Probing the nature of black holes: Deep in the mHz gravitational-wave sky

Baibhav, Vishal; Barack, Leor; Berti, Emanuele; Bonga, Béatrice; Brito, Richard (Richard Pires Brito); Vitor Cardoso; Compère, Geoffrey; Das, Saurya; Doneva, Daniela; Garcia-Bellido, Juan; Heisenberg, Lavinia; Hughes, Scott A.; Isi, Maximiliano; Jani, Karan; Kavanagh, Chris; Lukes-Gerakopoulos, Georgios; Mueller, Guido; Pani, Paolo; Petiteau, Antoine; Rajendran, Surjeet; Sotiriou, Thomas P.; Stergioulas, Nikolaos; Taylor, Alasdair; Vagenas, Elias; van de Meent, Maarten; Warburton, Niels; Wardell, Barry; Witzany, Vojtěch; Zimmerman, Aaron