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外文期刊>The Astrophysical journal
>THE SL2S GALAXY-SCALE LENS SAMPLE. V. DARK MATTER HALOS AND STELLAR IMF OF MASSIVE EARLY-TYPE GALAXIES OUT TO REDSHIFT 0.8
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THE SL2S GALAXY-SCALE LENS SAMPLE. V. DARK MATTER HALOS AND STELLAR IMF OF MASSIVE EARLY-TYPE GALAXIES OUT TO REDSHIFT 0.8
We investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. We find that the dark matter mass projected within the inner 5 kpc increases for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M * = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.
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机译:我们研究了宇宙一半以上年龄的早期大型星系内部结构的宇宙演化。我们对来自强透镜遗留力调查和斯隆ACS透镜调查的81个强透镜样品进行了联合透镜和恒星动力学分析,并将结果与分层贝叶斯推断方法相结合,以测量暗物质质量和恒星初始质量函数的分布(IMF)分布在大规模早期星系中。考虑了镜头选择效果。我们发现,投射在内部5 kpc内的暗物质质量随着红移的增加而增加,随着恒星质量密度的增加而减小,但是沿着早期星系的演化轨迹大致恒定。平均暗物质斜率与Navarro-Frenk-White轮廓的斜率一致,但不受很好的约束。在log M * = 11.5时,恒星IMF归一化接近Salpeter IMF,并随着恒星质量的增加而强烈缩放。没有检测到IMF对红移或恒星质量密度的依赖性。暗物质质量和恒星质量密度之间的反相关性支持在更大质量的暗物质光环中合并更为频繁的想法。
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