The Two-sided Jet Structures of NGC 1052 at Scales from 300 to 4 × 107 Schwarzschild Radii
The Two-sided Jet Structures of NGC 1052 at Scales from 300 to 4 × 107 Schwarzschild Radii
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DOI：
10.3847/1538-3881/ab465b
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发表时间：
2019-09
期刊：
影响因子：
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通讯作者：
S. Nakahara;A. Doi;Y. Murata;M. Nakamura;K. Hada;K. Asada;S. Sawada-Satoh;S. Kameno
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文献类型：
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作者：
S. Nakahara;A. Doi;Y. Murata;M. Nakamura;K. Hada;K. Asada;S. Sawada-Satoh;S. Kameno
我们研究了射电星系NGC 1052中喷流宽度随喷流距离沿着的分布，其径向距离在中心引擎的10300和4 × 107史瓦西半径（RS）之间，喷流的靠近和远离两侧。喷流的宽度是用甚长基线干涉测量（VLBI）空间观测计划、甚长基线阵列和甚大阵列获得的图像测量的。在整个测量距离范围内，后退喷流的喷流宽度剖面显然与接近喷流的喷流宽度剖面一致，这表明至少在中心黑洞的引力影响范围内是对称的。喷流宽度轮廓的幂律指数a（wjet ‡ ra，其中wjet是喷流宽度，r是距中央发动机的距离，单位为RS）显然显示出从0.00到0.01的过渡，即，喷流结构为圆柱-圆锥形，距离为101 × 104 RS。小距离处的圆柱形喷流形状让人想起3C 84中最里面的喷流。NGC 1052和3C 84的中央引擎都被致密物质包围，其中一部分被电离，导致大量的自由-自由吸收。
We investigated the jet width profile with distance along the jet in the nearby radio galaxy NGC 1052 at radial distances between ∼300 and 4 × 107 Schwarzschild radii (RS) from the central engine on both their approaching and receding jet sides. The width of jets was measured in images obtained with the Very Long Baseline Interferometry (VLBI) Space Observatory Programme, the Very Long Baseline Array, and the Very Large Array. The jet width profiles of receding jets are apparently consistent with those of approaching jets throughout the measuring distance ranges, indicating symmetry at least up to the sphere of gravitational influence of the central black hole. The power-law index a of the jet width profile (wjet ∝ ra, where wjet is the jet width, r is the distance from the central engine in the unit of RS) apparently shows a transition from a ∼ 0 to a ∼ 1, i.e., the cylindrical-to-conical jet structures, at a distance of ∼1 × 104RS. The cylindrical jet shape at small distances is reminiscent of the innermost jets in 3C 84. Both the central engines of NGC 1052 and 3C 84 are surrounded by dense material, part of which is ionized and causes heavy free–free absorption.