论文标题
在自愿计算的IGIMF理论中，超生物矮星系的化学演变
Chemical evolution of ultra-faint dwarf galaxies in the self-consistently calculated IGIMF theory
论文作者
论文摘要
银河系的金属性和恒星形成速率（SFR）的星系范围的恒星初始质量功能（GWIMF）可以通过综合银河IMF（IGIMF）理论来计算。 Lacchin等。 （2019年）首次应用IGIMF理论来研究超生物矮人（UFD）卫星星系的化学演化，并且未能再现数据。在这里，我们发现IGIMF理论自然与数据一致。我们应用在每个时间步中计算的时间不断发展的GWIMF。根据GWIMF，IA型超新星型爆炸的数量是重归其的。计算了BoötesI的化学演化，这是最佳观察到的UFD之一。我们的计算表明，Boötesi的底光和顶浅的Gwimf具有与其他矮人相同的气体消耗时间尺度，但在形成后淬火量为0.1 Gyr，与独立估计相一致，与独立的估计和类似的龙蝇44。 （2019年），在我们的结论之间产生差异。此外，还对不确定性进行了详细讨论，以解决化学演化模型的结果如何取决于应用的假设。这项研究证明了IGIMF理论在理解极端环境中恒星形成方面的力量，并表明UDF是限制低质量恒星IMF变化的有前途的途径。
The galaxy-wide stellar initial mass function (gwIMF) of a galaxy in dependence of its metallicity and star formation rate (SFR) can be calculated by the integrated galactic IMF (IGIMF) theory. Lacchin et al. (2019) apply the IGIMF theory for the first time to study the chemical evolution of the ultra-faint dwarf (UFD) satellite galaxies and failed to reproduce the data. Here, we find that the IGIMF theory is naturally consistent with the data. We apply the time-evolving gwIMF calculated at each timestep. The number of type Ia supernova explosions per unit stellar mass formed is renormalised according to the gwIMF. The chemical evolution of Boötes I, one of the best observed UFD, is calculated. Our calculation suggests a mildly bottom-light and top-light gwIMF for Boötes I, and that this UFD has the same gas-consumption timescale as other dwarfs but was quenched about 0.1 Gyr after formation, being consistent with independent estimations and similar to Dragonfly 44. The recovered best fitting input parameters in this work are not covered in the work of Lacchin et al. (2019), creating the discrepancy between our conclusions. In addition, a detailed discussion of uncertainties is presented addressing how the results of chemical evolution models depend on applied assumptions. This study demonstrates the power of the IGIMF theory in understanding the star-formation in extreme environments and shows that UDFs are a promising pathway to constrain the variation of the low-mass stellar IMF.
