论文标题
银河系核：银河系中心III的高角度分辨率JHK成像调查。近红外灭绝曲线波长依赖性的证据
GALACTICNUCLEUS: A high-angular-resolution JHKs imaging survey of the Galactic centre III. Evidence for wavelength dependence of the extinction curve in the near-infrared
论文作者
论文摘要
近红外（NIR）中灭绝曲线的表征是分析银河中心（GC）的结构和恒星种群的基础，其分析受到极端星际灭绝（$ a_v \ sim 30 $）的障碍，这些分析在ARC-Second尺度上各不相同。最近的研究表明，灭绝曲线的行为可能比以前假设的更为复杂，这表明灭绝曲线的变化是波长的函数。我们旨在分析具有波长，视线和绝对灭绝的灭绝指数的变化，将先前的分析扩展到了银河系最内向区域的较大区域。我们分析了整个Galacticnucleus调查，这是一种高角度分辨率（$ \ sim 0.2''$）$ JHK_S $ NIR调查，专门设计旨在以前所未有的细节观察GC。它涵盖了$ \ sim 6000 $ \，PC $^2 $的区域，包括核恒星盘，内部凸起和它们之间的过渡区域。我们采用了两种基于红色团（RC）星的独立方法来限制灭绝曲线并分析其变异取代先前的研究。我们使用了165,000多个RC恒星，并显着增加了分析区域的大小，以确认灭绝曲线随波长而变化。我们估计差异$δα= 0.21 \ pm0.07 $之间的灭绝指数，$α_{JH} = 2.44 \ pm0.05 $和$α__{hk_s} = 2.23 \ pm0.05 $。我们还得出结论，具有波长，视线或绝对灭绝的灭绝曲线没有显着变化。最后，我们计算了灭绝之间的比率，$ a_j/a_h = 1.87 \ pm0.03 $和$ a_ {h}/a_ {k_s} = 1.84 \ pm0.03 $，与Galacticnucleus Catalog的所有区域一致。
The characterisation of the extinction curve in the near infrared (NIR) is fundamental to analyse the structure and stellar population of the Galactic centre (GC), whose analysis is hampered by the extreme interstellar extinction ($A_V\sim 30$ mag) that varies on arc-second scales. Recent studies indicate that the behaviour of the extinction curve might be more complex than previously assumed, pointing towards a variation of the extinction curve as a function of wavelength. We aim at analysing the variations of the extinction index, $α$, with wavelength, line-of-sight, and absolute extinction, extending previous analysis to a larger area of the innermost regions of the Galaxy. We analysed the whole GALACTICNUCLEUS survey, a high-angular resolution ($\sim 0.2''$) $JHK_s$ NIR survey specially designed to observe the GC in unprecedented detail. It covers a region of $\sim 6000$\,pc$^2$, comprising fields in the nuclear stellar disc, the inner bulge, and the transition region between them. We applied two independent methods based on red clump (RC) stars to constrain the extinction curve and analysed its variation superseding previous studies. We used more than 165,000 RC stars and increased significantly the size of the regions analysed to confirm that the extinction curve varies with the wavelength. We estimated a difference $Δα= 0.21\pm0.07$ between the obtained extinction indices, $α_{JH}=2.44\pm0.05$ and $α_{HK_s} = 2.23\pm0.05$. We also concluded that there is no significant variation of the extinction curve with wavelength, with the line-of-sight or the absolute extinction. Finally, we computed the ratios between extinctions, $A_J/A_H = 1.87\pm0.03$ and $A_{H}/A_{K_s} = 1.84\pm0.03$, consistent with all the regions of the GALACTICNUCLEUS catalogue.
