Astro-photometric study of M37 with Gaia and wide-field ugi-imaging

TL;DR

This study combines Gaia astrometry with wide-field ugi imaging to identify white dwarf members in M37, including a unique planetary nebula central star, and provides a comprehensive catalog and atlas of the cluster field.

Contribution

It introduces a novel calibration method for wide-field imaging using Gaia data and identifies a rare planetary nebula central star in M37.

Findings

Seven white dwarf candidates identified, including a planetary nebula central star.

Developed software routines for distortion calibration applicable to other instruments.

Publicly released a detailed catalog and three-color atlas of M37.

Abstract

We present an astrometric and photometric wide-field study of the Galactic open star cluster M37 (NGC 2099). The studied field was observed with ground-based images covering a region of about four square degrees in the Sloan-like filters ugi. We exploited the Gaia catalogue to calibrate the geometric distortion of the large field mosaics, developing software routines that can be also applied to other wide-field instruments. The data are used to identify the hottest white dwarf (WD) member candidates of M37. Thanks to the Gaia EDR3 exquisite astrometry we identified seven such WD candidates, one of which, besides being a high-probability astrometric member, is the putative central star of a planetary nebula. To our knowledge, this is a unique object in an open cluster, and we have obtained follow-up low-resolution spectra that are used for a qualitative characterisation of this young WD. Finally, we publicly release a three-colour atlas and a catalogue of the sources in the field of view, which represents a complement of existing material.