New Constraints on the Origin of Surface Brightness Profile Breaks of Disk Galaxies from MaNGA
New Constraints on the Origin of Surface Brightness Profile Breaks of Disk Galaxies from MaNGA
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DOI：
10.3847/1538-4357/ab98fd
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发表时间：
2020-06
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通讯作者：
Yimeng Tang;Qian Chen;Hong-Xin Zhang;Zesen Lin;Guangwen Chen;Yulong Gao;Zhixiong Liang;Haiyang Liu;X. Kong
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文献类型：
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作者：
Yimeng Tang;Qian Chen;Hong-Xin Zhang;Zesen Lin;Guangwen Chen;Yulong Gao;Zhixiong Liang;Haiyang Liu;X. Kong
为了探索在附近盘星系中广泛观测到的表面亮度轮廓(SBP)破缺的起源，我们对阿帕奇点天文台测绘附近星系光谱调查中选择的635个盘星系的恒星群分布进行了比较研究。我们将我们的星系分为单指数(Ti)、下弯(Tii)和上弯(TiII)SBP类型，并推导出它们的自旋参数和年龄/金属丰度敏感光谱特征的径向分布。大多数TiI(TiII)星系具有向下弯曲(上弯曲)的恒星形成率(SFR)径向轮廓，这意味着SFR强度的径向突变有助于TiI和TiII爆发的形成。然而，我们的星系和模拟结果之间的比较表明，恒星迁移在削弱向下弯曲的Σ⋆轮廓断裂方面发挥了重要作用。虽然TiI星系的SBPS破裂强度与年龄/金属丰度敏感的光谱特征之间存在相关性，但对于TiII星系却没有发现这种相关性，这表明恒星迁移可能不是形成TiII星系破裂的主要原因，TiII星系的Σ⋆破裂强度和SBPS之间的良好对应也证明了这一点。我们没有发现证据表明星系自转是形成不同SBP类型的相关参数，我们也没有发现不同SBP类型星系的不对称性之间的显著差异，这表明最近过去的环境扰动或卫星吸积不会显著影响破裂的形成。通过将我们的样本分为早期和晚期两种形态类型，我们发现不同SBP类型的星系遵循几乎相同的紧密恒星质量关系，这使得仅靠恒星迁移就可以将SBP类型从TiI转变为TiI进而转变为TiII的假设变得不太可能。
In an effort to probe the origin of surface brightness profile (SBP) breaks widely observed in nearby disk galaxies, we carry out a comparative study of stellar population profiles of 635 disk galaxies selected from the Mapping Nearby Galaxies at Apache Point Observatory spectroscopic survey. We classify our galaxies into single exponential (Ti), down-bending (Tii), and up-bending (Tiii) SBP types and derive their spin parameters and radial profiles of age/metallicity-sensitive spectral features. Most Tii (Tiii) galaxies have down-bending (up-bending) star formation rate (SFR) radial profiles, implying that abrupt radial changes of SFR intensities contribute to the formation of both Tii and Tiii breaks. Nevertheless, a comparison between our galaxies and simulations suggests that stellar migration plays a significant role in weakening down-bending Σ⋆ profile breaks. While there is a correlation between the break strengths of SBPs and age/metallicity-sensitive spectral features for Tii galaxies, no such correlation is found for Tiii galaxies, indicating that stellar migration may not play a major role in shaping Tiii breaks, as is also evidenced by a good correspondence between the break strengths of Σ⋆ and SBPs of Tiii galaxies. We do not find evidence for galaxy spin being a relevant parameter for forming different SBP types, nor do we find significant differences between the asymmetries of galaxies with different SBP types, suggesting that environmental disturbances or satellite accretion in the recent past do not significantly influence the break formation. By dividing our sample into early and late morphological types, we find that galaxies with different SBP types follow nearly the same tight stellar mass– relation, which makes the hypothesis that stellar migration alone can transform SBP types from Tii to Ti and then to Tiii highly unlikely.