论文标题
在z = 1.7的原始群集中发现分子气体加油星系生长
Discovery of molecular gas fueling galaxy growth in a protocluster at z=1.7
论文作者
论文摘要
基于ALMA频段3对CO（2-1）线转变的观察结果，我们报告了三个新的气体富含气（M_H2〜1.5-4.8 x 10^10^10 m_sun，范围内的SFR，〜5-100 m_sun/yr/yr）星系在Z = 1.7处的过度密度区域，其中包括八个eppectroscoscopocoposcopoposcopoposcopepopecopepopopocoposcopeptions。这将导致总共11个确认的过度密度成员，预计距离约为1.15 mpc，在红移范围内DZ = 0.012。在简单的假设下，我们估计该系统的总质量为> = 3-6 x 10^13 m_sun，并表明它可能会在z = 0处演变为> 〜10^14 m_sun群集。该密度包括一个强大的compton-thick-thick-thick-thick-thick-thick-thick-thick-thick-thick-type type II（frii）type ii（frii）无线电，我们发现了一个大型gasev，我们发现了10^2（MORECULAD）2（MORECULAD）〜2 m_sun）。我们将FRII解决的CO发射拟合了2-D高斯模型，其主要（次要）轴为〜27（〜17）kpc，这比光学静止框架发射大〜3。在简单的边缘磁盘形态的假设下，我们发现星系星际介质朝向〜5.5 x 10^23 cm^-2的细胞核产生柱密度。这样的密集ISM可能会对在X射线（N_（H，X）〜1.5 x 10^24 cm^-2）中测得的总核遮挡做出重大贡献。该来源的速度图揭示了垂直于射线喷射的气体的旋转运动。 FRII位于结构构件的投影空间分布的中心，其速度偏移与红移分布的峰值相抵消在结构的速度分散体内。所有这些，再加上周围的大量气体，其出色的质量为〜3 x 10^11 m_sun，SFR，〜200-600 m_sun/yr和强大的无线电对X射线发射，这表明该来源可能是未来最亮的星系的可能的祖先。
Based on ALMA Band 3 observations of the CO(2-1) line transition, we report the discovery of three new gas-rich (M_H2 ~ 1.5-4.8 x 10^10 M_sun, SFRs in the range ~5-100 M_sun/yr) galaxies in an overdense region at z=1.7, that already contains eight spectroscopically confirmed members. This leads to a total of 11 confirmed overdensity members, within a projected distance of ~ 1.15 Mpc and in a redshift range of Dz = 0.012. Under simple assumptions, we estimate that the system has a total mass of >= 3-6 x 10^13 M_sun, and show that it will likely evolve into a >~ 10^14 M_sun cluster at z = 0. The overdensity includes a powerful Compton-thick Fanaroff-Riley type II (FRII) radio-galaxy, around which we discovered a large molecular gas reservoir (M_H2 ~ 2 x 10^11 M_sun). We fitted the FRII resolved CO emission with a 2-D Gaussian model with major (minor) axis of ~ 27 (~ 17) kpc, that is a factor of ~3 larger than the optical rest-frame emission. Under the assumption of a simple edge-on disk morphology, we find that the galaxy interstellar medium produces a column density towards the nucleus of ~ 5.5 x 10^23 cm^-2. Such a dense ISM may then contribute significantly to the total nuclear obscuration measured in the X-rays (N_(H,X) ~ 1.5 x 10^24 cm^-2) in addition to a small, pc-scale absorber around the central engine. The velocity map of this source unveils a rotational motion of the gas that is perpendicular to the radio-jets. The FRII is located at the center of the projected spatial distribution of the structure members, and its velocity offset from the peak of the redshift distribution is well within the structure's velocity dispersion. All this, coupled with the large amount of gas around the FRII, its stellar mass of ~ 3 x 10^11 M_sun, SFR of ~ 200-600 M_sun/yr, and powerful radio-to-X-ray emission, suggests that this source is the likely progenitor of the future brightest cluster galaxy.
