RGB photometric calibration of 15 million Gaia stars
RGB photometric calibration of 15 million Gaia stars
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DOI：
10.1093/mnras/stab2124
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发表时间：
2021-08-17
影响因子：
4.8
通讯作者：
Sanchez de Miguel, Alejandro
中科院分区：
文献类型：
--
作者：
Cardiel, Nicolas;Zamorano, Jaime;Sanchez de Miguel, Alejandro
虽然最近出版了一个合成RGB星等目录，为1346颗亮星的样本提供光度数据，但由于参考星的数量很少，考虑到它们分布在整个天球，事实上，它们被限制在约翰逊V < 6.6等。这项工作提出了类似的1500万颗恒星的合成RGB星等比盖亚G = 18等，利用参考亮星星样本的RGB幅度与Gaia EDR 3提供的相应高质量光度G、G（BP）和G（RP）幅度之间的校准。校准仅限于-0.5 < G（BP）- G（RP）< 2.0等的恒星，目的是在+/-0.1等的误差区间内预测RGB星等。由于参考亮星星样本主要是附近的恒星，金属丰度略低于太阳，预测中的系统变化是预期的，这是在恒星大气模型的帮助下建模的。当仅对几乎不受星际灭绝影响且金属丰度与明亮星星样本的中值兼容的恒星应用校准时，这些偏差被限制在+/- 0.1等间隔内。在天空的每个区域都有大量的盖亚源，应该可以保证高质量的RGB光度校准。
Although a catalogue of synthetic RGB magnitudes, providing photometric data for a sample of 1346 bright stars, has been recently published, its usefulness is still limited due to the small number of reference stars available, considering that they are distributed throughout the whole celestial sphere, and the fact that they are restricted to Johnson V < 6.6 mag. This work presents synthetic RGB magnitudes for similar to 15 million stars brighter than Gaia G = 18 mag, making use of a calibration between the RGB magnitudes of the reference bright star sample and the corresponding high-quality photometric G, G(BP), and G(RP) magnitudes provided by the Gaia EDR3. The calibration has been restricted to stars exhibiting -0.5 < G(BP) - G(RP) < 2.0 mag, and aims to predict RGB magnitudes within an error interval of +/- 0.1 mag. Since the reference bright star sample is dominated by nearby stars with slightly undersolar metallicity, systematic variations in the predictions are expected, as modelled with the help of stellar atmosphere models. These deviations are constrained to the +/- 0.1-mag interval when applying the calibration only to stars scarcely affected by interstellar extinction and with metallicity compatible with the median value for the bright star sample. The large number of Gaia sources available in each region of the sky should guarantee high-quality RGB photometric calibrations.