Detection of a 100,000 M ⊙ black hole in M31's Most Massive Globular Cluster: A Tidally Stripped Nucleus
Detection of a 100,000 M ⊙ black hole in M31's Most Massive Globular Cluster: A Tidally Stripped Nucleus
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在M31‘S最大质量球状星团中探测到一个100000 M⊙黑洞：一个潮汐剥离核
DOI：
10.3847/1538-4357/ac339f
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发表时间：
2021-11
期刊：
影响因子：
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通讯作者：
R. Pechetti;A. Seth;S. Kamann;N. Caldwell;J. Strader;M. den Brok;N. Luetzgendorf;N. Neumayer;K. Voggel
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文献类型：
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作者：
R. Pechetti;A. Seth;S. Kamann;N. Caldwell;J. Strader;M. den Brok;N. Luetzgendorf;N. Neumayer;K. Voggel
我们研究了M31中质量最大的球状星团B 023-G 078中中心黑洞的存在。我们提出了高分辨率，自适应光学辅助，积分场光谱运动学从双子座/NIFS，显示出强大的旋转（1020 km s-1）和速度色散上升向中心（37 km s-1）。我们结合联合收割机的运动学数据与质量模型的基础上的两个组件适合HST ACS/HRC数据的集群，以估计一个假定的BH的质量。我们的动力学模型表明，BH分量为9.1−2.8+2.6× 104 M <$（1σ不确定性）的>3σ检测。星团的恒星质量推断为6.22−0.05+0.03× 106 M <$，与先前的估计一致，因此BH占其质量的1.5%。我们研究所观察到的运动学是否是由恒星质量BH的集合所造成的建模作为一个普卢默配置文件的扩展暗质量。扩展质量的尺寸范围上限为0.56 pc（95%置信度），这并不排除扩展质量。有令人信服的证据表明，B 023-G 078是恒星质量>109 M的星系潮汐剥离核，包括其高质量，双分量光度剖面，颜色，金属丰度梯度和金属丰度分布。鉴于新出现的证据表明，大于109 M的星系的中央黑洞占有率很高，对运动学数据最合理的解释是B 023-G 078拥有一个中央黑洞。这使它成为在低质量（<107 M）剥离核中最强的BH探测，也是少数动态探测到的中等质量BH之一。
We investigate the presence of a central black hole (BH) in B023-G078, M31's most massive globular cluster. We present high-resolution, adaptive-optics assisted, integral-field spectroscopic kinematics from Gemini/NIFS that show a strong rotation (∼20 km s−1) and a velocity dispersion rise toward the center (37 km s−1). We combine the kinematic data with a mass model based on a two-component fit to HST ACS/HRC data of the cluster to estimate the mass of a putative BH. Our dynamical modeling suggests a >3σ detection of a BH component of 9.1−2.8+2.6×104M⊙ (1σ uncertainties). The inferred stellar mass of the cluster is 6.22−0.05+0.03×106M⊙ , consistent with previous estimates, thus the BH makes up 1.5% of its mass. We examine whether the observed kinematics are caused by a collection of stellar mass BHs by modeling an extended dark mass as a Plummer profile. The upper limit on the size scale of the extended mass is 0.56 pc (95% confidence), which does not rule out an extended mass. There is compelling evidence that B023-G078 is the tidally stripped nucleus of a galaxy with a stellar mass >109 M ⊙, including its high-mass, two-component luminosity profile, color, metallicity gradient, and spread in metallicity. Given the emerging evidence that the central BH occupation fraction of >109 M ⊙ galaxies is high, the most plausible interpretation of the kinematic data is that B023-G078 hosts a central BH. This makes it the strongest BH detection in a lower-mass (<107 M ⊙) stripped nucleus, and one of the few dynamically detected intermediate-mass BHs.