The EDGE-CALIFA survey: The role of spiral arms and bars in driving central molecular gas concentrations
The EDGE-CALIFA survey: The role of spiral arms and bars in driving central molecular gas concentrations
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EDGE-CALIFA 调查：旋臂和棒在驱动中心分子气体浓度中的作用
DOI：
10.1051/0004-6361/202244306
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发表时间：
2022
影响因子：
6.5
通讯作者：
Vogel, Stuart N.
中科院分区：
文献类型：
--
作者：
Yu, Si-Yue;Kalinova, Veselina;Colombo, Dario;Bolatto, Alberto D.;Wong, Tony;Levy, Rebecca C.;Villanueva, Vicente;Sánchez, Sebastián F.;Ho, Luis C.;Vogel, Stuart N.
非轴对称结构产生的冲击波和扭矩，如旋臂和棒状物，可能会将气体输送到星系中心区域。我们利用EDGE-CALIFA调查中选取的57个盘状星系的样本，研究了中心∼-2KPC的CO光度(Cco)、分子气体(CmoL)浓度和恒星形成率(Csfr)与非轴对称盘状结构强度的关系，从而验证了这一假说。Cmol值是使用CO-to-H_2转换因子计算的，该系数随金属丰度和恒星表面密度的增加而减小。我们发现Cmolis系统地比CCO低0.22dex。我们证实，高C摩尔和强的非轴对称盘状结构在条状星系中比在非条状星系中更常见。然而，我们发现旋臂也增加了CmoL。我们发现Cmol值与非轴对称结构的强度之间有很好的相关性(这可能是由于杆、螺旋臂或两者兼而有之)。这表明，条状星云和螺旋星云越强，银河系向中心输送冷气的效率就越高。尽管子样本量很小，但与盘结构相似的非活动星系相比，四个Seyfert星系的Cmol值并没有显著降低，这意味着Seyferts中的活动星系核反馈可能不会显著影响中心∼2KPC中的分子气体分布。我们发现CSFR与Cmolin密切相关，无论是无障碍星系还是有障碍星系。同样，在具有强大盘状结构的星系中也发现了升高的CSFR。我们的结果表明，无论是螺旋状还是条状的盘状结构，都可以将气体输送到中心区域，更高的流入速率对应于更强的结构，从而促进中央恒星的形成。因此，螺旋和棒状星系在盘状星系的长期演化中都扮演着重要的角色。
Shocks and torques produced by non-axisymmetric structures such as spiral arms and bars may transport gas to galaxy central regions. We test this hypothesis by studying the dependence of the concentration of CO luminosity (CCO) and molecular gas (Cmol) and the star formation rate (CSFR) in the central ∼2 kpc on the strength of non-axisymmetric disk structure using a sample of 57 disk galaxies selected from the EDGE-CALIFA survey. TheCmolis calculated using a CO-to-H2conversion factor that decreases with higher metallicity and higher stellar surface density. We find thatCmolis systematically 0.22 dex lower thanCCO. We confirm that highCmoland strong non-axisymmetric disk structure are more common in barred galaxies than in unbarred galaxies. However, we find that spiral arms also increaseCmol. We show that there is a good correlation betweenCmoland the strength of non-axisymmetric structure (which can be due to a bar, spiral arms, or both). This suggests that the stronger the bars and spirals, the more efficient the galaxy is at transporting cold gas to its center. Despite the small subsample size, theCmolof the four Seyferts are not significantly reduced compared to inactive galaxies of similar disk structure, implying that the active galactic nucleus feedback in Seyferts may not notably affect the molecular gas distribution in the central ∼2 kpc. We find thatCSFRtightly correlates withCmolin both unbarred and barred galaxies. Likewise, elevatedCSFRis found in galaxies with strong disk structure. Our results suggest that the disk structure, either spirals or bars, can transport gas to the central regions, with higher inflow rates corresponding to stronger structure, and consequently boost central star formation. Both spirals and bars play, therefore, an essential role in the secular evolution of disk galaxies.