sidebar
Figure 2
Figure 2: The discovery space for space-based GW detectors, covering the low-frequency region of the GW spectrum, −5 10 Hz ≲ f ≲ 0.1 Hz. 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 stellar-scale compact objects into MBHs, and millions of close-orbiting 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 gravitational-field strengths that are not well characterized and studied in conventional astronomy.