论文标题
从大型柱子中发现了两个爱因斯坦十字架 - 在孩子们的z> 1处的蓝色掘金星系
Discovery of two Einstein crosses from massive post--blue nugget galaxies at z>1 in KiDS
论文作者
论文摘要
我们报告了在KILO-AREVERY调查（儿童）的足迹中发现了两个爱因斯坦十字架（ECS）：儿童J232940-340922和儿童J122456+005048。使用Muse@vlt的整体场谱，我们确认它们的引力镜头性质。在这两种情况下，来源的四个光谱都清楚地表明了吸收特征的突出性，因此揭示了进化的恒星种群，恒星形成很小。两个系统的镜头模型假设带有外部剪切的奇异等温椭圆形（SIE）表明：1）位于Redshift $ z = 0.38 $和0.24的两个十字具有Einstein Radius $ R _ {\ rm E} = 5.2 $ KPC和5.4 kpc，分别为Einstein Radius $ r _ {\ rm E} = 5.2 $ kpc和5.4 kpc； 2）他们在半径半径内的预计暗物质分数为0.60和0.56（Chabrier IMF）； 3）来源是超紧凑的星系，$ r _ {\ rm e} \ sim0.9 $ kpc（在RedShift $ z _ {\ rm S} = 1.59 $）和$ r _ {\ rm e}这些结果不受潜在的质量密度假设的影响。由于尺寸，蓝色和吸收为主的光谱，通过光谱光谱分布拟合得出的低特异性星形成速率证实，我们认为这些ECS中的两个透镜源是蓝色掘金，朝向其淬灭阶段。
We report the discovery of two Einstein Crosses (ECs) in the footprint of the Kilo-Degree Survey (KiDS): KIDS J232940-340922 and KIDS J122456+005048. Using integral field spectroscopy from MUSE@VLT, we confirm their gravitational-lens nature. In both cases, the four spectra of the source clearly show a prominence of absorption features, hence revealing an evolved stellar population with little star formation. The lensing model of the two systems, assuming a singular isothermal ellipsoid (SIE) with external shear, shows that: 1) the two crosses, located at redshift $z=0.38$ and 0.24, have Einstein radius $R_{\rm E}=5.2$ kpc and 5.4 kpc, respectively; 2) their projected dark matter fractions inside the half effective radius are 0.60 and 0.56 (Chabrier IMF); 3) the sources are ultra-compact galaxies, $R_{\rm e}\sim0.9$ kpc (at redshift $z_{\rm s}=1.59$) and $R_{\rm e}\sim0.5$ kpc ($z_{\rm s}=1.10$), respectively. These results are unaffected by the underlying mass density assumption. Due to size, blue color and absorption-dominated spectra, corroborated by low specific star-formation rates derived from optical-NIR spectral energy distribution fitting, we argue that the two lensed sources in these ECs are blue nuggets migrating toward their quenching phase.
