Binary Lenses in OGLE III EWS Database. Season 2005

TL;DR

This paper reports the discovery of nine new binary lens candidates and four double source events from the OGLE-III 2005 data, analyzing their properties and mass ratios to distinguish planetary systems from binary stars.

Contribution

It introduces nine new binary lens candidates from OGLE-III 2005 data and analyzes their mass ratios, expanding the catalog of known binary microlensing events.

Findings

Nine new binary lens candidates identified.

Four events interpreted as double source lensing.

Most models have mass ratios between 0.1 and 1.0.

Abstract

We present nine new binary lens candidates from OGLE-III Early Warning System database for the season of 2005. We have also found four events interpreted as single mass lensing of double sources. The candidates have been selected by visual light curves inspection. Examining the models of binary lenses in our previous studies (10 caustic crossing events of OGLE-II seasons 1997--1999 and 34 binary lens events of OGLE-III seasons 2002--2004, including one planetary event), in this work and in three publications concerning planetary events of season 2005, we find four cases of extreme mass ratio binaries (q<0.01), and almost all other models with mass ratios in the range 0.1<q<1.0, which may indicate the division between planetary systems and binary stars.