A quartet of black holes and a missing duo: probing the low end of the MBH–σ relation with the adaptive optics assisted integral-field spectroscopy
A quartet of black holes and a missing duo: probing the low end of the MBH–σ relation with the adaptive optics assisted integral-field spectroscopy
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DOI：
10.1093/mnras/sty778
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发表时间：
2018-03
影响因子：
4.8
通讯作者：
D. Krajnovi'c;M. Cappellari;R. McDermid;R. McDermid;S. Thater;K. Nyland;P. Zeeuw;P. Zeeuw;J. Falcón-Barroso;J. Falcón-Barroso;S. Khochfar;H. Kuntschner;M. Sarzi;L. Young
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作者：
D. Krajnovi'c;M. Cappellari;R. McDermid;R. McDermid;S. Thater;K. Nyland;P. Zeeuw;P. Zeeuw;J. Falcón-Barroso;J. Falcón-Barroso;S. Khochfar;H. Kuntschner;M. Sarzi;L. Young
我们给出了六个附近快速旋转的早期星系（NGC4339, NGC4434, NGC4474, NGC4551， NGC4578和NGC4762）中超大质量黑洞的质量估计，有效恒星速度色散约为100 km/s。我们使用GEMINI/NIFS近红外激光制导自适应光学观测来获得星系核中的恒星运动学，并使用ATLAS3D巡天的SAURON观测来获得大尺度运动学。建立了轴对称的Jeans各向异性模型和轴对称的Schwarzschild动力学模型。两种建模方法都能在1-2西格玛置信水平内恢复一致的轨道各向异性和黑洞质量，除了一个星系的差异刚刚超过3西格玛水平。两个黑洞（NGC4339和NGC4434）是目前黑洞质量-速度色散关系中最大的异常值之一，质量分别为$(4.3^{+4.8}_{-2.3})\times10^7$和$(7.0^{+2.0}_{-2.8})\times10^7$ M $_\odot$ （$3\sigma$置信水平）。NGC4578和NGC4762中的黑洞分别与$(1.9^{+0.6}_{-1.4})\times10^7$和$(2.3^{+0.9}_{-0.6})\times10^7$ M $_\odot$的质量成比例关系（3 σ置信水平）。对于两个星系（NGC4474和NGC4551），我们能够给出它们黑洞质量的上限（分别为$<7\times10^6$和$<5\times10^6$ M $_\odot$，置信水平为$3\sigma$）。这些星系的运动学清楚地表明，中心速度色散分别在35pc和80pc的半径内下降。这些液滴不可能与冷恒星结构有关，我们的数据也没有足够的分辨率来排除质量比预测小一个数量级的黑洞。在球坐标中参数化轨道分布，黑洞附近的特征是各向同性或轻微的切向各向异性。
We present mass estimates of supermassive black holes in six nearby fast rotating early-type galaxies (NGC4339, NGC4434, NGC4474, NGC4551, NGC4578 and NGC4762) with effective stellar velocity dispersion around 100 km/s. We use near-infrared laser-guide adaptive optics observations with the GEMINI/NIFS to derive stellar kinematics in the galactic nuclei, and SAURON observations from the ATLAS3D Survey for large-scale kinematics. We build axisymmetric Jeans Anisotropic Models and axisymmetric Schwarzschild dynamical models. Both modelling approaches recover consistent orbital anisotropies and black hole masses within 1-2sigma confidence level, except for one galaxy for which the difference is just above the 3sigma level. Two black holes (NGC4339 and NGC4434) are amongst the largest outliers from the current black hole mass - velocity dispersion relation, with masses of $(4.3^{+4.8}_{-2.3})\times10^7$ and $(7.0^{+2.0}_{-2.8})\times10^7$ M$_\odot$, respectively ($3\sigma$ confidence level). The black holes in NGC4578 and NGC4762 lie on the scaling relation with masses of $(1.9^{+0.6}_{-1.4})\times10^7$ and $(2.3^{+0.9}_{-0.6})\times10^7$ M$_\odot$, respectively (3sigma confidence level). For two galaxies (NGC4474 and NGC4551) we are able to place upper limits on their black holes masses ($<7\times10^6$ and $<5\times10^6$ M$_\odot$, respectively, $3\sigma$ confidence level). The kinematics for these galaxies clearly indicate central velocity dispersion drops within a radius of 35 pc and 80 pc, respectively. These drops cannot be associated with cold stellar structures and our data do not have the resolution to exclude black holes with masses an order of magnitude smaller than the predictions. Parametrising the orbital distribution in spherical coordinates, the vicinity of the black holes is characterised by isotropic or mildly tangential anisotropy.