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arXiv 2408.14560astro-ph.CO
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利用星系群改进超新星宇宙学红移的测定

Improving the Determination of Supernova Cosmological Redshifts by Using Galaxy Groups

Erik R. Peterson, Bastien Carreres, Anthony Carr, Daniel Scolnic, Ava Bailey, Tamara M. Davis, Dillon Brout, Cullan Howlett, David O. Jones, Adam G. Riess, Khal… 展开作者

Erik R. Peterson, Bastien Carreres, Anthony Carr, Daniel Scolnic, Ava Bailey, Tamara M. Davis, Dillon Brout, Cullan Howlett, David O. Jones, Adam G. Riess, Khaled Said, Georgie Taylor

AI总结:

本文利用N体模拟和英澳望远镜光谱数据,证明通过星系群平均红移可将SN Ia宿主星系红移精度提高约135-145 km/s,并提出针对ZTF和LSST低红移样本的星系群证认是一种高性价比的宇宙学约束增强策略。

摘要:

在Ia型超新星(SNe Ia)哈勃图的低红移端($z<0.05$),本动速度对哈勃残差弥散的贡献与SN Ia光变曲线标准化的局限性所导致的贡献大小相当。改进SN宿主星系红移测量的一种方法是利用星系群的平均红移,从而有效地对小尺度/星系团内本动速度进行平均。一个限制因素是SN宿主星系位于星系群中的比例,此前利用(相对不完整的)星等限制星系表发现该比例为30%。本文首次对N体模拟进行分析以预测这一比例,发现约73%的宿主星系应有关联星系群,且星系群平均可将红移精度提高约135 km s$^{-1}$(在$z=0.025$处约为0.04 mag)。此外,利用英澳望远镜的光谱数据,我们展示了首个试点项目的结果,以评估23个此前未关联的SN Ia宿主是否属于星系群。我们发现这些候选宿主中有91%可与星系群关联,在给定样本量下与模拟预测一致。结合Pantheon+中先前已指定的SN宿主星系,我们证明哈勃残差弥散的改善相当于145 km s$^{-1}$,也与模拟一致。对于来自例如ZTF和LSST的新的和即将到来的低$z$样本,一个单独的识别SN宿主星系群的后续观测项目是增强其约束能力的一种极具成本效益的方式。

英文摘要:

At the low-redshift end ($z<0.05$) of the Hubble diagram with Type Ia Supernovae (SNe Ia), the contribution to Hubble residual scatter from peculiar velocities is of similar size to that due to the limitations of the standardization of the SN Ia light curves. A way to improve the redshift measurement of the SN host galaxy is to utilize the average redshift of the galaxy group, effectively averaging over small-scale/intracluster peculiar velocities. One limiting factor is the fraction of SN host galaxies in galaxy groups, previously found to be 30% using (relatively incomplete) magnitude-limited galaxy catalogs. Here, we do the first analysis of N-body simulations to predict this fraction, finding $\sim$73% should have associated groups and group averaging should improve redshift precision by $\sim$135 km s$^{-1}$ ($\sim$0.04 mag at $z=0.025$). Furthermore, using spectroscopic data from the Anglo-Australian Telescope, we present results from the first pilot program to evaluate whether or not 23 previously unassociated SN Ia hosts belong in groups. We find that 91% of these candidates can be associated with groups, consistent with predictions from simulations given the sample size. Combining with previously assigned SN host galaxies in Pantheon+, we demonstrate improvement in Hubble residual scatter equivalent to 145 km s$^{-1}$, also consistent with simulations. For new and upcoming low-$z$ samples from, for example, ZTF and LSST, a separate follow-up program identifying galaxy groups of SN hosts is a highly cost-effective way to enhance their constraining power.

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。

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