2020ApJ...888L...8N -
Astrophys. J., 888, L8-L8 (2020/January-1)
A hidden friend for the Galactic Center black hole, Sgr A*.
NAOZ S., WILL C.M., RAMIREZ-RUIZ E., HEES A., GHEZ A.M. and DO T.
Abstract (from CDS):
The hierarchical nature of galaxy formation suggests that a supermassive black hole binary could exist in our galactic center. We propose a new approach to constraining the possible orbital configuration of such a binary companion to the galactic center black hole Sagittarius A* (Sgr A*) through the measurement of stellar orbits. Focusing on the star S0-2, we show that requiring its orbital stability in the presence of a companion to Sgr A* yields stringent constraints on the possible configurations of such a companion. Furthermore, we show that precise measurements of time variations in the orbital parameters of S0-2 could yield stronger constraints. Using existing data on S0-2 we derive upper limits on the binary black hole separation as a function of the companion mass. For the case of a circular orbit, we can rule out a 105 M☉ companion with a semimajor axis greater than 170 au or 0.8 mpc. This is already more stringent than bounds obtained from studies of the proper motion of Sgr A*. Including other stars orbiting the galactic center should yield stronger constraints that could help uncover the presence of a companion to Sgr A*. We show that a companion can also affect the accretion process, resulting in a variability that may be consistent with the measured infrared flaring timescales and amplitudes. Finally, if such a companion exists, it will emit gravitational wave radiation, potentially detectable with the Laser Interferometer Space Antenna (LISA).
Abstract Copyright:
© 2019. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Supermassive black holes - Astrophysical black holes - Galactic center - the Milky Way physics - Gravitation - Gravitational waves - Gravitational wave sources - the Milky Way - Milky Way dynamics
Simbad objects:
4
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2020ApJ...888L...8N and select 'bookmark this link' or equivalent in the popup menu