The ALMA Discovery of the Rotating Disk and Fast Outflow of Cold Molecular Gas in NGC 1275
The ALMA Discovery of the Rotating Disk and Fast Outflow of Cold Molecular Gas in NGC 1275
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DOI：
10.3847/1538-4357/ab3e6e
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发表时间：
2019-05
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通讯作者：
H. Nagai;K. Onishi;N. Kawakatu;Y. Fujita;M. Kino;Y. Fukazawa;J. Lim;W. Forman;J. Vrtilek;K. Nakanishi;H. Noda;K. Asada;K. Wajima;Y. Ohyama;L. David;K. Daikuhara
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作者：
H. Nagai;K. Onishi;N. Kawakatu;Y. Fujita;M. Kino;Y. Fukazawa;J. Lim;W. Forman;J. Vrtilek;K. Nakanishi;H. Noda;K. Asada;K. Wajima;Y. Ohyama;L. David;K. Daikuhara
我们利用阿塔卡马大型毫米/亚毫米阵列观测了附近射电星系/最亮星团星系（BCG）NGC 1275中的CO（2−1）、HCN（3−2）和HCO+（3−2）线，空间分辨率为200 pc。在之前的观测中，CO（2−1）的辐射被探测到是在千秒差距尺度上东西方向的放射状细丝。我们解决了内部的灯丝，并发现它不能代表一个简单的下降流在一个亚千秒差距的规模。观察到的复杂性质的灯丝类似于冷混沌吸积的数值模拟预测的冷气体结构。在中心100 pc内，我们探测到一个分子气体的旋转盘，其质量为108 M。这是第一个证据表明，存在一个巨大的冷气盘在这个空间尺度上的BCGs。粗略的估计表明，冷气体的吸积速率可能高于热气体。圆盘旋转轴与无线电射流轴大致一致。这可能表明，冷气盘与最里面的吸积盘是物理连接的，后者负责喷射发射。我们还检测到HCN（3−2）和HCO+（3−2）光谱中的吸收特征，而这些吸收特征主要是由尺寸为1.2 pc的喷流辐射的射电连续辐射。吸收特征比系统速度蓝移了300-600 km s−1，表明存在活动星系核（AGN）流出的气体。我们讨论了活动星系核与冷吸积的关系，蓝移吸收的起源，以及用分子气体动力学估算黑洞质量。
We present observations using the Atacama Large Millimeter/submillimeter Array of the CO(2−1), HCN(3−2), and HCO+(3−2) lines in the nearby radio galaxy/brightest cluster galaxy (BCG) NGC 1275 with a spatial resolution of ∼20 pc. In previous observations, the CO(2−1) emission was detected as radial filaments lying in the east–west direction on a kiloparsec scale. We resolved the inner filament and found that it cannot be represented by a simple infalling stream on a sub-kiloparsec scale. The observed complex nature of the filament resembles the cold gas structure predicted by numerical simulations of cold chaotic accretion. Within the central 100 pc, we detected a rotational disk of molecular gas whose mass is ∼108 M⊙. This is the first evidence of the presence of a massive cold gas disk on this spatial scale for BCGs. A crude estimate suggests that the accretion rate of the cold gas can be higher than that of hot gas. The disk rotation axis is approximately consistent with the radio-jet axis. This probably suggests that the cold gas disk is physically connected to the innermost accretion disk, which is responsible for jet launching. We also detected absorption features in the HCN(3−2) and HCO+(3−2) spectra against the radio continuum emission mostly radiated by a jet of size ∼1.2 pc. The absorption features are blueshifted from the systemic velocity by ∼300–600 km s−1, suggesting the presence of outflowing gas from the active galactic nucleus (AGN). We discuss the relation of the AGN feeding with cold accretion, the origin of blueshifted absorption, and an estimate of the black hole mass using molecular gas dynamics.