Predicting gravitational wave signals from BPASS white dwarf binary and black hole binary populations of a Milky Way-like galaxy model for LISA

Monthly Notices of the Royal Astronomical Society, vol. 534, pp. 1707–1728

Abstract

ABSTRACT Galactic white dwarf binaries (WDBs) and black hole binaries (BHBs) will be gravitational wave (GW) sources for LISA. Their detection will provide insights into binary evolution and the evolution of our Galaxy through cosmic history. Here, we make predictions of the expected WDB and BHB population within our Galaxy. We combine predictions of the compact remnant binary populations expected by stellar evolution from the detailed Binary Population and Spectral Synthesis (BPASS) code, with a Milky Way analogue galaxy model from the Feedback in Realistic Environment (FIRE) simulations. We use PhenomA and legwork to simulate LISA observations. Both packages make similar predictions that on average four Galactic BHBs and 673 Galactic WDBs are above the signal-to-noise ratio (SNR) threshold of 7 after a four-year mission. We compare these predictions to earlier results using the binary star evolution (BSE) code with the same FIRE model galaxy. We find that BPASS predicts a few more LISA observable Galactic BHBs and a twentieth of the Galactic WDBs. The differences are due to the different physical assumptions that have gone into the binary evolution calculations. These results indicate that the expected population of compact binaries that LISA will detect depends very sensitively on the binary population synthesis models used and thus observations of the LISA population will provide tight constraints on our modelling of binary stars. Finally, from our synthetic populations, we have created mock LISA signals that can be used to test and refine data processing methods of the eventual LISA observations.

Authors 6

1. Petra N Tang corresponding

   University of Auckland

   Affiliation as printed

   Department of Physics, University of Auckland , Private Bag 92019, Auckland ,

2. J. J. Eldridge corresponding

   University of Auckland

   Affiliation as printed

   Department of Physics, University of Auckland , Private Bag 92019, Auckland ,

3. Renate Meyer corresponding

   University of Auckland

   Affiliation as printed

   Department of Statistics, University of Auckland , Private Bag 92019, Auckland ,

4. A. Lamberts

   Centre National de la Recherche Scientifique · Université Côte d'Azur · Lagrange Laboratory · Astrophysique Relativiste, Théories, Expériences, Métrologie, Instrumentation, Signaux · Observatoire de la Côte d’Azur

   Affiliation as printed

   Observatoire de la Côte d’Azur, Université Côte d’Azur, CNRS , Artemis, Bd de l’Observatoire, F-06304 Nice ,

   Observatoire de la Côte d’Azur, Université Côte d’Azur, CNRS, Laboratoire Lagrange , Bd de l’Observatoire, F-06304 Nice ,

5. Guillaume Boileau

   University of Antwerp

   Affiliation as printed

   Department of Physics, University of Antwerpen , Prinsstraat 13, 2000 Antwerpen ,

6. Wouter G. J. van Zeist Aachen Leiden Observatory

   Leiden University · Radboud University Nijmegen · University of Auckland · Leiden Observatory

   Affiliation as printed

   Department of Astrophysics/IMAPP, Radboud University , PO Box 9010, 6500 GL, Nijmegen ,

   Department of Physics, University of Auckland , Private Bag 92019, Auckland ,

   Leiden Observatory, Leiden University , PO Box 9513, 2300 RA, Leiden ,