Difference Image Analysis of the OGLE-II Bulge Data. III. Catalog of 200,000 Candidate Variable Stars

TL;DR

This paper presents a catalog of over 200,000 candidate variable stars from OGLE-II Galactic Bulge data, utilizing Difference Image Analysis over three years, providing a valuable resource for stellar variability studies.

Contribution

First comprehensive catalog of variable stars from OGLE-II Galactic Bulge data using DIA, covering 11 square degrees with detailed light curves and initial calibration.

Findings

Catalog contains 221,801 light curves.

Approximate 10% contamination by spurious detections.

Part of the data is preliminarily calibrated.

Abstract

We present the first edition of a catalog of variable stars from OGLE-II Galactic Bulge data covering 3 years: 1997-1999. Typically 200-300 I band data points are available in 49 fields between -11 and 11 degrees in galactic longitude, totaling roughly 11 square degrees in sky coverage. Photometry was obtained using the Difference Image Analysis (DIA) software and tied to the OGLE data base with the DoPhot package. The present version of the catalog comprises 221,801 light curves. In this preliminary work the level of contamination by spurious detections is still about 10%. Parts of the catalog have only crude calibration, insufficient for distance determinations. The next, fully calibrated, edition will include the data collected in year 2000. The data is accessible via FTP. Due to the data volume, we also distribute DAT tapes upon request.