论文标题
M31的凸起的复杂结构
The Complex Structure of the Bulge of M31
论文作者
论文摘要
M31的凸起是在银河凸起的性质及其结构与凸起形成机制及其随后的进化的背景下感兴趣的。借助Astrosat上的紫色仪器，我们观察到M31在五个远紫外线（FUV）和接近紫外线（NUV）滤波器中以1“空间分辨率。用于凸起的亮度分布的模型是使用紫外数据和紫外线图像拟合algorithm galfit的五个图像和五个图像的模型。 （$ \ simeq2.1 $ to 2.5）与以前的研究相似，但$ r_e $值（$ \ simeq0.5 $ to 0.6 kpc）凸出区域中的凸起区域在降低的凸出光线后，使用多型脉冲在NUV和FUV波长中恢复了凸出的凸起。经典凸起和伪内的预期值。
The bulge of M31 is of interest in the context of the nature of galactic bulges and how their structure relates to bulge formation mechanisms and their subsequent evolution. With the UVIT instrument on AstroSat, we have observed the bulge of M31 in five far ultraviolet (FUV) and near ultraviolet (NUV) filters at 1" spatial resolution. Models for the luminosity distribution of the bulge are constructed using the UVIT data and the galaxy image-fitting algorithm GALFIT. We fit the bulge without nuclear region with a Sersic function the five images and find Sersic indices ($\simeq2.1$ to 2.5) similar to previous studies but smaller $R_e$ values ($\simeq0.5$ to 0.6 kpc). When the images include the nuclear region, a multicomponent model is used to find the best-fit. We use an 8-component fit for the FUV 148nm image, which has the highest sensitivity. The other images (169 to 279 nm) are fit with 4-component models. The dust lanes in the bulge region are recovered in the residual image after subtraction of the bright bulge light using the multicomponent model. The dust lanes show that M31's nuclear spiral is visible in absorption at NUV and FUV wavelengths. The bulge images show boxy contours in all five UVIT wavebands, which is confirmed by fitting using GALFIT. The Sersic indices of $\sim$2.1-2.5 are intermediate between expected values for a classical bulge and for a pseudobulge. The boxiness of the bulge provides further evidence that M31's bulge has contributions from a classical bulge and a pseudobulge.
