Standard-siren Hubble: H_0 = c z/d_L (low-z limit); luminosity distance via metric

Standard-siren Hubble-constant framework (Schutz 1986 Nature 323, 310). Setup: GW inspirals are 'self-calibrating' distance probes - the GW-amplitude h ~ (G M_chirp/c^2)^{5/3} (pi f_GW)^{2/3}/(c d_L) directly determines the luminosity…