• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Astrophysical journal >OPTICAL AND NEAR-INFRARED STRUCTURAL PROPERTIES OF CLUSTER GALAXIES AT z ～ 0.3
【24h】

OPTICAL AND NEAR-INFRARED STRUCTURAL PROPERTIES OF CLUSTER GALAXIES AT z ～ 0.3

机译：z〜0.3时的星系团的光学和近红外结构性质

获取原文
获取原文并翻译 | 示例
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Structural parameters (half-light radius r_e, mean effective surface brightness <μ>_e, and Sersic index n, parameterizing the light profile shape) are derived for a sample of galaxies in the rich cluster AC 118 at z = 0.31, so far the largest (N = 93) sample of galaxies at intermediate redshift with structural parameters measured in the near-infrared. The parameters are obtained in two optical wavebands (V and R) and in the K band, corresponding approximately to the B, V, and H rest frame. The distributions of r_e at z = 0.31 match those for the Coma Cluster (i.e., for the local universe) both in the optical and in the NIR. The K-band distribution is of particular interest, since the NIR light mimics the mass distribution of galaxies. The similarity of the distributions for the two clusters (AC 118 and Coma) proves that the galaxies at the bright end of the luminosity function did not significantly change their sizes since z ～ 0.3 to the present epoch. The ratio of the optical to the NIR half-light radius shows a marked trend with the shape of the light profile (Sersic index n). In galaxies with n approx> 4 (typical bright ellipticals) r_(e,NIR) ～ 0.6r_(e,opt), while the average ratio is 0.8 for galaxies with lower n (typical disk systems). Moreover, the NIR Sersic index is systematically larger than in the optical for n approx< 4. These results, translated into optical and optical-NIR color gradients, imply that the optical color gradients at z ～ 0.3 are similar to those of nearby galaxies. The optical-NIR color gradients are in the average larger, ranging from -0.73 mag dex~(-1) for n approx< 4 to -0.35 mag dex~(-1) for n approx> 4. Models with "pure age" or "pure metallicity" gradients are unable to reconcile our color gradients estimates with observations at z ～ 0, but we argue that the combined effects of age and metallicity might explain consistently the observed data: passive evolution (plus the possible effect of dust absorption) may account for the differences between the optical and NIR structural properties. The lack of any major change in r_(e,NIR) since z ～ 0.3 suggests that merging involving bright galaxies did not play a significant role in the last ～4.4 Gyr (Ω_M = 0.3, Ω_Λ = 0, H_0 = 50 km s~(-1) Mpc~(-1)). The results of the present paper will be applied to the study of the scaling laws in subsequent works.
机译：对于z = 0.31的富星团AC 118中的一个星系样本，得出了结构参数（半光半径r_e，平均有效表面亮度μ_e和Sesic指数n，将光轮廓形状参数化）。中间红移时最大的星系样本（N = 93），其结构参数在近红外中测量。在两个光波段（V和R）和K波段中获得参数，大约对应于B，V和H静止帧。在z = 0.31时，r_e的分布在光学和近红外中均与昏迷星团（即局部宇宙）的分布匹配。 K波段分布特别令人关注，因为NIR光模仿星系的质量分布。两个星团（AC 118和彗星）的分布相似，证明从z〜0.3到现在，光度函数亮端的星系大小没有明显改变。光学与NIR半光半径之比随光轮廓的形状（Sersic指数n）呈明显趋势。在n大约大于4（典型的亮椭圆形）的星系中，r_（e，NIR）〜0.6r_（e，opt），而对于n较低的星系（典型的圆盘系统），平均比率为0.8。此外，对于n约<4，NIR Sersic指数在系统上大于光学系统。这些结果转化为光学和光学NIR颜色梯度，这意味着z〜0.3处的光学颜色梯度与附近星系的相似。 NIR光学平均颜色梯度较大，范围从n大约<4的-0.73 mag dex〜（-1）到n大约> 4的-0.35 mag dex〜（-1）。或“纯金属性”梯度无法将我们的颜色梯度估计值与z〜0处的观测值相吻合，但我们认为年龄和金属性的综合影响可能会一致地解释观测到的数据：被动演变（加上尘埃吸收的可能影响）可能解释了光学和近红外结构特性之间的差异。自z〜0.3以来，r_（e，NIR）几乎没有任何重大变化，这表明与亮星系有关的合并在最后一个〜4.4 Gyr中没有显着作用（Ω_M= 0.3，Ω_Λ= 0，H_0 = 50 km s〜 （-1）Mpc〜（-1））。本文的结果将在以后的工作中应用于比例定律的研究。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号