LISA sensitivity curve (Amaro-Seoane et al. 2017) and various gravitational wave frequencies from circular orbits around Sgr A*. The wave frequencies shown above are all for the dominant m = 2 mode, except for the dot-dashed and dotted vertical red lines, which correspond to the m = 3 and m = 4 harmonics of the ISCO of an extreme Kerr BH (a = M). The shaded pink area indicates the location of the frequencies from the ISCO when a ranges from zero to M. The Roche limits are those discussed in Sect. 5.1.