The survey of planetary nebulae in Andromeda (M31) - IV. Radial oxygen and argon abundance gradients of the thin and thicker disc
The survey of planetary nebulae in Andromeda (M31) - IV. Radial oxygen and argon abundance gradients of the thin and thicker disc
复制标题
仙女座行星状星云 (M31) 的调查 - IV。
DOI：
10.1093/mnras/stac2703
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发表时间：
2022
影响因子：
4.8
通讯作者：
Bhattacharya S
中科院分区：
文献类型：
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作者：
Bhattacharya S
我们获得了仙女座（m31）圆盘PNe的有限等样本，通过直接检测[Oiii] 4363 Å线估计了化学丰度。这导致205 PNe和200 PNe分别具有氧和氩的丰度。我们发现m31星盘PNe的高灭星和低灭星在氩和氧的丰度分布上有统计学上的差异。2−30 kpc的辐射范围,老low-extinction阀瓣PNe稍微积极径向氧气缺乏金属的平均丰度梯度(0.006±0.003敏捷kpc−1)和略-氩(−0.005±0.003敏捷kpc−1),而年轻high-extinction盘PNe与陡峭的径向平均富含金属丰度梯度对氧气(−0.013±0.006敏捷kpc−1)和氩(−0.018±0.006敏捷kpc−1),类似于M 31 Hiiregions梯度计算。m31的盘丰度梯度与主要合并模拟计算的值一致，大多数低消光星云星云是较厚盘中较老的合并前盘星，而大多数高消光星云星云星云是在合并事件期间和之后形成的薄盘中较年轻的恒星。由于主要的合并，m31较厚的盘的化学丰度已经径向均匀化。考虑到盘的尺度长度，m31厚盘的正径向氧丰度梯度与MW厚盘的负径向氧丰度梯度形成鲜明对比。然而，MW和m31的薄圆盘具有非常相似的负氧丰度梯度。
We obtain a magnitude-limited sample of Andromeda (M 31) disc PNe with chemical abundance estimated through the direct detection of the [Oiii] 4363 Å line. This leads to 205 and 200 PNe with oxygen and argon abundances, respectively. We find that high- and low-extinction M 31 disc PNe have statistically distinct argon and oxygen abundance distributions. In the radial range of 2−30 kpc, the older low-extinction disc PNe are metal-poorer on average with a slightly positive radial oxygen abundance gradient (0.006 ± 0.003 dex kpc−1) and slightly negative for argon (−0.005 ± 0.003 dex kpc−1), while the younger high-extinction disc PNe are metal-richer on average with steeper radial abundance gradients for both oxygen (−0.013 ± 0.006 dex kpc−1) and argon (−0.018 ± 0.006 dex kpc−1), similar to the gradients computed for the M 31 Hiiregions. The M 31 disc abundance gradients are consistent with values computed from major merger simulations, with the majority of the low-extinction PNe being the older pre-merger disc stars in the thicker disc, and the majority of the high-extinction PNe being younger stars in the thin disc, formed during and after the merger event. The chemical abundance of the M 31 thicker disc has been radially homogenized because of the major merger. Accounting for disc scale lengths, the positive radial oxygen abundance gradient of the M 31 thicker disc is in sharp contrast to the negative one of the MW thick disc. However, the thin discs of the MW and M 31 have remarkably similar negative oxygen abundance gradients.