论文标题
从0.04 <z <z <0.15的颜色选择样品中的紧凑星系和尺寸质量的星系分布，并补充了Ugrizyjhk光度红移
Compact galaxies and the size-mass galaxy distribution from a colour-selected sample at 0.04 < z < 0.15 supplemented by ugrizYJHK photometric redshifts
论文作者
论文摘要
尺寸质量星系分布是星系演化的关键诊断。大规模的紧凑星系是恒星形成的高红移阶段的潜在幸存遗物。其中一些在SDSS成像中几乎无法解决，因此未包含在星系样品中。为了克服这一点，从SDSS和UKIDSS光度法的组合中选择了一个样品，至r <17.8。这是使用颜色彩色选择完成的，然后通过使用缩放通量匹配（SFM）获得准确的光度红移（Photo-Z）。与光谱红移（SPEC-Z）相比，SFM仅获得0.0125的1-散射，仅具有0.3％的异常值（Delta：Ln（1+Z）> 0.06）。在2300平方英尺上获得0.04 <z <0.15的163186个星系样品。结合Spec-Z和Photo-Z。遵循Barro等人，log：sigma_1.5 = log：m _*-1.5log：reff用于定义紧凑性。紧凑星系的光谱完整性为76％（LOG：SIGMA_1.5> 10.5），而正常大小的星系为92％。这种差异主要归因于SDSS“光纤碰撞”，而不是主要星系样品选择的完整性。使用环境过度，这证实与正常大小的星系相比，在高密度环境中发现紧凑的静态星系的可能性更大。通过与3D-HST的高红移样品进行比较，log：sigma_1.5分布函数显示出显着的演变，这是与诸如eagle之类的模拟进行比较的令人信服的方式。紧凑型静态星系的数量密度从z〜2到log（n/mpc^-3）= - 5.3+-0.4在SDSS-IKIDSS样本中下降约30倍。不确定性以日志中的陡峭切割为主导：Sigma_1.5在使用此完整样本中最终证明了这一点。
The size-mass galaxy distribution is a key diagnostic for galaxy evolution. Massive compact galaxies are potential surviving relics of a high-redshift phase of star formation. Some of these could be nearly unresolved in SDSS imaging and thus not included in galaxy samples. To overcome this, a sample was selected from the combination of SDSS and UKIDSS photometry to r<17.8. This was done using colour-colour selection, and then by obtaining accurate photometric redshifts (photo-z) using scaled flux matching (SFM). Compared to spectroscopic redshifts (spec-z), SFM obtained a 1-sigma scatter of 0.0125 with only 0.3% outliers (Delta:ln(1+z)>0.06). A sample of 163186 galaxies was obtained with 0.04<z<0.15 over 2300 sq.deg. using a combination of spec-z and photo-z. Following Barro et al., log:Sigma_1.5=log:M_*-1.5log:reff was used to define compactness. The spectroscopic completeness was 76% for compact galaxies (log:Sigma_1.5>10.5) compared to 92% for normal-size galaxies. This difference is primarily attributed to SDSS `fibre collisions' and not the completeness of the main galaxy sample selection. Using environmental overdensities, this confirms that compact quiescent galaxies are significantly more likely to be found in high-density environments compared to normal-size galaxies. By comparison with a high-redshift sample from 3D-HST, log:Sigma_1.5 distribution functions show significant evolution, with this being a compelling way to compare with simulations such as EAGLE. The number density of compact quiescent galaxies drops by a factor of about 30 from z~2 to log(n/Mpc^-3)=-5.3+-0.4 in the SDSS-UKIDSS sample. The uncertainty is dominated by the steep cut off in log:Sigma_1.5, which is demonstrated conclusively using this complete sample.
