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arXiv 2405.04166astro-ph.GA
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SDSS-MaNGA中恒星形成椭圆星系的结构与运动学

Structure and Kinematics of Star-forming Elliptical Galaxies in SDSS-MaNGA

Pralay Biswas, Yogesh Wadadekar

AI总结:

本研究利用SDSS-MaNGA数据发现了59个罕见的恒星形成椭圆星系,通过对比分析表明它们通过并合或相互作用获得贫气气体并形成新恒星,并基于结构参数将其细分为四类,指出Hubble图需修订以完整反映星系演化过程。

摘要:

利用空间分辨光谱,我们研究了椭圆星系中恒星的特征及不同的形成模式。我们在SDSS-MaNGA中识别出了一个由59个恒星形成椭圆星系(SF-E)组成的罕见星系群,作为我们的主样本。为了识别这些罕见的恒星形成椭圆星系,我们将包含恒星种群合成模型输出的GSWLC-A2、来自深度学习目录的形态学结果,以及来自MaNGA Pipe3D增值目录的分辨和积分属性相结合。我们还构建了两个控制样本:恒星形成旋涡星系(SF-Sps;2419个星系)和熄灭椭圆星系(Q-Es;684个星系),以便与我们的SF-Es主样本进行比较。SF-Es的H$α$发射线通量与旋涡星系相似。D4000光谱指数表明,SF-Es具有年轻和年老恒星种群的混合。SF-Es的质量加权恒星年龄和金属丰度低于Q-Es,且主样本中67%的恒星和气体速度图显示出运动学扰动的迹象。所有这些都表明,SF-Es通过最近的并合或与其他星系的相互作用获得了贫气气体,并正在形成新一代恒星。此外,我们根据核球与总光度比$(B/T)$和自旋参数$λ_{re}$将SF-Es主样本细分为四类。这四类具有各自独特的演化历史和形成模式。基于这些结果,我们建议Hubble图不能准确捕捉星系演化过程,我们需要一个修订后的形态学图(如梳状形态图)来获得星系演化过程的完整图景。

英文摘要:

Using 'spatially' resolved spectroscopy, we investigated the characteristics and different modes of formation of stars in elliptical galaxies. We identified an unusual population of 59 star-forming elliptical (SF-E) galaxies in SDSS-MaNGA, our primary sample. To identify these rare star-forming ellipticals, we combined GSWLC-A2 containing outputs of stellar population synthesis models with morphological results from the deep-learning catalog and resolved and integrated properties from the MaNGA Pipe3D value-added catalog. We have also constructed two control samples of star-forming spirals (SF-Sps; 2419 galaxies) and quenched ellipticals (Q-Es; 684 galaxies) to compare with our primary sample of SF-Es. H$α$ emission line flux of SF-Es is similar to spiral galaxies. The D4000 spectral index indicates that SF-Es have a mixture of old and young stellar populations. Mass-weighted stellar age and metallicity for the SF-Es are lower than the Q-Es and 67\% of stellar- and gas- velocity maps of the primary sample show signs of kinematic disturbance. All of these indicate that SF-Es have acquired metal-poor gas through recent mergers or interactions with other galaxies and are forming a new generation of stars. Further, we subdivide our primary sample of SF-Es into four classes based on their bulge to total luminosity ratio $(B/T)$ and spin parameter $λ_{re}$. These four classes have their distinct evolutionary history and modes of formation. Based on these results, we suggest that the Hubble diagram does not accurately capture galaxy evolution processes, and we need a revised morphology diagram like the comb morphology diagram to get a complete picture of the galaxy evolution processes.

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