Exploring the Mass Segregation Effect of X-Ray Sources in Globular Clusters. IV. Evidence of Black Hole Burning in ω Centauri
Abstract
Using X-ray sources as sensitive probes of stellar dynamical interactions in globular clusters (GCs), we study the mass segregation and binary burning processes in ω Cen. We show that the mass segregation of X-ray sources is quenched in ω Cen, while the X-ray source abundance of ω Cen is much smaller than other GCs, and the binary hardness ratio (defined as ${L}_{{\rm{X}}}/({L}_{K}{f}_{b})$ , with fb being the binary fraction, ${L}_{{\rm{X}}}$ and LK being the cumulative X-ray and K-band luminosity of GCs, respectively) of ω Cen is located far below the ${L}_{{\rm{X}}}/({L}_{K}{f}_{b})\mbox{--}{\sigma }_{c}$ correlation line of the dynamically normal GCs. This evidence suggests that the binary burning processes are highly suppressed in ω Cen, and other heating mechanisms, very likely a black hole subsystem (BHS), are essential in the dynamical evolution of ω Cen. Through the black hole burning processes (i.e., dynamical hardening of the BH binaries), the BHS is dominating the energy production of ω Cen, which also makes ω Cen a promising factory of gravitational-wave sources in the Galaxy.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2020
- DOI:
- 10.3847/1538-4357/abbdfc
- arXiv:
- arXiv:2010.00908
- Bibcode:
- 2020ApJ...904..198C
- Keywords:
-
- Globular star clusters;
- Binary stars;
- X-ray binary stars;
- Stellar mass black holes;
- Gravitational wave sources;
- Stellar dynamics;
- Intermediate-mass black holes;
- 656;
- 154;
- 1811;
- 1611;
- 677;
- 1596;
- 816;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 13 pages, 3 figures, 1 table. Accepted for publication in ApJ