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arXiv 2008.02276astro-ph.GA
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REQUIEM-2D:基于 HST 2D 光栅光谱的空间分辨恒星种群研究

REQUIEM-2D: Spatially Resolved Stellar Populations from HST 2D Grism Spectroscopy

Mohammad Akhshik, Katherine E. Whitaker, Gabriel Brammer, Guillaume Mahler, Keren Sharon, Joel Leja, Matthew B. Bayliss, Rachel Bezanson, Michael D. Gladders, A… 展开作者

Mohammad Akhshik, Katherine E. Whitaker, Gabriel Brammer, Guillaume Mahler, Keren Sharon, Joel Leja, Matthew B. Bayliss, Rachel Bezanson, Michael D. Gladders, Allison Man, Erica J. Nelson, Jane R. Rigby, Francesca Rizzo, Sune Toft, Sarah Wellons, Christina C. Williams

AI总结:

提出贝叶斯方法 requiem2d 联合建模 HST 2d 光栅光谱与测光,测量高红移透镜星系的恒星种群与 SFH,发现 z=1.883 星系 MRG-S0851 内核具平坦年龄梯度,支持早期形成场景。

摘要:

我们提出了一种新颖的贝叶斯方法,用于联合建模高红移星系的测光和深场哈勃空间望远镜(HST)2d 光栅光谱。我们的 requiem2d 代码测量了正在进行中的 REQUIEM(解析宁静放大)星系巡天中未分辨和已分辨的恒星种群、年龄和恒星形成历史(SFH),该巡天目标为 z~2 处的强引力透镜宁静星系。我们使用来自 Illustris 宇宙学模拟的 z~2 大质量星系模拟样本测试了 requiem2d 的准确性,发现我们恢复了 SFH 和中值恒星年龄的总体趋势。我们进一步展示了 REQUIEM 星系巡天的试点研究:MRG-S0851,一个位于 z=1.883±0.001 的五重像、大质量(log M* / M_☉ = 11.02 ± 0.04)红色星系。在估计引力放大率为 μ= 5.7+0.4-0.2 的情况下,我们在 0.6 kpc 物理尺寸的箱中对恒星种群进行采样。全局质量加权中值年龄被约束为 1.8-0.2+0.3 Gyr,我们的空间分辨分析表明,在考虑尘埃和金属丰度对年龄测量的微妙影响后,MRG-S0851 在内部 3 kpc 核心区具有平坦的年龄梯度,支持早期形成场景。完整 REQUIEM-2D 样本的分析及 requiem2d 代码的测试版将在后续论文中呈现。

英文摘要:

We present a novel Bayesian methodology to jointly model photometry and deep Hubble Space Telescope (HST) 2d grism spectroscopy of high-redshift galaxies. Our requiem2d code measures both unresolved and resolved stellar populations, ages, and star-formation histories (SFHs) for the ongoing REQIUEM (REsolving QUIEscent Magnified) Galaxies Survey, which targets strong gravitationally lensed quiescent galaxies at z~2. We test the accuracy of \texttt{requiem2d} using a simulated sample of massive galaxies at z~2 from the Illustris cosmological simulation and find we recover the general trends in SFH and median stellar ages. We further present a pilot study for the REQUIEM Galaxies Survey: MRG-S0851, a quintuply-imaged, massive ($\log M_* / M_\odot = 11.02 \pm 0.04$) red galaxy at $z=1.883\pm 0.001$. With an estimated gravitational magnification of $μ= 5.7^{+0.4}_{-0.2}$, we sample the stellar populations on 0.6 kpc physical size bins. The global mass-weighted median age is constrained to be $1.8_{-0.2}^{+0.3}$ Gyr, and our spatially resolved analysis reveals that MRG-S0851 has a flat age gradient in the inner 3 kpc core after taking into account the subtle effects of dust and metallicity on age measurements, favoring an early formation scenario. The analysis for the full REQUIEM-2D sample will be presented in a forthcoming paper with a beta-release of the requiem2d code.

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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