Black hole spin–orbit misalignment in the x-ray binary MAXI J1820+070

Science, vol. 375, pp. 874–876

Abstract

The observational signatures of black holes in x-ray binary systems depend on their masses, spins, accretion rate, and the misalignment angle between the black hole spin and the orbital angular momentum. We present optical polarimetric observations of the black hole x-ray binary MAXI J1820+070, from which we constrain the position angle of the binary orbital. Combining this with previous determinations of the relativistic jet orientation, which traces the black hole spin, and the inclination of the orbit, we determine a lower limit of 40° on the spin-orbit misalignment angle. The misalignment must originate from either the binary evolution or black hole formation stages. If other x-ray binaries have similarly large misalignments, these would bias measurements of black hole masses and spins from x-ray observations.

Authors 13

1. Juri Poutanen corresponding

   Nordic Institute for Theoretical Physics · University of Turku · Stockholm University · Space Research Institute · KTH Royal Institute of Technology

   Affiliation as printed

   Department of Physics and Astronomy, FI-20014 University of Turku, Finland

   Nordic Institute for Theoretical Physics (Nordita), KTH Royal Institute of Technology and Stockholm University, SE-10691 Stockholm, Sweden

   Space Research Institute (IKI) of the Russian Academy of Sciences, 117997 Moscow, Russia

2. Alexandra Veledina

   Nordic Institute for Theoretical Physics · University of Turku · Stockholm University · Space Research Institute · KTH Royal Institute of Technology

   Affiliation as printed

   Department of Physics and Astronomy, FI-20014 University of Turku, Finland

   Nordic Institute for Theoretical Physics (Nordita), KTH Royal Institute of Technology and Stockholm University, SE-10691 Stockholm, Sweden

   Space Research Institute (IKI) of the Russian Academy of Sciences, 117997 Moscow, Russia

3. Andrei V. Berdyugin

   University of Turku

   Affiliation as printed

   Department of Physics and Astronomy, FI-20014 University of Turku, Finland

4. S. V. Berdyugina

   Institut für Sonnenphysik

   Affiliation as printed

   Leibniz-Institut für Sonnenphysik, 79104 Freiburg, Germany

5. Helen E. Jermak

   Liverpool John Moores University

   Affiliation as printed

   Astrophysics Research Institute, Liverpool John Moores University, L3 5RF Liverpool, UK

6. Peter Gustaaf Jonker Aachen Space Research Organisation of the Netherlands Netherlands Institute for Space Research

   Radboud University Nijmegen · Space Research Organisation Netherlands

   Affiliation as printed

   Department of Astrophysics, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University, NL-6500 GL Nijmegen, Netherlands

   Space Research Organisation of the Netherlands (SRON), Netherlands Institute for Space Research, NL-2333, CA Leiden, Netherlands

7. Jari J. E. Kajava

   University of Turku · Centro de Astrobiología

   Affiliation as printed

   Centro de Astrobiología, Villanueva de la Cañada, S-28692 Madrid, Spain

   Department of Physics and Astronomy, FI-20014 University of Turku, Finland

8. Ilia A. Kosenkov

   University of Turku

   Affiliation as printed

   Department of Physics and Astronomy, FI-20014 University of Turku, Finland

9. Vadim Kravtsov

   University of Turku

   Affiliation as printed

   Department of Physics and Astronomy, FI-20014 University of Turku, Finland

10. V. Piirola

    University of Turku

    Affiliation as printed

    Department of Physics and Astronomy, FI-20014 University of Turku, Finland

11. Manisha Shrestha

    University of Denver · Liverpool John Moores University

    Affiliation as printed

    Astrophysics Research Institute, Liverpool John Moores University, L3 5RF Liverpool, UK

    Department of Physics and Astronomy, University of Denver, Denver, CO 80208, USA

12. Manuel A. P. Torres

    Universidad de La Laguna · Instituto de Astrofísica de Canarias

    Affiliation as printed

    Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain

    Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife, Spain

13. Sergey S. Tsygankov

    University of Turku · Space Research Institute

    Affiliation as printed

    Department of Physics and Astronomy, FI-20014 University of Turku, Finland

    Space Research Institute (IKI) of the Russian Academy of Sciences, 117997 Moscow, Russia