论文标题
NGC 628最近的恒星形成历史
The recent star formation history of NGC 628 on resolved scales
论文作者
论文摘要
恒星形成历史（SFHS）是我们对星系进化的理解不可或缺的一部分。我们可以通过比较使用不同的示踪剂计算的恒星形成速率（SFR）来研究最近的SFH，因为每个示踪剂都探测了不同的时间尺度。我们旨在校准SFR，DSFR/DT的当今变化率的代理，该速率不需要全光谱能量分布（SED）建模，并依赖于尽可能少的可观察力来保证其广泛的适用性。为了实现这一目标，我们在Cigale中创建了一组模型，并将SFR更改诊断定义为过去5和200 MYR，<SFR5>/<SFR200>的SFR的比率，由H $α$ -FUV颜色探测。我们将<sfr5>/<sfr200>应用于附近的螺旋NGC 628，并发现其恒星形成活性在最近的过去总体上正在下降，但是，由于螺旋臂保持了更高的活性。观察到螺旋臂结构的影响比<sfr5>/<sfr200>更强，而不是在星形构造效率上（sfe $ _ \ text {h $ _2 $} $）。另外，增加的磁盘压力倾向于增加近期的恒星形成，因此<sfr5>/<SFR200>。我们得出的结论是，<sfr5>/<sfr200>对分子气体含量，螺旋臂结构和磁盘压力敏感。 <sfr5>/<sfr200>指示器是通用的，可用于重建任何恒星形成的星系的SFH，而H $α$，FUV以及中等或FAR-IR光度法都可以使用，而无需详细建模。
Star formation histories (SFHs) are integral to our understanding of galaxy evolution. We can study recent SFHs by comparing the star formation rate (SFR) calculated using different tracers, as each probes a different timescale. We aim to calibrate a proxy for the present-day rate of change in SFR, dSFR/dt, which does not require full spectral energy distribution (SED) modeling and depends on as few observables as possible, to guarantee its broad applicability. To achieve this, we create a set of models in CIGALE and define an SFR change diagnostic as the ratio of the SFR averaged over the past 5 and 200 Myr, <SFR5>/<SFR200>, probed by the H$α$-FUV colour. We apply <SFR5>/<SFR200> to the nearby spiral NGC 628 and find that its star formation activity has overall been declining in the recent past, with the spiral arms, however, maintaining a higher level of activity. The impact of the spiral arm structure is observed to be stronger on <SFR5>/<SFR200> than on the star formation efficiency (SFE$_\text{H$_2$}$). In addition, increasing disk pressure tends to increase recent star formation, and consequently <SFR5>/<SFR200>. We conclude that <SFR5>/<SFR200> is sensitive to the molecular gas content, spiral arm structure, and disk pressure. The <SFR5>/<SFR200> indicator is general and can be used to reconstruct the recent SFH of any star-forming galaxy for which H$α$, FUV, and either mid- or far-IR photometry is available, without the need of detailed modeling.
