The Centers of Early-Type Galaxies with Hubble Space Telescope. VI. Bimodal Central Surface Brightness Profiles
The Centers of Early-Type Galaxies with Hubble Space Telescope. VI. Bimodal Central Surface Brightness Profiles
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DOI：
10.1086/519229
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发表时间：
2006-09
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影响因子：
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通讯作者：
T. Lauer;K. Gebhardt;S. Faber;D. Richstone;S. Tremaine;J. Kormendy;M. Aller;R. Bender;A. Dressler;A. Filippenko;R. Green;L. Ho
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作者：
T. Lauer;K. Gebhardt;S. Faber;D. Richstone;S. Tremaine;J. Kormendy;M. Aller;R. Bender;A. Dressler;A. Filippenko;R. Green;L. Ho
我们结合了对早期型星系中心结构的几项HST研究，产生了大量的表面光度测量样本。选择的研究是那些使用“努克定律”来表征星系内部光分布的研究。样本包括我们小组之前发表的WFPC1和WFPC2 v波段观测，Rest等人的r波段WFPC2光度测量，Ravindranath等人和Quillen等人的NICMOS h波段光度测量，以及Laine等人的最亮星团WFPC2 i波段光度测量。基于参数和非参数分析，中心亮度曲线的对数斜率分布有力地证实了MV < -19的椭圆星系的中心结构是双峰的。在HST的分辨率极限下，大多数星系要么是幂律系统，其表面亮度有陡峭的尖峰，要么是核心系统，其内部有较浅的尖峰，其包络亮度分布更陡峭。两种形式之间的快速转变发生在光度范围-22 < MV < -20，在最高光度处占主导地位，在最低光度处占幂律。有一些“中间”系统，其尖峰斜率和总光度都落在核心/幂律过渡范围内，但它们很少见，并且不填充整个双峰分布。
We combine several HST investigations on the central structure of early-type galaxies to generate a large sample of surface photometry. The studies selected were those that used the "Nuker law" to characterize the inner light distributions of the galaxies. The sample comprises WFPC1 and WFPC2 V-band observations published earlier by our group, R-band WFPC2 photometry of Rest et al., NICMOS H-band photometry by Ravindranath et al. and Quillen et al., and the brightest cluster galaxy WFPC2 I-band photometry of Laine et al. The distribution of the logarithmic slopes of the central brightness profiles strongly affirms that the central structure of elliptical galaxies with MV < -19 is bimodal, based on both parametric and nonparametric analysis. At the HST resolution limit, most galaxies are either power-law systems, which have steep cusps in surface brightness, or core systems, which have shallow cusps interior to a steeper envelope brightness distribution. A rapid transition between the two forms occurs over the luminosity range -22 < MV < -20, with cores dominating at the highest luminosities and power laws at the lowest. There are a few "intermediate" systems that have both cusp slopes and total luminosities that fall within the core/power-law transition, but they are rare and do not fill in the overall bimodal distribution.