标题： 罗博极样本的光学偏振标准 显示英文标题

标题： The RoboPol sample of optical polarimetric standards

摘要： 光学偏振计通常使用已知且稳定的恒星的测量结果进行校准。 然而，天空中缺乏这样的恒星。 目前可用的许多标准恒星由于亮度较高，不适合用于中型和大型望远镜。 此外，我们发现，一些使用的偏振标准实际上可能是变星，或者其偏振参数与目录中的值不同。 我们的目标是建立一个稳定的标准样本，可用于校准线性光学偏振计，准确度达到分数偏振的$10^{-3}$。 在过去五年中，我们一直在对一组由分布在北天的107颗恒星组成的标准候选者进行监测活动。 我们分析了这些恒星的线性偏振变化，并考虑了分数偏振测量的非高斯性质。 对于九颗恒星的子样本，我们还进行了多波段偏振测量。 我们创建了一个新的65颗恒星的目录（见表2），这些恒星稳定，测量的偏振参数不确定性小，可以用于中型和大型望远镜的偏振计校准。 显示英文摘要

摘要： Optical polarimeters are typically calibrated using measurements of stars with known and stable polarization parameters. However, there is a lack of such stars available across the sky. Many of the currently available standards are not suitable for medium and large telescopes due to their high brightness. Moreover, as we find, some of the used polarimetric standards are in fact variable or have polarization parameters that differ from their cataloged values. Our goal is to establish a sample of stable standards suitable for calibrating linear optical polarimeters with an accuracy down to $10^{-3}$ in fractional polarization. For five years, we have been running a monitoring campaign of a sample of standard candidates comprised of 107 stars distributed across the northern sky. We analyzed the variability of the linear polarization of these stars, taking into account the non-Gaussian nature of fractional polarization measurements. For a subsample of nine stars, we also performed multiband polarization measurements. We created a new catalog of 65 stars (see Table 2) that are stable, have small uncertainties of measured polarimetric parameters, and can be used as calibrators of polarimeters at medium- and large-size telescopes.