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arXiv 1407.4470astro-ph.GAastro-ph.CO
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太多,太少,还是正好?Milky Way矮星系的数量和分布预测

Too Many, Too Few, or Just Right? The Predicted Number and Distribution of Milky Way Dwarf Galaxies

Jonathan R. Hargis, Beth Willman, Annika H. G. Peter

摘要:

通过对观测到的SDSS矮星系群的完全性修正,我们预测了DES和LSST巡天中发现的银河系矮星系的空间分布和数量。我们应用最大规模的在过去,最早的形成,最早的坠落玩具模型,一组暗物质模拟银河系/M31晕对探索本地体积模拟(ELVIS)。观测到的银河系矮星系在LSST时代的空间分布将区分最早的陷落和矮星系如何填充暗物质subhalos的其他简化模型。包括所有的玩具模型和模拟,在90%的置信度下,我们预测在300 kpc内总共有37-114 L $\gtrsim 10^3$ L $_{\odot}$侏儒和131-782 L $\lesssim 10^3$ L $_{\odot}$侏儒。这些L $\gtrsim 10^3$ L $_{\odot}$矮星的数量比以前的预测要低得多,这主要是因为我们使用了更新的探测极限,并且每个天空区域发现的SDSS矮星的数量越来越少。对于25.8 mag的有效$r_{\rm limit}$,我们预测:DES的3-13 L $\gtrsim 10^3$ L $_{\odot}$和9-99 L $\lesssim 10^3$ L $_{\odot}$侏儒,LSST的18-53 L $\gtrsim 10^3$ L $_{\odot}$和53-307 L $\lesssim 10^3$ L $_{\odot}$侏儒。这些巨大的预测范围确保了未来十年的近场兴奋与这些下一代调查。

英文摘要:

We predict the spatial distribution and number of Milky Way dwarf galaxies to be discovered in the DES and LSST surveys, by completeness correcting the observed SDSS dwarf population. We apply most massive in the past, earliest forming, and earliest infall toy models to a set of dark matter-only simulated Milky Way/M31 halo pairs from Exploring the Local Volume In Simulations (ELVIS). The observed spatial distribution of Milky Way dwarfs in the LSST-era will discriminate between the earliest infall and other simplified models for how dwarf galaxies populate dark matter subhalos. Inclusive of all toy models and simulations, at 90% confidence we predict a total of 37-114 L $\gtrsim 10^3$L$_{\odot}$ dwarfs and 131-782 L $\lesssim 10^3$L$_{\odot}$ dwarfs within 300 kpc. These numbers of L $\gtrsim 10^3$L$_{\odot}$ dwarfs are dramatically lower than previous predictions, owing primarily to our use of updated detection limits and the decreasing number of SDSS dwarfs discovered per sky area. For an effective $r_{\rm limit}$ of 25.8 mag, we predict: 3-13 L $\gtrsim 10^3$L$_{\odot}$ and 9-99 L $\lesssim 10^3$L$_{\odot}$ dwarfs for DES, and 18-53 L $\gtrsim 10^3$L$_{\odot}$ and 53-307 L $\lesssim 10^3$L$_{\odot}$ dwarfs for LSST. These enormous predicted ranges ensure a coming decade of near-field excitement with these next generation surveys.

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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