Dear All,
The 4m International Liquid Mirror Telescope (ILMT) is India’s first optical survey telescope, which has been continuously monitoring the zenith sky since its first light in April 2022 and has successfully completed four observing cycles until 2025. It covers an area of approximately 115 deg² per year, acquiring nearly 4 TB of high-quality imaging data in the SDSS g′, r′, and i′ filters. The images are fully preprocessed and astrometrically calibrated, with positional accuracies better than ~0.1 arcsec.
The telescope has a field of view (FoV) of ~22′ and, owing to its large 4m aperture, achieves a photometric depth of about 22 mag in the g′ band giving a higher photometric precision at fainter magnitudes. Additionally, zenith sky observation offers minimal atmospheric extinction, further improving the data quality. The observations are performed with daily cadence, providing a rich phase coverage for transient and variable sources. The dataset enables a wide range of scientific investigations, including but not limited to:
1) Variable Stars: This includes eclipsing binaries, RR Lyrae stars, Delta Scuti stars, long-period variables, and more. The availability of long-term photometric monitoring allows for phase-folded light curves, detailed modeling, and accurate parameter estimation.
2) Eruptive/Outburst Events: Transient outbursts are routinely detected in Galactic sources such as T Tauri stars and cataclysmic variables. These photometric observations, when combined with spectroscopic follow-up, enable comprehensive characterization of such events.
3) Active Galactic Nuclei (AGNs): The dataset contains extensive multi-band, long-term photometric coverage of various AGN classes, including QSOs, Seyfert galaxies, and blazars. It also includes sources exhibiting large-amplitude variability, which are of particular scientific interest.
4) Supernovae: One of the primary goals of the survey is the detection and characterization of supernovae within the ILMT FoV. So far, 22 such events have been captured, with a few already studied/being studied in detail.
The imaging data is now publicly available, and can be accessed using the following link. A flyer of the ILMT data archive is also attached with this email. We encourage the community to access the data and explore the science cases of interest. In case of any queries and problems, please feel free to contact us (you can email to: kuntal@aries.res.in).
Thanks and best regards,
-Kuntal