标题： 大规模调查。 XX。 对巨型射电星系NGC 315的超大质量黑洞质量和固有星系形状的三轴恒星动力学测量 显示英文标题

标题： The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315

摘要： 我们介绍了对大质量射电星系NGC 315的超大质量黑洞质量以及恒星晕的固有形状的新动态测量结果，这是MASSIVE调查的一部分。 来自Gemini和McDonald天文台的积分场光谱仪的高信噪比光谱提供了在中心$304$空间区间的恒星运动学测量，从中心${\sim}0.3''$延伸到$30''$。 使用${\sim} 2300$运动学约束，我们利用TriOS代码进行三轴恒星轨道建模，并通过贝叶斯方案搜索${\sim}$15,000个星系模型，同时测量六个质量及固有形状参数。 NGC 315 是三轴且高度拉长的，其中间轴与长轴比为$p=0.854$，短轴与长轴比为$q=0.833$，三轴性参数为$T=0.89$。 从我们的恒星运动学推断出的黑洞质量为$M_\mathrm{BH} = \left(3.0 {\pm} 0.3\right) {\times} 10^{9}\ M_\odot$，这高于从CO运动学推断出的$M_\mathrm{BH}=(1.96^{+0.30}_{-0.13}) {\times} 10^{9} M_\odot$（缩放到我们的距离）。 当比较七个多重测量的星系时，来自恒星和CO运动学的$M_\mathrm{BH}$，我们发现两种示踪物在$M_\mathrm{BH}$上存在固有散度为0.28 dex，并且在当前数据中未检测到两种方法之间的统计显著偏差。 暗示的黑洞阴影大小（${\approx} 4.7\, \mu{\rm as}$）和NGC 315相对较高的毫米波通量使该星系成为未来视准角成像研究的理想候选。 显示英文摘要

摘要： We present a new dynamical measurement of the supermassive black hole mass and intrinsic shape of the stellar halo of the massive radio galaxy NGC 315 as part of the MASSIVE survey. High signal-to-noise ratio spectra from integral-field spectrographs at the Gemini and McDonald Observatories provide stellar kinematic measurements in $304$ spatial bins from the central ${\sim}0.3''$ out to $30''$. Using ${\sim} 2300$ kinematic constraints, we perform triaxial stellar orbit modeling with the TriOS code and search over ${\sim}$15,000 galaxy models with a Bayesian scheme to simultaneously measure six mass and intrinsic shape parameters. NGC 315 is triaxial and highly prolate, with middle-to-long and short-to-long axis ratios of $p=0.854$ and $q=0.833$ and a triaxiality parameter of $T=0.89$. The black hole mass inferred from our stellar kinematics is $M_\mathrm{BH} = \left(3.0 {\pm} 0.3\right) {\times} 10^{9}\ M_\odot$, which is higher than $M_\mathrm{BH}=(1.96^{+0.30}_{-0.13}) {\times} 10^{9} M_\odot$ inferred from CO kinematics (scaled to our distance). When the seven galaxies with $M_\mathrm{BH}$ measurements from both stellar and CO kinematics are compared, we find an intrinsic scatter of 0.28 dex in $M_\mathrm{BH}$ from the two tracers and do not detect statistically significant biases between the two methods in the current data. The implied black hole shadow size (${\approx} 4.7\, \mu{\rm as}$) and the relatively high millimeter flux of NGC 315 makes this galaxy a prime candidate for future horizon-size imaging studies.