论文标题
HR 4796A碎片磁盘的多播GPI成像
Multiband GPI Imaging of the HR 4796A Debris Disk
论文作者
论文摘要
我们已经获得了Gemini Planet Imager（GPI）J-，H-，K1-和K2规格观测值，该观测值周围是年轻的，主要的恒星HR 4796a周围的标志性碎片环。我们将几个点传播函数（PSF）减法技术应用于观测值（mask and-and-Interpaly，rdi-nmf，rdi-klip和adi-klip），以测量磁盘的几何参数和散射相函数。为了了解与PSF减法相关的系统误差，我们还使用Markov Chain Monte Carlo框架和磁盘的简单模型对观测值进行了前进模型。我们发现，磁盘几何参数的测量值很强，我们的所有分析都会产生一致的结果。然而，尽管进行了广泛的测试，但散射相函数的测量对于从PSF提取的图像中重建的测量很具有挑战性。结果，我们使用磁盘建模估算了散射相函数。我们搜索了相对于GPI过滤器的散射期函数的依赖性，但没有发现。我们将H频段散射相位与Hubble空间望远镜在视觉波长下测量的相位，并在小散射角处发现了蓝色的蓝色，并在大散射角处发现了与大晶粒的预测和实验室测量相一致的。最后，我们成功地使用了由硅酸盐，碳和金属铁组成的空心球的分布来成功建模球H2 HR 4796a散射相位函数。
We have obtained Gemini Planet Imager (GPI) J-, H-, K1-, and K2-Spec observations of the iconic debris ring around the young, main-sequence star HR 4796A. We applied several point-spread function (PSF) subtraction techniques to the observations (Mask-and-Interpolate, RDI-NMF, RDI-KLIP, and ADI-KLIP) to measure the geometric parameters and the scattering phase function for the disk. To understand the systematic errors associated with PSF subtraction, we also forward-modeled the observations using a Markov Chain Monte Carlo framework and a simple model for the disk. We found that measurements of the disk geometric parameters were robust, with all of our analyses yielding consistent results; however, measurements of the scattering phase function were challenging to reconstruct from PSF-subtracted images, despite extensive testing. As a result, we estimated the scattering phase function using disk modeling. We searched for a dependence of the scattering phase function with respect to the GPI filters but found none. We compared the H-band scattering phase function with that measured by Hubble Space Telescope STIS at visual wavelengths and discovered a blue color at small scattering angles and a red color at large scattering angles, consistent with predictions and laboratory measurements of large grains. Finally, we successfully modeled the SPHERE H2 HR 4796A scattered phase function using a distribution of hollow spheres composed of silicates, carbon, and metallic iron.
