work. A comparison
was made between LISA, the ET and LIGO and it was found that LISA puts more
emphasis on the merger, whereas the ET emphasizes the inspiral instead.
These different sensitivity curves could mean that the performance of waveform models
is different. There are various methods for modelling gravitational waves from binary
black holes. The three main families of waveform models that are used in parameter estimation (which means that they need to have a low computational cost) are
compared. These are the phenomenological models IMRPhenomXHM [53] and IMRPhenomHM [52], the effective one-body reduced order model SEOBNRv4HM ROM
[54] and the hybrid surrogate model NRHybSur3dq8 [55]. All of these models use
higher modes of the multipole expansion and are non-precessing.
The highest similarities were found between IMRPhenomXHM and NRHybSur3dq8.
The overall performance for LIGO and the ET was similar, whereas the results for
LISA were not as good. This depends on the choice of how to scale the mass between
LIGO and LISA. The other results suggest that the matches for LISA might be better
when the full response can be used to include higher frequencies. For both LISA and
the ET it is found that the current models would induce systematic errors in parameter
estimation.