Deep Narrowband Photometry of the M101 Group: Strong-line Abundances of 720 H ii Regions
Deep Narrowband Photometry of the M101 Group: Strong-line Abundances of 720 H ii Regions
复制标题
M101星系群的深窄带光度测定：720h ii区的强线丰度
DOI：
10.3847/1538-4357/aca27a
复制
发表时间：
2022-11
期刊：
影响因子：
--
通讯作者：
Ray Garner;J. C. Mihos;P. Harding;A. Watkins;Stacy S. McGaugh Case Western Reserve University;U. Hertfordshire
中科院分区：
文献类型：
--
作者：
Ray Garner;J. C. Mihos;P. Harding;A. Watkins;Stacy S. McGaugh Case Western Reserve University;U. Hertfordshire
我们展示了附近螺旋星系 M101 及其卫星的深部窄带成像，以分析其 H ii 区域的氧丰度。利用凯斯西储大学的Burrell Schmidt望远镜，我们首次添加了M101群的窄带数据集，其中包括Hα、Hβ和[O iii]发射线以及蓝色[O ii] λ3727发射线。这样可以完全覆盖整个 M101 群的氧丰度。我们使用强线比 R 23 来估计样品中 H ii 区域的氧丰度，利用三种不同的校准技术来提供氧丰度的基线估计。这导致 M101 产生约 650 个 H ii 区域，NGC 5477 产生 10 个 H ii 区域，NGC 5474 产生约 60 个 H ii 区域，这是该组迄今为止最大的样本。 M101表现出很强的丰度梯度，而卫星星系则表现出很小或没有梯度。有一些证据表明 M101 中的梯度在 R ∼ 14 kpc 之外变得平坦。此外，M101 显示出向西和西南部方位丰度变化的迹象。 M101 的径向和方位丰度变化很可能是由于它与 300 Myr 前最大的卫星 NGC 5474 的相互作用以及内部动力效应（例如共转）来解释的。
We present deep, narrowband imaging of the nearby spiral galaxy M101 and its satellites to analyze the oxygen abundances of their H ii regions. Using Case Western Reserve University’s Burrell Schmidt telescope, we add to the narrowband data set of the M101 Group, consisting of Hα, Hβ, and [O iii] emission lines and the blue [O ii] λ3727 emission line for the first time. This allows for complete spatial coverage of the oxygen abundance of the entire M101 Group. We used the strong-line ratio R 23 to estimate oxygen abundances for the H ii regions in our sample, utilizing three different calibration techniques to provide a baseline estimate of the oxygen abundances. This results in ∼650 H ii regions for M101, 10 H ii regions for NGC 5477, and ∼60 H ii regions for NGC 5474, the largest sample for this Group to date. M101 shows a strong abundance gradient, while the satellite galaxies present little or no gradient. There is some evidence for a flattening of the gradient in M101 beyond R ∼ 14 kpc. Additionally, M101 shows signs of azimuthal abundance variations to the west and southwest. The radial and azimuthal abundance variations in M101 are likely explained by an interaction it had with its most massive satellite, NGC 5474, ∼300 Myr ago combined with internal dynamical effects such as corotation.