Adaptive elliptical aperture photometry: A software package for high-cadence ground-based photometry I. Application to rapid oscillators observed from SAAO
Adaptive elliptical aperture photometry: A software package for high-cadence ground-based photometry I. Application to rapid oscillators observed from SAAO
复制标题
自适应椭圆孔径光度测量：高节奏地基光度测量软件包 I. 在 SAAO 观测到的快速振荡器中的应用
DOI：
10.1051/0004-6361/201935640
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发表时间：
2019
影响因子：
6.5
通讯作者：
Bowman D
中科院分区：
文献类型：
--
作者：
Bowman D
现代太空望远镜目前正在为天空的一大部分提供高精度的光曲线，因此许多新的变星正在被发现。然而，一些恒星具有周期变化，周期在分钟级，需要高节奏的光度测量来探索相关的物理机制。通常需要不到一分钟的节奏来消除奈奎斯特的模糊性并确认快速变化，这迫使观察者获得高节奏的地面光度测量。目的我们的目标是提供一个现代软件包，以减少地面光度时间序列数据，并提供优化的(差分)光曲线。为了产生高质量的光曲线，使傅里叶光谱中短周期变化的幅度信噪比最大化，我们需要自适应椭圆孔径光度测量，因为这比使用固定半径的圆形光圈的孔径光度测量具有显著的优势。方法使用南非天文台(SAAO)的高节奏地面光度测量来演示我们的代码方法及其优势。此外，我们使用我们的软件包搜索了三颗候选roAp恒星的快速振荡。结果我们证明，我们的流水线代表着光曲线质量的显著改善，并将其提供给社区用于不同的仪器和天文台。我们利用HD 158596、HD 166542和HD 181810这三颗AP星的B数据，寻找并证明了在∼1 mmag以下的高频RoAp脉动的缺失。结论我们证明了高频脉动模在提取短周期变率方面的显著改进，并讨论了在三颗AP星中零探测的意义。
ContextModern space telescopes are currently providing high-precision light curves for a large fraction of the sky, such that many new variable stars are being discovered. However, some stars have periodic variability with periods on the order of minutes and require high-cadence photometry to probe the physical mechanisms responsible. A cadence of less than a minute is often required to remove Nyquist ambiguities and confirm rapid variability, which forces observers to obtain high-cadence ground-based photometry.AimsWe aim to provide a modern software package to reduce ground-based photometric time series data and deliver optimised (differential) light curves. To produce high-quality light curves, which maximise the amplitude signal-to-noise ratio of short-period variability in a Fourier spectrum, we require adaptive elliptical aperture photometry as this represents a significant advantage compared to aperture photometry using circular apertures of fixed radii.MethodsThe methodology of our code and its advantages are demonstrated using high-cadence ground-based photometry from the South African Astronomical Observatory (SAAO) of a confirmed rapidly oscillating Ap (roAp) star. Furthermore, we employed our software package to search for rapid oscillations in three candidate roAp stars.ResultsWe demonstrate that our pipeline represents a significant improvement in the quality of light curves, and we make it available to the community for use with different instruments and observatories. We search for and demonstrate the lack of high-frequency roAp pulsations to a limit of ∼1 mmag usingBdata in the three Ap stars HD 158596, HD 166542, and HD 181810.ConclusionsWe demonstrate the significant improvement in the extraction of short-period variability caused by high-frequency pulsation modes, and discuss the implication of null detections in three Ap stars.