arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1107.4093astro-ph.CO
收藏

红色序列星系团巡天2中星系中重子与暗物质关系的星系-星系透镜约束

Galaxy-galaxy lensing constraints on the relation between baryons and dark matter in galaxies in the Red Sequence Cluster Survey 2

Edo van Uitert, Henk Hoekstra, Malin Velander, David G. Gilbank, Michael D. Gladders, H. K. C. Yee

摘要:

我们提出的弱引力透镜的星系使用的成像数据,获得的第二次红色序列星系团巡天(RCS 2)的一部分的研究结果。为了与透镜的重子性质进行比较,我们在这里关注与SDSS的DR 7重叠的~300平方度。RCS 2的深度和图像质量使我们能够显着改善z>=0.3的发光星系的早期工作。从SDSS的动力学质量的比较显示出良好的相关性与透镜质量的早型星系。对于低光度(恒星质量)的早型星系,我们发现一个卫星的分数约为40%,迅速减少到10%以下的光度(恒星质量)增加。晚型的卫星部分具有在0- 15%范围内的值。我们发现在10 ^10 <L_r<10 ^11.5 Lsun范围内的早期型星系的维里质量大约是晚期型星系的5倍,质量标度为M_200 \propto L ^2.34 + 0.09\-0.16。我们还测量了维里质光比,发现当L_200<10^11 Lsun时,早期类型的值为M_200/L_200=42+-10,随着光度的增加,这个值增加到与星系群和星系团的观测值一致的值。对于晚型星系,我们发现M_(200)/L_(200)=17+-9。我们的测量还表明,当恒星质量M_*<10^11 Msun时,早型和晚型星系的晕质量相当,而当恒星质量较大时,早型星系的维里质量较高。最后,我们确定重子转换成恒星的效率。我们对早型星系的研究结果表明,当恒星质量为M_*,200 =10^12 Msun时,效率的变化最小约为10%。晚型星系的结果没有很好的约束,但确实表明了一个更大的值。(节略)

英文摘要:

We present the results of a study of weak gravitational lensing by galaxies using imaging data that were obtained as part of the second Red Sequence Cluster Survey (RCS2). In order to compare to the baryonic properties of the lenses we focus here on the ~300 square degrees that overlap with the DR7 of the SDSS. The depth and image quality of the RCS2 enables us to significantly improve upon earlier work for luminous galaxies at z>=0.3. Comparison with dynamical masses from the SDSS shows a good correlation with the lensing mass for early-type galaxies. For low luminosity (stellar mass) early-type galaxies we find a satellite fraction of ~40% which rapidly decreases to <10% with increasing luminosity (stellar mass). The satellite fraction of the late-types has a value in the range 0-15%. We find that early-types in the range 10^10<L_r<10^11.5 Lsun have virial masses that are about five times higher than those of late-type galaxies and that the mass scales as M_200 \propto L^2.34 +0.09 \ -0.16. We also measure the virial mass-to-light ratio, and find for L_200<10^11 Lsun a value of M_200/L_200=42+-10 for early-types, which increases for higher luminosities to values that are consistent with those observed for groups and clusters of galaxies. For late-type galaxies we find a lower value of M_200/L_200=17+-9. Our measurements also show that early- and late-type galaxies have comparable halo masses for stellar masses M_*<10^11 Msun, whereas the virial masses of early-type galaxies are higher for higher stellar masses. Finally, we determine the efficiency with which baryons have been converted into stars. Our results for early-type galaxies suggest a variation in efficiency with a minimum of ~10% for a stellar mass M_*,200=10^12 Msun. The results for the late-type galaxies are not well constrained, but do suggest a larger value. (abridged)

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑