arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1208.1763astro-ph.CO
收藏

z = 3的闭合星系对:对UV光度畸变匹配的挑战

Close Galaxy Pairs at z = 3: A Challenge to UV Luminosity Abundance Matching

Joel C. Berrier, Jeff Cooke

摘要:

我们使用一个样本的z~3莱曼Break Galerkin(LBG)检查密切对聚类统计相比,LCDM为基础的模型的结构形成。通过匹配LBG数密度和通过匹配在两个晕项区域上观察到的LBG 3-D关联函数来选择样本。我们发现,紫外线光度丰度匹配不能重现观测到的数据,但如果subhalos被选择重现观察到的LBG集群,我们能够重现观察到的LBG对分数,(NC),定义为每个星系的同伴的平均数。这个模型表明LBG的丰度比观测到的高出约5倍,这表明只有1/5的固定质量以上的晕拥有一个通过LBG选择技术检测到的具有LBG样紫外光度的星系。我们发现,在我们的过密基准模型中使用原型圆柱体半径,总的可观察到的近配对分数为23 \pm 0.6%(17.7 \pm 0.5%),在丰度匹配模型(杂质校正)中为8.3 \pm 0.5%(5.6 \pm 0.2%)。对于匹配光谱狭缝分析,我们发现Ncs = 5.1 \pm 0.2%(1.68 \pm 0.02%),在我们的基准狭缝中偶然观察到的同伴的平均数(丰度匹配),而观测到的偶然光谱紧密对的分数是4.7 \pm 1.5%,使用完整的LBG样品和7.1 \pm 2.3%。对于具有较高信噪比的子样本。我们表明,标准的方法晕分配未能重现在小尺度上的LBG的近对行为的突破。为了调和这些差异,我们建议,一个合理的小部分LBG在密切的对与较低的质量比我们的样本经验的相互作用引起的增强恒星形成,提高他们的光度足以被检测到的观测样本,但不包括在丰度匹配的模拟样本。

英文摘要:

We use a sample of z~3 Lyman Break Galaxies (LBGs) to examine close pair clustering statistics in comparison to LCDM-based models of structure formation. Samples are selected by matching the LBG number density and by matching the observed LBG 3-D correlation function of LBGs over the two-halo term region. We show that UV-luminosity abundance matching cannot reproduce the observed data, but if subhalos are chosen to reproduce the observed clustering of LBGs we are able to reproduce the observed LBG pair fraction, (Nc), defined as the average number of companions per galaxy. This model suggests an over abundance of LBGs by a factor of ~5 over those observed, suggesting that only 1 in 5 halos above a fixed mass hosts a galaxy with LBG-like UV luminosity detectable via LBG selection techniques. We find a total observable close pair fraction of 23 \pm 0.6% (17.7 \pm 0.5%) using a prototypical cylinder radius in our overdense fiducial model and 8.3 \pm 0.5% (5.6 \pm 0.2%) in an abundance matched model (impurity corrected). For the matched spectroscopic slit analysis, we find Ncs = 5.1\pm0.2% (1.68\pm0.02%), the average number of companions observed serendipitously in our for fiducial slits (abundance matched), whereas the observed fraction of serendipitous spectroscopic close pairs is 4.7\pm1.5 per cent using the full LBG sample and 7.1\pm2.3% for a subsample with higher signal-to-noise ratio. We show that the standard method of halo assignment fails to reproduce the break in the LBG close pair behavior at small scale. To reconcile these discrepancies we suggest that a plausible fraction of LBGs in close pairs with lower mass than our sample experience interaction-induced enhanced star formation that boosts their luminosity sufficiently to be detected in observational sample but are not included in the abundance matched simulation sample.

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。

↑