Abstract
The variability induced by precipitable water vapour (PWV) can heavily affect the accuracy of time-series photometric measurements gathered from the ground, especially in the near-infrared. We present here a novel method of modelling and mitigating this variability, as well as open-sourcing the developed tool -- Umbrella. In this study, we evaluate the extent to which the photometry in three common bandpasses (r', i', z'), and SPECULOOS' primary bandpass (I+z'), are photometrically affected by PWV variability. In this selection of bandpasses, the I+z' bandpass was found to be most sensitive to PWV variability, followed by z', i', and r'. The correction was evaluated on global light curves of nearby late M- and L-type stars observed by SPECULOOS' Southern Observatory (SSO) with the I+z' bandpass, using PWV measurements from the LHATPRO and local temperature/humidity sensors. A median reduction in RMS of 1.1% was observed for variability shorter than the expected transit duration for SSO's targets. On timescales longer than the expected transit duration, where long-term variability may be induced, a median reduction in RMS of 53.8% was observed for the same method of correction.
Original language | English |
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Pages (from-to) | 2661–2670 |
Number of pages | 10 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 518 |
Issue number | 2 |
Early online date | 4 Nov 2022 |
DOIs | |
Publication status | Published - Jan 2023 |
Bibliographical note
Accepted for publication in MNRAS, 10 pages, 7 figures, 3 tablesKeywords
- atmospheric effects
- techniques: photometric