arXiv 2106.017522021-06-30astro-ph.IM

Gaia BP/RP低分辨光谱的内定标

Internal calibration of Gaia BP/RP low-resolution spectra

J. M. Carrasco, M. Weiler, C. Jordi, C. Fabricius, F. De Angeli, D. W. Evans, F. van Leeuwen, M. Riello, P. Montegriffo

备注：: 20 pages, 22 figures
发表信息：: A&A 652, A86 (2021)
DOI：: 10.1051/0004-6361/202141249

摘要：

完整的第三次盖亚数据发布将提供用蓝色和红色盖亚无狭缝光谱仪获得的校准光谱。面对盖亚光谱校准的主要挑战是在任务期间没有灯光谱或平坦场可用。此外，相对于棱镜的色散的线扩展函数的显著尺寸产生污染光谱的相邻位置的外来光子。这使得校准特殊，不同于标准方法。本文详细介绍了Gaia星表分光光度数据的内定标模型。内部校准的主要目的是将所有历元光谱置于共同的通量和像素（伪波长）尺度上，同时考虑到焦平面上的变化和随时间的变化，从同一源的所有观测中产生平均光谱。为了在一个共同的平均通量和伪波长尺度描述所有的观测，我们通过基函数构建了一个合适的表示内部校准的平均光谱，我们通过离散卷积描述了非校准的历元光谱和校准的平均光谱之间的转换，参数化卷积核恢复相关系数。这里提出的模型是能够将所有的观察到一个平均仪器，允许不同的来源和观察到的不同仪器条件下获得的比较沿任务和平均光谱的产生从一些相同的来源的观察。该模型的输出提供了内部平均光谱，不是作为采样函数（通量和波长），而是作为基函数的线性组合，尽管采样光谱可以很容易地从中导出。

英文摘要：

The full third Gaia data release will provide the calibrated spectra obtained with the blue and red Gaia slit-less spectrophotometers. The main challenge when facing Gaia spectral calibration is that no lamp spectra or flat fields are available during the mission. Also, the significant size of the line spread function with respect to the dispersion of the prisms produces alien photons contaminating neighbouring positions of the spectra. This makes the calibration special and different from standard approaches. This work gives a detailed description of the internal calibration model to obtain the spectrophotometric data in the Gaia catalogue. The main purpose of the internal calibration is to bring all the epoch spectra onto a common flux and pixel (pseudo-wavelength) scale, taking into account variations over the focal plane and with time, producing a mean spectrum from all the observations of the same source. In order to describe all observations in a common mean flux and pseudo-wavelength scale, we construct a suitable representation of the internally calibrated mean spectra via basis functions and we describe the transformation between non calibrated epoch spectra and calibrated mean spectra via a discrete convolution, parametrising the convolution kernel to recover the relevant coefficients. The model proposed here is able to combine all observations into a mean instrument to allow the comparison of different sources and observations obtained with different instrumental conditions along the mission and the generation of mean spectra from a number of observations of the same source. The output of this model provides the internal mean spectra, not as a sampled function (flux and wavelength), but as a linear combination of basis functions, although sampled spectra can easily be derived from them.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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