The third generation of gravitational wave observatories and their science reach

Abstract

Large gravitational wave interferometric detectors, like Virgo and LIGO, demonstrated the capability to reach their design sensitivity, but to transform these machines into an effective observational instrument for gravitational wave astronomy a large improvement in sensitivity is required. Advanced detectors in the near future and third-generation observatories in more than one decade will open the possibility to perform gravitational wave astronomical observations from the Earth. An overview of the possible science reaches and the technological progress needed to realize a third-generation observatory are discussed in this paper. The status of the project Einstein Telescope (ET), a design study of a third-generation gravitational wave observatory, will be reported.

Accessibility of the gravitational-wave background due to binary coalescences to second and third generation gravitational-wave detectors

“…The third generation detectors (assuming ET-D strain sensitivity curve [11,12] for two collocated detectors and one year of exposure) are expected to be substantially more sensitive to the GWB due to binaries, reaching (and often surpassing) the pessimistic local merger rates of BNS (R local ∼ 0.01 Mpc −3 Myr −1 ), BBH (R local ∼ 10 −4 Mpc −3 Myr −1 ), and BHNS (R local ∼ 6 × 10 −4 Mpc −3 Myr −1 ) [53]. In fact, the binary coalescence GWB will be a foreground masking the GWB background due to early-universe sources (inflationary models [56,57], or phase transitions models [58]) which may be one of the targets of the third generation detectors.…”

“…For each plot we show the region in the λ − Mc parameter space excluded by the 95% confidence upper limit of LIGO [31]. We also show regions in the λ − Mc parameter space that will be probed by the Advanced LIGO collocated detector pair (assuming 1 year of exposure [5,6]), and by the Einstein Telescope (assuming two collocated detectors with ET-D sensitivity and one year of exposure [11,12]) at 2σ level (that is, assuming the signal-to-noise ratio of 2). These regions are to be compared with the expected local coalescence rates shown as horizontal dashed lines: top-to-bottom they correspond to maximal, optimistic, realistic, and pessimistic estimates presented in [53].…”

“…Furthermore, there are already efforts under way to design the third generation gravitational wave detectors, with another factor of 10 improvement in sensitivity. This includes the Einstein Telescope project [11,12], for which the design study was recently completed. These detectors are expected to open a new era in astronomy and astrophysics, providing new observations of various events and objects in the universe, complementary to the standard electromagnetic observations.…”

Gravity Talks: Observing the Universe with Gravitational Waves

“…The most complete study was for the European Einstein Telescope [5,6], which will probably bid for first funding toward the end of the current decade.…”

A thermal noise model for a branched system of harmonic oscillators

“…For this reason the use of low dissipative materials is a consolidated choice to improve the sensitivity of the enhanced and advanced interferometers [3,4,5]. Another challenging choice is to go at cryogenic temperatures pushing down to 1 Hz the sensitivity bandwidth of the third generation interferometers like ET [2]. The recent new calculation of the mirror thermal noise [1] for the Virgo-like detectors has shown that as soon as we are dealing with low losses mirror pendulum, the upper suspension losses starts to contribute via its recoil and must be included in the computation.…”