List of Figures
Figure 1:
TimeDelay Interferometry (TDI). LISAlike detectors measure GWs by transmitting laser light between three spacecraft in triangular configuration, and comparing the optical phase of the incident lasers against reference lasers on each spacecraft. To avoid extreme requirements on laserfrequency stability over the course of the many seconds required for transmission around the triangle, data analysts will generate timedelayed linear combinations of the phase comparisons; the combinations simulate nearly equaldelay optical paths around the sides of the triangle, and (much like an equalarm Michelson interferometer) they suppress laser frequency noise. Many such combinations, including those depicted here, are possible, but altogether they comprise at most three independent gravitationalwave observables. Image reproduced by permission from [447], copyright by APS. 

Figure 2:
The discovery space for spacebased GW detectors, covering the lowfrequency region of the GW spectrum, . The discovery space is delineated by the LISA threshold sensitivity curve [277] in black, and by the eLISA sensitivity curve in red [21] (the curves were produced using the online sensitivity curve and source plotting website [321]). This region is populated by a wealth of strong sources, often in large numbers, including mergers of MBHs, EMRIs of stellarscale compact objects into MBHs, and millions of closeorbiting binary systems in the galaxy. Thousands of the strongest signals from these galactic binary systems should be individually resolvable, while the combined signals of millions of them produce a stochastic background at low frequencies. These systems provide ample opportunities for astrophysical tests of GR for gravitationalfield strengths that are not well characterized and studied in conventional astronomy. 

Figure 3:
Contours of constant SNR for MBH binaries observed with eLISA. The lefthand panel shows contours in the totalmass–redshift plane for equalmass binaries, while the righthand panel shows contours in the totalmass–massratio plane for sources at redshift . Image reproduced by permission from [21]. 

Figure 4:
Effect of the six possible GW polarization modes on a ring of test particles. The GW propagates in the zdirection for the upper three transverse modes, and in the xdirection for the lower three longitudinal modes. Only modes (a) and (b) are possible in GR. Image reproduced by permission from [471]. 

Figure 5:
Estimating all the binaryinspiral phasing coefficients of Eq. (51) yields differently shaped regions in the – plane, which must intersect near true mass values if GR is correct. Image reproduced by permission from [27], copyright by APS. 

Figure 6:
Constraints on phasing corrections in the ppE framework, as determined from LISA observations of massive–blackhole inspirals at and . The figure also includes the bounds derived from pulsar PSR J0737–3039 [492], the solarsystem bound on the graviton mass [435], and PNcoefficient bounds derived as described Section 5.2.1. The spike at corresponds to the degeneracy between the ppE correction and the initial GWphase parameter. (Adapted from [134].) 

Figure 7:
Poincaré map for a regular orbit (left panel) and a chaotic orbit (right panel) in the Manko–Novikov spacetime. Image reproduced by permission from [195], copyright by APS. 

Figure 8:
Comparative SNRs, as a function of redshifted blackhole mass , for the last year of inspiral of an equalmass MBH binary and for the ringdown after the merger of the system. The method used to generate this figure follows that of [182], updated to use a modern LISA sensitivity curve [277] with a lowfrequency cutoff of . The redshift is set to , at which the luminosity distance is using WMAP 7year parameters [271]. 