Direct Proof for the Formation of Proto-Elliptical Galaxies and Their Origin

原椭圆星系形成及其起源的直接证明

基本信息

批准号：
16540223
负责人：
ARIMOTO Nobuo
金额：
$ 2.37万
依托单位：
National Astronomical Observatory of Japan
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540223/
关键词：
Elliptical Galaxies Galaxy Formation Galaxy Evolution BzK Galaxies Star Formation Rate Stellar Populations Primeval Galaxies ERO銀河星形成高赤方偏移銀河星間ダスト

项目摘要

We have developed an effective way to cull the candidates for star forming elliptical galaxies at high redshift, and have successfully discovered numerous candidates (sBzK and pBzK galaxies at 1.4<z<2.5) by using the Subaru/Suprime-Camera. sBzK galaxies are currently under intense star forming activity, and their stellar masses, spatial densities, and clustering properties are comparable to those of nearby massive ellipticals. pBzK galaxies are post starburst galaxies with comparable stellar masses to sBzKs and their clustering and spatial densities are as large as giant ellipticals in clusters of galaxies of the local universe. These results suggest that BzK galaxies are elliptical galaxies in their major formation epoch; sBzKs evolve to pBzKs, then to EROs at z~1, and finally to passive elliptical galaxies at z-0. To confirm high SFRs inferred from SED of sBzK galaxies, we measured 1.2mm flux of 2 sBzKs to find very high SFRs as 500~1500 solar mass per year, supporting our previous f … More indings of active star forming nature of sBzK galaxies. These galaxies are more luminous in K-band than Scuba sources at z~2, from which one can learn that sBzKs had a short-period evolutionary stage of very active star formation with dense dust clouds. We have also observed one sBzK galaxy, BzK-15504 with near infrared 3D spectrograph SINFONI on VLT for the first time of this kind of observation of high redshift galaxies. Surprisingly, this galaxy has a rapidly rotating disk of comparable mass and rotational velocity to those of the Milky Way disk, and is now in the stage of bulge formation with gas infall of considerable amount into a central massive black hole. It is not clear is if this massive gas disk is stable, or the galaxy will eventually merge with other galaxies to form a single massive elliptical galaxy.This study strongly suggests the following scenario for the formation and evolution of massive elliptical galaxies: The formation of massive ellipticals occur at z~2 universe, before which mass assembly has not yet completed and galaxies have relatively smaller SFRs (due to a lack of sufficient gas available). Once formed at z~2, galaxies are detected as sBzK galaxies, which then evolve into pBzK galaxies, ERO galaxies, and finally giant elliptical galaxies on the Hubble sequence. The timescale of this process would depend on the galaxy environment in the sense that galaxies evolve much quicker in dense environment and more massive galaxies evolve more rapidly. Thus, our finding of the formation epoch of massive ellipticals at z~2 should correspond to the general field and the formation epoch could be much earlier in the cluster environments. Thus there is a possibility to discover clustering of star forming dusty galaxies at much higher redshift. Identifying such proto-clusters of galaxies would tell a lot about elliptical galaxies in their infant ages. Less

我们已经开发了一种有效的方法，以高红移来挑选恒星形成椭圆星系的候选者，并通过使用Subaru/suprime-camera成功地发现了许多候选者（SBZK和PBZK星系为1.4 <z <2.5）。 SBZK星系目前处于强烈的恒星形成活动中，其恒星质量，空间密度和聚类特性与近较大的椭圆形相当。 PBZK星系是后星系星系，具有与SBZK相当的恒星质量，它们的聚类和空间密度与当地宇宙星系簇中的巨型椭圆形一样大。这些结果表明，BZK星系是其主要地层时期的椭圆星系。 SBZKS演变为PBZK，然后在Z〜1处演变为Eros，最后是Z-0的被动椭圆星系。为了确认从SBZK星系的SED推断出的高SFR，我们测量了1.2mm的2 SBZKS，以每年的SFRS为500〜1500太阳能质量，从而支持我们以前的F…更多的F ...更多的f，更多地指示SBZK星系的活性星形成性质。这些星系在K波段中比Z〜2处的水肺源更发光，从中可以获得SBZK具有非常活跃的恒星形成的短期进化阶段，并具有致密的尘埃云。我们还观察到一个SBZK Galaxy，BZK-15504，在VLT上，VLT上的接近红外3D光谱sinfoni首次观察到高红移星系。令人惊讶的是，该星系具有与银河系磁盘的质量和旋转速度的快速旋转磁盘，现在正处于凸起形成的阶段，考虑因素的气体为中心的巨大黑洞。目前尚不清楚该大型气盘是否稳定，或者银河系最终将与其他星系合并以形成一个巨大的椭圆形星系。这项研究强烈建议形成和演变以下情况，以形成和演变：大规模的椭圆形星系的形成和演变：在Z〜2 Universe中的大规模椭圆形出现，并且在Z〜2群体中发生了较小的元素，并在此范围内，并在此范围内又有了大量的元素（尚未达到群体（尚未达到）（尚未达到群体），并在该元素中尚未达到群体（尚未达到的天才）（天哪（天）（天体）足够的气体）。一旦在Z〜2形成，将星系检测为SBZK星系，然后演变为PBZK星系，ERO星系，最后是哈勃序列上的巨型椭圆星系。这个过程的时间表将取决于星系环境，因为星系在密集的环境中更快地发展，并且更大的星系进化得更快。这，我们发现Z〜2处的大规模椭圆形的地层时期应与一般场相对应，并且在群集环境中形成时期可能更早。有可能在更高的红移中发现恒星形成尘土飞扬的星系的聚类。识别出星系的这种原始群体将在婴儿年龄中讲述很多有关椭圆星系的信息。较少的