We characterized the kinematics, morphology, and stellar population (SP) properties of a sample of massive compact quiescent galaxies (MCGs, $10\, \lesssim \, \log M_\star$/M$_\odot \, \lesssim \, 11$ and re ∼ 1–3 kpc) in the MaNGA Survey, with the goal of constraining their formation, assembly history, and assessing their relation with non-compact quiescent galaxies. We compared their properties with those of a control sample of median-sized quiescent galaxies (re ∼ 4–8 kpc) with similar effective velocity dispersions. MCGs have elevated rotational support, as evidenced by a strong anticorrelation between the Gauss–Hermite moment h3 and V/σ. In contrast, 30${{\ \rm per\ cent}}$ of control sample galaxies (CSGs) are slow rotators, and fast-rotating CSGs generally show a weak h3–V/σ anticorrelation. MCGs and CSGs have similar ages, but MCGs are more metal-rich and α-enhanced. Both MCGs and CSGs have shallow negative metallicity gradients and flat [α/Fe] gradients. On average, MCGs and CSGs have flat age gradients, but CSGs have a significantly larger dispersion of gradient values. The kinematics and SP properties of MCGs suggest that they experienced highly dissipative gas-rich events, such as mergers, followed by an intense, short, and centrally concentrated burst of star formation, between 4 and 10 Gyr ago (z ∼ 0.4–2), and had a quiet accretion history since then. This sequence of events might be analogous to, although less extreme than, the compaction events that formed compact quiescent galaxies at z ∼ 2. The small sizes of MCGs, and the high efficiency and short duration of their last star formation episode suggest that they are descendants of compact post-starburst galaxies.

中文翻译：

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MaNGA中大质量致密星系的令人费解的起源

我们对大质量致密静止星系样本（MCGs, $10\, \lesssim \, \log M_\star$/M$_\odot \, \lesssim \, 11$ 和 re ∼ 1-3 kpc) 在 MaNGA 调查中，目的是限制它们的形成、组装历史，并评估它们与非致密静止星系的关系。我们将它们的性质与具有相似有效速度色散的中等大小静止星系（re ∼ 4-8 kpc）的对照样本进行了比较。高斯-厄米特矩 h3 和 V/σ 之间的强反相关证明 MCG 具有较高的旋转支持。相比之下，30${{\ \rm per\ cent}}$ 的对照样本星系 (CSG) 是慢速自转星，而快速自转的 CSG 通常表现出较弱的 h3-V/σ 反相关。MCG 和 CSG 的年龄相似，但 MCG 更富含金属且 α 增强。MCG 和 CSG 都具有浅的负金属丰度梯度和平坦的 [α/Fe] 梯度。平均而言，MCG 和 CSG 具有平坦的年龄梯度，但 CSG 具有明显更大的梯度值离散度。MCG 的运动学和 SP 特性表明，它们经历了高度耗散的富含气体事件，例如合并，随后是 4 到 10 Gyr 前（z ∼ 0.4-2）之间的强烈、短暂和中心集中的恒星形成爆发，并且从那以后有一段安静的吸积历史。这一系列事件可能类似于，尽管没有那么极端，在 z ∼ 2 处形成致密静止星系的压实事件。MCG 的小尺寸，