English

Massive binaries in the vicinity of Sgr A*

Astrophysics of Galaxies 2015-06-16 v1

Abstract

A long-term spectroscopic and photometric survey of the most luminous and massive stars in the vicinity of the super-massive black hole Sgr A* revealed two new binaries; a long-period Ofpe/WN9 binary, GCIRS 16NE, with a modest eccentricity of 0.3 and a period of 224 days and an eclipsing Wolf-Rayet binary with a period of 2.3 days. Together with the already identified binary GCIRS 16SW, there are now three confirmed OB/WR binaries in the inner 0.2\,pc of the Galactic Center. Using radial velocity change upper limits, we were able to constrain the spectroscopic binary fraction in the Galactic Center to FSB=0.270.19+0.29F_{\rm SB}=0.27^{+0.29}_{-0.19} at a confidence level of 95%, a massive binary fraction similar to that observed in dense clusters. The fraction of eclipsing binaries with photometric amplitudes Δm>0.4\Delta m>0.4 is FEBGC=3±2F^{\rm GC}_{\rm EB}=3\pm2%, which is consistent with local OB star clusters (FEB=1F_{\rm EB}=1%). Overall the Galactic Center binary fraction seems to be close to the binary fraction in comparable young clusters.

Keywords

Cite

@article{arxiv.1307.7996,
  title  = {Massive binaries in the vicinity of Sgr A*},
  author = {O. Pfuhl and T. Alexander and S. Gillessen and F. Martins and R. Genzel and F. Eisenhauer and T. K. Fritz and T. Ott},
  journal= {arXiv preprint arXiv:1307.7996},
  year   = {2015}
}

Comments

5 figures, submitted to ApJ