A MULTICOLOR PHOTOMETRIC STUDY OF THE GALAXY CLUSTER A2589: DYNAMICS, LUMINOSITY FUNCTION, AND STAR FORMATION HISTORY
A MULTICOLOR PHOTOMETRIC STUDY OF THE GALAXY CLUSTER A2589: DYNAMICS, LUMINOSITY FUNCTION, AND STAR FORMATION HISTORY
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DOI：
10.1088/0004-6256/141/3/99
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发表时间：
2011-01
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通讯作者：
Shun-Fang Liu;Q. Yuan;Yanbin Yang;Jun Ma;Zhao-ji Jiang;Jianghua Wu;Zhenyu Wu;Jian-sheng Chen
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文献类型：
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作者：
Shun-Fang Liu;Q. Yuan;Yanbin Yang;Jun Ma;Zhao-ji Jiang;Jianghua Wu;Zhenyu Wu;Jian-sheng Chen
平滑的X射线形态和在A2589中心没有探测到射电源表明它是一个典型的松弛规则星系团。本文介绍了A2589（z = 0.0414）在北京-亚利桑那-台湾-康涅狄格（BATC）系统中的15个中间带分光光度法，该系统覆盖了3000 - 10000毫微米的光波长范围。超过5000个源的光谱能量分布（SED）在大约1 ° 2的场中达到了20兆格。A2589也被斯隆数字巡天（SDSS）以测光模式覆盖。对BATC观测到的星系与SDSS测光表进行交叉识别，得到1199个亮度大于i = 19.5等的星系，其中68个成员星系具有已知的光谱红移，结合SDSS五波段测光数据和BATC SEDs，对这些星系进行光度红移筛选，得到暗成员星系。色-星等关系是对早型星系团的进一步限制。结果，106个星系被新选为成员星系。成员星系的空间分布表现出南北向的伸长，这与X射线亮度轮廓和中央cD星系NGC 7647的取向一致。根据星系团的位置和径向速度，没有检测到任何子结构，表明A2589是一个很好的弛豫系统。A2589的光度函数在MR 10 - 20等处有一个峰值，在MR 10 - 19等处有一个下降。利用演化的粒子数合成模型PEGASE，研究了68个已被光谱证实的成员星系的星星形成特性的环境效应。异常微弱的星系往往有较长的时间尺度的星星形成，较短的平均恒星年龄，和较低的金属在星际介质中，这可以解释在一个层次的宇宙学场景的背景下。
Smooth X-ray morphology and non-detection of a radio source at the center of A2589 indicate that it is a typical case of a well-relaxed regular galaxy cluster. In this paper, we present a multicolor photometry for A2589 (z = 0.0414) with 15 intermediate bands in the Beijing–Arizona–Taiwan–Connecticut (BATC) system which covers an optical wavelength range from 3000 Å to 10000 Å. The spectral energy distributions (SEDs) for more than 5000 sources are achieved down to V ∼ 20 mag in about a 1 deg2 field. A2589 has also been covered by the Sloan Digital Sky Survey (SDSS) in photometric mode only. A cross-identification of the BATC-detected galaxies with the SDSS photometric catalog yields 1199 galaxies brighter than i = 19.5 mag, among which 68 member galaxies with known spectroscopic redshifts are found. After combining the SDSS five-band photometric data and the BATC SEDs, photometric redshift is applied to these galaxies to select faint member galaxies. The color–magnitude relation is taken as a further restriction of early-type cluster galaxies. As a result, 106 galaxies are newly selected as member galaxies. Spatial distribution of member galaxies shows a north–south elongation which agrees with the X-ray brightness profile and the orientation of central cD galaxy, NGC 7647. No substructures are detected on the basis of positions and radial velocities of cluster galaxies, indicating that A2589 is a well-relaxed system. The luminosity function of A2589 exhibits a peak at MR ∼ −20 mag and a dip at MR ∼ −19 mag. The low-density outer regions are the preferred habitat of faint galaxies. With the evolutionary population synthesis model, PEGASE, the environmental effect on the star formation properties for 68 spectroscopically confirmed member galaxies is studied. The outlier faint galaxies tend to have longer timescales of star formation, shorter mean stellar ages, and lower metallicities in the interstellar medium, which can be interpreted in the context of a hierarchical cosmological scenario.