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arXiv 1601.05151astro-ph.GA
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NGC 1277中的一个正常超大质量黑洞

A normal supermassive black hole in NGC 1277

Alister W. Graham, Mark Durré, Giulia A. D. Savorgnan, Anne M. Medling, D. Batcheldor, Nicholas Scott, Beverly Watson, A. Marconi

摘要:

识别具有“过大质量”的黑洞的星系需要两个测量值:一个黑洞质量(M_bh)和一个宿主球体质量(M_sph,*)。这里我们提供了NGC 1277的测量结果。我们的结构分解显示NGC 1277是一个“经典”椭球体,其Sersic指数n=5.3,半光半径R_e=2.1 kpc,恒星质量为2.7 × 10 ^{11} M_sun(使用M_*/L_V=11.65,Martin-Navarro等人)。这个质量比最初报道的要大一个数量级。利用最新的(M_bh)-n,(M_bh)-(M_sph,*)和(M_bh)-sigma关系式,分别得到了预期的黑洞质量(0.57^{+1.29}_{-0.40})x10^9 M_sun、(1.58^{+4.04}_{-1.13})x10^9 M_sun和(2.27^{+4.04}_{-1.44})x10^9 M_sun(使用sigma=300 km/s),其中“影响范围”为0”.31。我们从凯克一号望远镜上的激光导星辅助自适应光学获得的新的运动学地图戏剧性地重申了这个星系图像中看到的内部,几乎是边缘的圆盘的存在。我们还报告说,这产生了一个大的速度切变(~400 km/s),穿过内部0”.2(70 pc),加上升高的sqrt{sigma^2+(V_rot)^2}值,穿过星系的内部3”.8x0”.6区域。我们新的多高斯展开(MGE)模型和Jeans各向异性MGE(JAM)分析难以匹配此扩展组件。我们的最佳黑洞质量是1.2 × 10^9 M_sun(M/L_V=12.3),尽管这可能是一个上限。这比最初报告的小一个数量级,比最近报告的小4倍。它给出的M_bh/M_sph,* 比值为0.45%,与在非矮早型星系中观测到的中值(~0.5%)和射程(0.1 ~ 5.0%)一致。这一结果强调了对内部磁盘的谨慎需要。

英文摘要:

The identification of galaxies with `overly massive' black holes requires two measurements: a black hole mass (M_bh) and a host spheroid mass (M_sph,*). Here we provide our measurements for NGC 1277. Our structural decomposition reveals that NGC 1277 is dominated by a `classical' spheroid with a Sersic index n=5.3, a half-light radius R_e=2.1 kpc, and a stellar mass of 2.7x10^{11} M_sun (using M_*/L_V=11.65, Martin-Navarro et al.). This mass is an order of magnitude greater than originally reported. Using the latest (M_bh)-n, (M_bh)-(M_sph,*) and (M_bh)-sigma relations, the expected black hole mass is respectively (0.57^{+1.29}_{-0.40})x10^9 M_sun, (1.58^{+4.04}_{-1.13})x10^9 M_sun, and (2.27^{+4.04}_{-1.44})x10^9 M_sun (using sigma=300 km/s) for which the `sphere-of-influence' is 0".31. Our new kinematical maps obtained from laser guide star assisted, adaptive optics on the Keck I Telescope dramatically reaffirm the presence of the inner, nearly edge-on, disk seen in this galaxy's image. We also report that this produces a large velocity shear (~400 km/s) across the inner 0".2 (70 pc) plus elevated values of sqrt{sigma^2+(V_rot)^2} across the inner 3".8x0".6 region of the galaxy. Our new multi-Gaussian expansion (MGE) models and Jeans Anisotropic MGE (JAM) analysis struggled to match this extended component. Our optimal black hole mass, albeit a probable upper limit because of the disk, is 1.2x10^9 M_sun (M/L_V=12.3). This is an order of magnitude smaller than originally reported and 4 times smaller than recently reported. It gives an M_bh/M_sph,* ratio of 0.45% in agreement with the median (~0.5%) and range (0.1 to 5.0%) observed in non-dwarf, early-type galaxies. This result highlights the need for caution with inner disks.

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