论文标题
NGC 3311中心的灰尘和星形形成
Dust and star formation in the centre of NGC 3311
论文作者
论文摘要
NGC 3311是Hydra I Galaxy群集的中央星系。它具有热星介质，并设有带有发射线的中央防尘车道。这些尘埃道在椭圆星系中很常见，但是NGC 3311的情况对于尘埃生命的问题和中央部分中凉气的作用可能特别有趣。我们旨在使用档案HST图像和缪斯数据数据来研究NGC 3311的中央尘埃结构。我们使用工具pyparadise对恒星种群进行建模并提取排放线。 HST/ACS颜色图揭示了已知的灰尘结构，但也揭示了蓝色斑点，这是线条发射强的地方。尘土飞扬的“迷你杰特”从中心散发出来。排放线气体的分布几乎完全匹配尘埃轮廓。接近最明亮的HALPHA发射，比率[NII]/HALPHA类似于HII区的比率；在外部，[NII]变得更强壮，并且类似于衬里样光谱。气体运动学与旋转盘的气体一致。最强线排放的多普勒移动表明最高的恒星形成活性区域，非常适合圆盘对称性。金属性是超极的。中性气体的存在由恒星Nai D吸收系的拟合残差表示，我们将其解释为星际吸收。我们估计中性气体的质量为X射线质量的顺序。动态质量渗透了中等年龄的出色种群，其球状簇已经被鉴定出来。我们的发现可以在恒星形成的情况下通过冷气积聚到预先存在的气体/防尘盘或环上触发的情况。然后，新生产的灰尘有助于灰尘的寿命。
NGC 3311 is the central galaxy of the Hydra I galaxy cluster. It has a hot interstellar medium and hosts a central dust lane with emission lines. These dust lanes are frequent in elliptical galaxies, but the case of NGC 3311 might be particularly interesting for problems of dust lifetime and the role of cool gas in the central parts. We aim to use archival HST images and MUSE data to investigate the central dust structure of NGC 3311. We used the tool PyParadise to model the stellar population and extract the emission lines. The HST/ACS colour map reveals the known dust structures, but also blue spots, which are places of strong line emission. A dusty 'mini-jet' emanates from the centre. The distribution of the emission line gas matches the dust silhouette almost exactly. Close to the brightest Halpha emission, the ratio [NII]/Halpha resembles that of HII-regions; in the outer parts, [NII] gets stronger and is similar to LINER-like spectra. The gas kinematics is consistent with that of a rotating disc. The Doppler shifts of the strongest line emissions, which indicate the areas of highest star formation activity, smoothly fit into the disc symmetry. The metallicity is supersolar. The presence of neutral gas is indicated by the fit residuals of the stellar NaI D absorption line, which we interpret as interstellar absorption. We estimate the mass of the neutral gas to be of the order of the X-ray mass. The dynamical mass infers a stellar population of intermediate age, whose globular clusters have already been identified. Our findings can be harmonised in a scenario in which the star formation is triggered by the accretion of cold gas onto a pre-existing gas/dust disc or ring. Newly produced dust then contributes to the longevity of the dust.
