MeerLICHT phot. of hot sub-luminous stars

A dedicated frequency determination technique is developed and applied to the selected candidates to determine their dominant variability using time-series data from MeerLICHT and Gaia DR3. We explore the power of both datasets in determining the dominant frequency. Using the g-i colour, MeerLICHT offers a colour-magnitude diagram that is comparable in quality to that of Gaia DR3.

The former, however, is more sensitive to fainter objects. The MeerLICHT colour-colour diagrams allow for the study of different stellar populations. The frequency analysis of MeerLICHT and Gaia DR3 data demonstrates the superiority of our MeerLICHT multi-colour photometry to estimate the dominant frequency compared to the sparse Gaia DR3 data.

MeerLICHT's multiband photometry leads to the discovery of high-frequency faint subdwarfs. Continued observations tuned to asteroseismology will allow for mode identification using the method of amplitude ratios. Our MeerLICHT results are a proof-of-concept for the capacity of the BlackGEM instrument currently in commissioning at ESO's La Silla Observatory in Chile.