EROS light-curve database

¹ IRFU, CEA, Universite de Paris-Saclay, CEA, Irfu, 91191 Gif-sur-Yvette, France
² Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France
³ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
⁴ Université de Paris, CNRS, Astroparticule et Cosmologie, 75013 Paris, France
⁵ Sorbonne Universités, UPMC Univ Paris 6 et CNRS, UMR 7095, Institut d’Astrophysique de Paris, IAP, 75014 Paris, France
⁶ Université de Strasbourg, CNRS, Observatoire Astronomique, CNRS, UMR 7550, 67000 Strasbourg, France
⁷ Sorbonne Université, CNRS/IN2P3, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), 75005 Paris, France

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 19 September 2025
Accepted: 5 December 2025

Abstract

Context. The project called Expérience de Recherche d’Objets Sombres (EROS) carried out photometric surveys of dense stellar fields toward the Magellanic Clouds (LMC and SMC), the Galactic bulge and Galactic spiral arms in the period 1990-2003. The main goal of the experiment was to search for the Galactic dark matter in the form of massive compact objects (machos) through the gravitational microlensing effect.

Aims. The historical record of the flux variations in the monitored stars by EROS-2 will be a unique asset for time-domain astronomy and to complement current and future searches of transient sources.

Methods. We describe the set of light curves that was obtained with the EROS-2 program from 1996 to 2003, when more than 86 million stars were monitored. The set is publicly released through the Centre de Données de Strasbourg (CDS). This dataset includes 28.7 and 4.0 million light curves in the LMC and SMC, 42.9 million light curves in the Galactic bulge, and 10.4 million light curves toward the Galactic spiral arms and has several hundred measurements for each object. The data from EROS-1 are also being released.

Results. The object catalog, light curves, and images are accessible through the CDS portal. This is useful for determining the past behavior of newly discovered variable objects.