DL3 example dataset from Crab Nebula observations with LST-1

This repository contains a subsample of DL3 files from Crab Nebula observations used in the performance study of the Large-Sized Telescope prototype (LST-1, https://www.lst1.iac.es/) for the Cherenkov Telescope Array Observatory (CTAO, https://www.ctao.org/). The results of this performance study [1] were obtained from a larger sample of the Crab Nebula observations than the one compiled here.

This reduced dataset aims to serve as an example for analyzing observed data by one of the telescopes that will be part of the future CTAO. These data files are intended to be used in the hands-on sessions for the 1D high-level DL3 analysis in the CTAO Shcool (https://www.school.cta-observatory.org/).

Information about the data and the reduction process

The DL3 files included in this repository are a subsample of 1.9 hours of Crab Nebula observations data taken on March 4th and 5th, 2022. They were produced with cta-lstchain in FITS format following the Gamma-ray Astronomy Data Format (GADF; [3]). They can be directly read and analyzed with Gammapy [4]. Data were processed following the source-independent analysis approach described in [1]. The gamma-hadron separation and directional cuts (gammaness and theta parameters) for the gamma-ray-like event selection were chosen to keep 70% of gamma-ray-like simulated events in each bin of reconstructed energy. The point-like instrument response functions (IRF) were produced (using pyirf [5]) using the same energy-dependent efficiency cuts from simulated gamma rays in an all-sky grid of pointing positions. Final IRFs for each observation run were produced by linear interpolation among the closest simulated pointing nodes to the actual telescope pointing while observing the Crab Nebula.

List of files

• dl3_LST-1.Run07253.fits
• dl3_LST-1.Run07254.fits
• dl3_LST-1.Run07255.fits
• dl3_LST-1.Run07256.fits
• dl3_LST-1.Run07274.fits
• dl3_LST-1.Run07275.fits
• dl3_LST-1.Run07276.fits
• dl3_LST-1.Run07277.fits
• hdu-index.fits.gz
• obs-index.fits.gz

Acknowledgements

The production of these files has been possible thanks to the LST Collaboration work at different levels, namely, hardware and software development, data-taking, production of simulations, and data analysis.

References

[1] H. Abe et al 2023 ApJ 956 80 (DOI 10.3847/1538-4357/ace89d)

[2] cta-lstchain: https://doi.org/10.5281/zenodo.10849683

[3] Data formats for gamma-ray astronomy. https://github.com/open-gamma-ray-astro/gamma-astro-data-formats

[4] A&A, 678, A157 (2023) DOI https://doi.org/10.1051/0004-6361/202346488 

[5] pyirf: https://doi.org/10.5281/zenodo.8348922