OGLE Atlas of Classical Novae II. Magellanic Clouds

P. Mroz, A. Udalski, R. Poleski, I. Soszynski, M. K. Szymanski, G. Pietrzynski, L. Wyrzykowski, K. Ulaczyk, S. Kozlowski, P. Pietrukowicz, J. Skowron

Published 2015-11-19Version 1

The population of classical novae in the Magellanic Clouds was poorly known because of a lack of systematic studies. There were some suggestions that nova rates per unit mass in the Magellanic Clouds were higher than in any other galaxy. Here, we present an analysis of data collected over sixteen years by the OGLE survey with the aim of characterizing nova population in the Clouds. We found twenty eruptions of novae, half of them are new discoveries. We robustly measure the nova rates of $2.4 \pm 0.8$ yr$^{-1}$ (LMC) and $0.9 \pm 0.4$ yr$^{-1}$ (SMC) and confirm that K-band luminosity-specific nova rates in both Clouds are 2-3 times higher than in other galaxies. This can be explained by the star formation history in the Magellanic Clouds, specifically a re-ignition of the star formation rate a few Gyr ago. We also present the discovery of an intriguing system OGLE-MBR133.25.1160 which mimics recurrent nova eruptions.