# Stellar binary black holes in the LISA band: a new class of standard sirens

## TL;DR

This paper proposes using stellar binary black holes detected by LISA as standard sirens to measure the Hubble constant with high precision, leveraging their luminosity distances and host galaxy redshifts.

## Contribution

It introduces a novel method to determine the Hubble constant using LISA-detected black hole binaries as standard sirens, enhancing local cosmological measurements.

## Key findings

- Hubble constant can be measured at 5% accuracy with two million km arm-length.
- Hubble constant can be measured at 2% accuracy with five million km arm-length.
- Effective for a population consistent with current LIGO rates.

## Abstract

The recent Advanced LIGO detections of coalescing black hole binaries (BHBs) imply a large population of such systems emitting at milli-Hz frequencies, accessible to the Laser Interferometer Space Antenna (LISA). We show that these systems provide a new class of cosmological standard sirens. Direct LISA luminosity distance -$D_l$- measurements, combined with the inhomogeneous redshift -$z$- distribution of possible host galaxies provide an effective way to populate the $D_l-z$ diagram at $z<0.1$, thus allowing a precise local measurement of the Hubble expansion rate. To be effective, the method requires a sufficiently precise LISA distance determination and sky localization of a sizeable number of BHBs, which is best achieved for a 6-link detector configuration. We find that, for a BHB population consistent with current fiducial LIGO rates, the Hubble constant $H_0$ can be determined at the $\sim$5% and $\sim$2% level (68% confidence) assuming two and five million Km arm-length respectively.