A new strong-lensing galaxy at z= 0.066: another elliptical galaxy with a lightweight IMF
A new strong-lensing galaxy at z= 0.066: another elliptical galaxy with a lightweight IMF
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DOI：
10.1093/mnras/sty1188
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发表时间：
2018-03
影响因子：
4.8
通讯作者：
William P. Collier;Russell J. Smith;J. Lucey
中科院分区：
文献类型：
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作者：
William P. Collier;Russell J. Smith;J. Lucey
我们报告了一种新的低红移星系级引力透镜的发现，该透镜是通过对公开的 MUSE 观测结果进行系统搜索而确定的。透镜星系 2MASXJ04035024-0239275 是一个 z = 0.06604 的巨大椭圆星系，速度色散为 σ = 314 km s−1。透镜源的红移为 0.19165，并在透镜中心的两侧形成一对明亮的图像。爱因斯坦半径为1.5角秒，推算为1.8kpc，这只是星系有效半径的四分之一。在对估计的 19% 暗物质贡献进行校正后，我们发现透镜效应产生的恒星质量光比与银河系初始质量函数 (IMF) 的预期一致。将新系统与三个先前研究的具有相似 σ 的低红移透镜相结合，得出的平均质量过剩因子（相对于 Kroupa IMF）为 ⟨α⟩ = 1.09±0.08。对于所有四个系统，大质量椭圆星系的 α 固有散射可限制在 <0.32（置信度为 90%）。
We report the discovery of a new low-redshift galaxy-scale gravitational lens, identified from a systematic search of publicly available MUSE observations. The lens galaxy, 2MASXJ04035024-0239275, is a giant elliptical at z = 0.06604 with a velocity dispersion of σ = 314 km s−1. The lensed source has a redshift of 0.19165 and forms a pair of bright images on either side of the lens centre. The Einstein radius is 1.5 arcsec, projecting to 1.8 kpc, which is just one quarter of the galaxy effective radius. After correcting for an estimated 19 per cent dark matter contribution, we find that the stellar mass-to-light ratio from lensing is consistent with that expected for a Milky Way initial mass function (IMF). Combining the new system with three previously-studied low-redshift lenses of similar σ, the derived mean mass excess factor (relative to a Kroupa IMF) is ⟨α⟩ = 1.09±0.08. With all four systems, the intrinsic scatter in α for massive elliptical galaxies can be limited to <0.32, at 90 per cent confidence.