The Wendelstein Calar Alto Pixellensing Project (WeCAPP): the M31 Nova catalogue

TL;DR

This paper presents a comprehensive catalogue of 91 novae in M31 detected via the WeCAPP project, analyzing their light curves, classifications, and potential recurrent events to enhance understanding of nova behavior and contribute to dark matter research.

Contribution

The study provides the largest CCD-based optical nova light curve sample for M31, applying nova taxonomy and analyzing decline laws, with identification of potential recurrent novae and optical counterparts to X-ray sources.

Findings

Detected 91 novae benefiting from high-cadence imaging.

Classified novae into various types, including 29 S-class.

Identified 4 potential recurrent novae.

Abstract

We present light curves from the novae detected in the long-term, M31 monitoring WeCAPP project. The goal of WeCAPP is to constrain the compact dark matter fraction of the M31 halo with microlensing observations. As a by product we have detected 91 novae benefiting from the high cadence and highly sensitive difference imaging technique required for pixellensing. We thus can now present the largest CCD and optical filters based nova light curve sample up-to-date towards M31. We also obtained thorough coverage of the light curve before and after the eruption thanks to the long-term monitoring. We apply the nova taxonomy proposed by Strope et al. (2010) to our nova candidates and found 29 S-class novae, 10 C-class novae, 2 O-class novae and 1 J-class nova. We have investigated the universal decline law advocated by Hachichu and Kato (2006) on the S-class novae. In addition, we correlated our catalogue with the literature and found 4 potential recurrent novae. Part of our catalogue has been used to search for optical counter-parts of the super soft X-ray sources detected in M31 (Pietsch et al. 2005). Optical surveys like WeCAPP, and coordinated with multi-wavelength observation, will continue to shed light on the underlying physical mechanism of novae in the future.