UTAPwiki/セミナー/宇宙物理学セミナー

Toshinori Hayashi

Title:
A strategy to search for an inner binary black hole from the motion of tertiary star

Abstract:
LIGO's detections of gravitational wave from binary black hole (BBH) merger events
give us an important open question for the origin and evolution of them.
Current proposed scenarios require long-term orbital evolutions before coalescence.
This fact implies the presence of many wide-separation BBHs as progenitors of merger events.
Currently, there are many proposals to search for star-black hole binaries with Gaia and TESS. It is expected that many such binaries are discovered in near future and some of them may be triples consisting of inner BBHs and tertiary stars.
Thus, we propose a methodology to search for such BBHs through radial velocity (RV) modulations of stars.We first consider a coplanar and near-circular triple and apply perturbation theory to obtain approximate RV formula and understand its nature.
Incidentally, we consider a degeneracy between a S-type circumbinary planet and inner unseen binary and investigate the correspondence of their parameters.
We also consider effects of eccentricities and inclinations on RV signals and discuss their importance to estimate orbital parameters.
Finally we present a preliminary progress of an on-going research on observational feasibility under RV errors considering Gaia and TESS fiducial binaries.


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Last-modified: 2019-06-27 (木) 17:39:16 (143d)