The missing link in gravitational-wave astronomy: A summary of discoveries waiting in the decihertz range

Manuel Arca Sedda; Christopher P L Berry; Karan Jani; Pau Amaro-Seoane; Pierre Auclair; Jonathon Baird; Tessa Baker; Emanuele Berti; Katelyn Breivik; Chiara Caprini; Xian Chen; Daniela Doneva; Jose M Ezquiaga; K E Saavik Ford; Michael L Katz; Shimon Kolkowitz; Barry McKernan; Guido Mueller; Germano Nardini; Igor Pikovski; Surjeet Rajendran; Alberto Sesana; Lijing Shao; Nicola Tamanini; Niels Warburton; Helvi Witek; Kaze Wong; Michael Zevin

doi:10.1007/s10686-021-09713-z

The missing link in gravitational-wave astronomy: A summary of discoveries waiting in the decihertz range

Exp Astron (Dordr). 2021;51(3):1427-1440. doi: 10.1007/s10686-021-09713-z. Epub 2021 Apr 29.

Authors

Manuel Arca Sedda¹, Christopher P L Berry^{2

3}, Karan Jani⁴, Pau Amaro-Seoane^{5

6

7

8}, Pierre Auclair⁹, Jonathon Baird¹⁰, Tessa Baker¹¹, Emanuele Berti¹², Katelyn Breivik¹³, Chiara Caprini⁹, Xian Chen^{6

14}, Daniela Doneva¹⁵, Jose M Ezquiaga¹⁶, K E Saavik Ford^{17

18}, Michael L Katz², Shimon Kolkowitz¹⁹, Barry McKernan^{17

18}, Guido Mueller²⁰, Germano Nardini²¹, Igor Pikovski^{22

23}, Surjeet Rajendran¹², Alberto Sesana²⁴, Lijing Shao^{6

25}, Nicola Tamanini²⁶, Niels Warburton²⁷, Helvi Witek²⁸, Kaze Wong¹², Michael Zevin²

Affiliations

¹ Astronomisches Rechen-Institut, Zentrüm für Astronomie, Universität Heidelberg, Mönchofstr. 12-14, Heidelberg, Germany.
² Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 USA.
³ SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK.
⁴ Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212 USA.
⁵ Universitat Politècnica de València, IGIC, Valencia, Spain.
⁶ Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing, 100871 China.
⁷ Institute of Applied Mathematics, Academy of Mathematics and Systems Science, CAS, Beijing, 100190 China.
⁸ Zentrum für Astronomie und Astrophysik, TU Berlin, Hardenbergstraße 36, 10623 Berlin, Germany.
⁹ Laboratoire Astroparticule et Cosmologie, CNRS UMR 7164, Université Paris-Diderot, 10 rue Alice Domon et Léonie Duquet, 75013 Paris, France.
¹⁰ High Energy Physics Group, Physics Department, Imperial College London, Blackett Laboratory, Prince Consort Road, London, SW7 2BW UK.
¹¹ School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS UK.
¹² Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 USA.
¹³ Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7 Canada.
¹⁴ Astronomy Department, School of Physics, Peking University, Beijing, 100871 China.
¹⁵ Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen, 72076 Germany.
¹⁶ Kavli Institute for Cosmological Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 USA.
¹⁷ City University of New York-BMCC, Chambers St, New York, NY 10007 USA.
¹⁸ Department of Astrophysics, American Museum of Natural History, New York, NY 10028 USA.
¹⁹ Department of Physics, University of Wisconsin - Madison, Madison, WI 53706 USA.
²⁰ Department of Physics, University of Florida, PO Box 118440, Gainesville, Florida 32611 USA.
²¹ Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway.
²² Department of Physics, Stevens Institute of Technology, Hoboken, NJ 07030 USA.
²³ Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden.
²⁴ Università di Milano Bicocca, Dipartimento di Fisica G. Occhialini, Piazza della Scienza 3, I-20126 Milano, Italy.
²⁵ National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 China.
²⁶ Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
²⁷ School of Mathematics and Statistics, University College Dublin, Belfield, Dublin 4 Ireland.
²⁸ Department of Physics, King's College London, Strand, London WC2R 2LS UK.

Abstract

Since 2015 the gravitational-wave observations of LIGO and Virgo have transformed our understanding of compact-object binaries. In the years to come, ground-based gravitational-wave observatories such as LIGO, Virgo, and their successors will increase in sensitivity, discovering thousands of stellar-mass binaries. In the 2030s, the space-based LISA will provide gravitational-wave observations of massive black holes binaries. Between the $\sim 10$ -10³ Hz band of ground-based observatories and the $\sim 1 0^{- 4}$ -10^{- 1} Hz band of LISA lies the uncharted decihertz gravitational-wave band. We propose a Decihertz Observatory to study this frequency range, and to complement observations made by other detectors. Decihertz observatories are well suited to observation of intermediate-mass ( $\sim 1 0^{2}$ -10⁴ M _⊙) black holes; they will be able to detect stellar-mass binaries days to years before they merge, providing early warning of nearby binary neutron star mergers and measurements of the eccentricity of binary black holes, and they will enable new tests of general relativity and the Standard Model of particle physics. Here we summarise how a Decihertz Observatory could provide unique insights into how black holes form and evolve across cosmic time, improve prospects for both multimessenger astronomy and multiband gravitational-wave astronomy, and enable new probes of gravity, particle physics and cosmology.

Keywords: Binary evolution; Black holes; Decihertz observatories; Gravitational waves; Intermediate-mass black holes; Multiband gravitational-wave astronomy; Multimessenger astronomy; Neutron stars; Space-based detectors; Stochastic backgrounds; Tests of general relativity; Voyage 2050; White dwarfs.