Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2010-11-17
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
10 pages, 5 figures
Scientific paper
In recent numerical simulations \citep{matsubayashi07,lockmann08}, it has been found that the eccentricity of supermassive black hole(SMBH) - intermediate black hole(IMBH) binaries grows toward unity through interactions with stellar background. This increase of eccentricity reduces the merging timescale of the binary through the gravitational radiation to the value well below the Hubble Time. It also gives the theoretical explanation of the existence of eccentric binary such as that in OJ287 \citep{lehto96, valtonen08}. In self-consistent N-body simulations, this increase of eccentricity is always observed. On the other hand, the result of scattering experiment between SMBH binaries and field stars \citep{quinlan96} indicated no increase of eccentricity. This discrepancy leaves the high eccentricity of the SMBH binaries in $N$-body simulations unexplained. Here we present a stellar-dynamical mechanism that drives the increase of the eccentricity of an SMBH binary with large mass ratio. There are two key processes involved. The first one is the Kozai mechanism under non-axisymmetric potential, which effectively randomizes the angular momenta of surrounding stars. The other is the selective ejection of stars with prograde orbits. Through these two mechanisms, field stars extract the orbital angular momentum of the SMBH binary. Our proposed mechanism causes the increase in the eccentricity of most of SMBH binaries, resulting in the rapid merger through gravitational wave radiation. Our result has given a definite solution to the "last-parsec problem".
An Sangyong
Funato Yoko
Iwasawa Masaki
Makino Junichiro
Matsubayashi Tatsushi
No associations
LandOfFree
Eccentric evolution of SMBH binaries does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Eccentric evolution of SMBH binaries, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Eccentric evolution of SMBH binaries will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-112958