Searching for Black Hole Candidates by LAMOST and ASAS-SN. (arXiv:1909.06392v1 [astro-ph.SR])

Searching for Black Hole Candidates by LAMOST and ASAS-SN. (arXiv:1909.06392v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_L/0/1/0/all/0/1">Ling-Lin Zheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gu_W/0/1/0/all/0/1">Wei-Min Gu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yi_T/0/1/0/all/0/1">Tuan Yi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fu_J/0/1/0/all/0/1">Jin-Bo Fu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mu_H/0/1/0/all/0/1">Hui-Jun Mu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_F/0/1/0/all/0/1">Fan Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_S/0/1/0/all/0/1">Song Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bai_Z/0/1/0/all/0/1">Zhong-Rui Bai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sou_H/0/1/0/all/0/1">Hao Sou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bai_Y/0/1/0/all/0/1">Yu Bai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dong_Y/0/1/0/all/0/1">Yi-Ze Dong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_H/0/1/0/all/0/1">Hao-Tong Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lei_Y/0/1/0/all/0/1">Ya-Juan Lei</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">Junfeng Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_J/0/1/0/all/0/1">Jianfeng Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_J/0/1/0/all/0/1">Jifeng Liu</a>

Most dynamically confirmed stellar-mass black holes and the candidates were
originally selected from X-ray outbursts. In the present work, we search for
black hole candidates in the LAMOST survey by using the spectra along with
photometry from the ASAS-SN survey, where the orbital period of the binary may
be revealed by the periodic light curve, such as the ellipsoidal modulation
type. Our sample consists of 9 binaries, where each source contains a giant
star with large radial velocity variation ($Delta V_{rm R} > 70~{rm
km~s^{-1}}$) and periods known from light curves. We focus on the 9 sources
with long periods ($T_{rm ph} > 5$ days) and evaluate the mass $M_2$ of the
optically invisible companion. Since the observed $Delta V_{rm R}$ from only
a few repeating spectroscopic observations is a lower limit of the real
amplitude, the real mass $M_2$ can be significantly higher than the current
evaluation. It is likely an efficient method to place constraints on $M_2$ by
combining $Delta V_{rm R}$ from LAMOST and $T_{rm ph}$ from ASAS-SN,
particularly by the ongoing LAMOST Medium Resolution Survey.

Most dynamically confirmed stellar-mass black holes and the candidates were
originally selected from X-ray outbursts. In the present work, we search for
black hole candidates in the LAMOST survey by using the spectra along with
photometry from the ASAS-SN survey, where the orbital period of the binary may
be revealed by the periodic light curve, such as the ellipsoidal modulation
type. Our sample consists of 9 binaries, where each source contains a giant
star with large radial velocity variation ($Delta V_{rm R} > 70~{rm
km~s^{-1}}$) and periods known from light curves. We focus on the 9 sources
with long periods ($T_{rm ph} > 5$ days) and evaluate the mass $M_2$ of the
optically invisible companion. Since the observed $Delta V_{rm R}$ from only
a few repeating spectroscopic observations is a lower limit of the real
amplitude, the real mass $M_2$ can be significantly higher than the current
evaluation. It is likely an efficient method to place constraints on $M_2$ by
combining $Delta V_{rm R}$ from LAMOST and $T_{rm ph}$ from ASAS-SN,
particularly by the ongoing LAMOST Medium Resolution Survey.

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