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arXiv 1806.01307astro-ph.GA
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在千度巡天中光谱证实的超紧凑大质量星系的第一个样本

The first sample of spectroscopically confirmed ultra-compact massive galaxies in the Kilo Degree Survey

C. Tortora, N. R. Napolitano, M. Spavone, F. La Barbera, G. D'Ago, C. Spiniello, K. H. Kuijken, N. Roy, M. A. Raj, S. Cavuoti, M. Brescia, G. Longo, V. Pota, C.… 展开作者

C. Tortora, N. R. Napolitano, M. Spavone, F. La Barbera, G. D'Ago, C. Spiniello, K. H. Kuijken, N. Roy, M. A. Raj, S. Cavuoti, M. Brescia, G. Longo, V. Pota, C. E. Petrillo, M. Radovich, F. Getman, L. V. E. Koopmans, I. Trujillo, G. Verdoes Kleijn, M. Capaccioli, A. Grado, G. Covone, D. Scognamiglio, C. Blake, K. Glazebrook, S. Joudaki, C. Lidman, C. Wolf

摘要:

我们目前正在进行的调查,使用千度巡天(KiDS)的VLT巡天望远镜(VST)提供一个人口普查的超紧凑的大质量星系(UCMG),定义为星系的恒星质量$M_{\rm \star} > 8 \times 10^{10} \rm M_{\odot}$和有效半径$R_{\rm e} < 1.5\,\rm kpc$。UCMG预计经历了很少的合并事件,为宇宙中最大星系的吸积历史提供了独特的视角。在近330平方度的有效天空区域内,我们从KiDS多色图像中选择UCMG候选者,这些图像提供了高质量的结构参数,光度红移和恒星质量。我们在$z < 0.5$的$\sim 1000$光度选择的UCMG样本代表了迄今为止在最大天空区域组装的最大UCMG候选样本。在本文中,我们提出了第一次努力,以获得他们的红移使用不同的设施,从第一个结果与红移$z < 0.5$,在NTT和TNG望远镜获得的28个候选人。我们确认,作为真正的UCMG,28个候选者中有19个具有新的红移。另外46个UCMG候选者被证实与文献光谱红移(35在$z < 0.5$),使光谱确认的低z UCMG的最终累积样本54个星系,这是最大的样本在红移低于$0.5$。我们使用这些光谱红移来量化测光选择中的系统误差,并使用这些来校正UCMG数计数。最后,我们将结果与独立的数据集和模拟进行比较。

英文摘要:

We present results from an ongoing investigation using the Kilo Degree Survey (KiDS) on the VLT Survey Telescope (VST) to provide a census of ultra-compact massive galaxies (UCMGs), defined as galaxies with stellar masses $M_{\rm \star} > 8 \times 10^{10} \rm M_{\odot}$ and effective radii $R_{\rm e} < 1.5\,\rm kpc$. UCMGs, which are expected to have undergone very few merger events, provide a unique view on the accretion history of the most massive galaxies in the Universe. Over an effective sky area of nearly 330 square degrees, we select UCMG candidates from KiDS multi-colour images, which provide high quality structural parameters, photometric redshifts and stellar masses. Our sample of $\sim 1000$ photometrically selected UCMGs at $z < 0.5$ represents the largest sample of UCMG candidates assembled to date over the largest sky area. In this paper we present the first effort to obtain their redshifts using different facilities, starting with first results for 28 candidates with redshifts $z < 0.5$, obtained at NTT and TNG telescopes. We confirmed, as bona fide UCMGs, 19 out of the 28 candidates with new redshifts. A further 46 UCMG candidates are confirmed with literature spectroscopic redshifts (35 at $z < 0.5$), bringing the final cumulative sample of spectroscopically-confirmed lower-z UCMGs to 54 galaxies, which is the largest sample at redshifts below $0.5$. We use these spectroscopic redshifts to quantify systematic errors in our photometric selection, and use these to correct our UCMG number counts. We finally compare the results to independent datasets and simulations.

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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