论文标题

富含金属银河系中恒星,中性和电离气体金属度的首次共同空间比较:M83

First Co-spatial Comparison of Stellar, Neutral-, and Ionized-gas Metallicities in a metal-rich galaxy: M83

论文作者

Hernandez, Svea, Aloisi, Alessandra, James, Bethan L., Kumari, Nimisha, Berg, Danielle, Adamo, Angela, Blair, William P., Faucher-Giguère, Claude-André, Fox, Andrew J., Gurvich, Alexander B., Hafen, Zachary, Heckman, Timothy M., Lebouteiller, Vianney, Long, Knox S., Skillman, Evan D., Tumlinson, Jason, Whitmore, Bradley C.

论文摘要

我们对富含金属的螺旋星系M83中恒星,中性气和电离气体成分的金属性进行比较分析。我们分析了使用哈勃太空望远镜(HST),大双筒望远镜(LBT)和非常大的望远镜(VLT)进行的光谱观测。从此螺旋星系的核区域的HI柱密度中观察到,我们检测到HI气体的明显耗竭。 We find column densities of log[$N$(HI) cm$^{-2}$] $<$ 20.0 at galactocentric distances of $<$ 0.18 kpc, in contrast to column densities of log[$N$(HI) cm$^{-2}$] $\sim$ 21.0 in the galactic disk, a trend observed in other nearby spiral galaxies.对于电离气体,我们测量的金属性梯度为$ - 0.03 $ \ $ 0.01 $ 0.01 dex kpc $^{ - 1} $,可与附近49个附近星形星系的本地基准的金属梯度相媲美,$ 0.026 $ 0.026 $ 0.002 $ 0.002 dex dex kpc kpc $ 0.002 $ 0.002 $^$^ - 1}。我们对多相气体和恒星种群的共同空间金属性比较在星系核之外表现出了极好的一致性,暗示了一个场景,在这种情况下,在星形群体中,新合成的金属的混合混合的寿命比他们的寿命更长($ \ sim sim $ 10 myr)。最后,我们的工作表明,在研究星形星系中中性气体成分的金属性梯度时必须谨慎,因为这可以强烈偏见,因为这些环境可以由分子气体主导。在这些区域中,典型的金属性示踪剂可以提供不准确的丰度,因为它们可能同时追踪中性和分子气体成分。

We carry out a comparative analysis of the metallicities from the stellar, neutral-gas, and ionized-gas components in the metal-rich spiral galaxy M83. We analyze spectroscopic observations taken with the Hubble Space Telescope (HST), the Large Binocular Telescope (LBT) and the Very Large Telescope (VLT). We detect a clear depletion of the HI gas, as observed from the HI column densities in the nuclear region of this spiral galaxy. We find column densities of log[$N$(HI) cm$^{-2}$] $<$ 20.0 at galactocentric distances of $<$ 0.18 kpc, in contrast to column densities of log[$N$(HI) cm$^{-2}$] $\sim$ 21.0 in the galactic disk, a trend observed in other nearby spiral galaxies. We measure a metallicity gradient of $-$0.03 $\pm$ 0.01 dex kpc$^{-1}$ for the ionized gas, comparable to the metallicity gradient of a local benchmark of 49 nearby star-forming galaxies of $-$0.026 $\pm$ 0.002 dex kpc$^{-1}$. Our co-spatial metallicity comparison of the multi-phase gas and stellar populations shows excellent agreement outside of the nucleus of the galaxy hinting at a scenario where the mixing of newly synthesized metals from the most massive stars in the star clusters takes longer than their lifetimes ($\sim$10 Myr). Finally, our work shows that caution must be taken when studying the metallicity gradient of the neutral-gas component in star-forming galaxies, since this can be strongly biased, as these environments can be dominated by molecular gas. In these regions the typical metallicity tracers can provide inaccurate abundances as they may trace both the neutral- and molecular-gas components.

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