论文标题
hi，快速观察到的大螺旋星系
HI content of massive red spiral galaxies observed by FAST
论文作者
论文摘要
Guo等人在光学上选择了279个巨大的红色螺旋。 （2020年），其中苜蓿调查已经观察到了166个星系。在这项工作中，我们使用五百米的光圈球形射电望远镜（快速）观察到其余113个巨大的红色螺旋星系的HI含量。在113个星系中，有75个具有HI检测，具有大于4.7的信噪比（S/N）。与苜蓿调查所观察到的同一样品中的红色螺旋相比，速度观察到的星系平均具有更高的S/N，并且可以达到较低的HI质量。为了调查为什么许多红色螺旋都包含大量的HI质量，我们使用DESI传统成像调查观察到的图像检查了大型红色螺旋的颜色曲线。我们发现，对于苜蓿和快速样品，带有HI检测的星系比没有HI检测的星系具有更蓝的外盘。对于具有HI检测的星系，在半径上存在星系HI质量和G-R颜色之间存在明显的相关性：HI质量较高的星系具有较浅的外盘。结果表明，光学选择的巨大红色螺旋不会完全淬灭，并且在许多星系中观察到的HI气体可能存在于其外蓝色磁盘中。
A sample of 279 massive red spirals was selected optically by Guo et al. (2020), among which 166 galaxies have been observed by the ALFALFA survey. In this work, we observe HI content of the rest 113 massive red spiral galaxies using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). 75 of the 113 galaxies have HI detection with a signal-to-noise ratio (S/N) greater than 4.7. Compared with the red spirals in the same sample that have been observed by the ALFALFA survey, galaxies observed by FAST have on average a higher S/N, and reach to a lower HI mass. To investigate why many red spirals contain a significant amount of HI mass, we check color profiles of the massive red spirals using images observed by the DESI Legacy Imaging Surveys. We find that galaxies with HI detection have bluer outer disks than the galaxies without HI detection, for both ALFALFA and FAST samples. For galaxies with HI detection, there exists a clear correlation between galaxy HI mass and g-r color at outer radius: galaxies with higher HI masses have bluer outer disks. The results indicate that optically selected massive red spirals are not fully quenched, and the HI gas observed in many of the galaxies may exist in their outer blue disks.
