1318 new variable stars in a 0.25 square degree region of the Galactic plane^*

¹ Max-Planck Institüt für Astronomie, Königstuhl 17, Heidelberg 69117, Germany e-mail: vrmiller@live.com;[afonso,henning]@mpia.de
² Department of Physics and Astronomy, Private Bag 4800, University of Canterbury, New Zealand e-mail: Michael.Albrow@canterbury.ac.nz

Received: 23 December 2009
Accepted: 14 May 2010

Abstract

We conducted a deep photometric survey of a 0.5° × 0.5° area of the Galactic plane using the WFI instrument on the 2.2-m ESO telescope on La Silla, Chile. The dataset comprises a total of 267 R-band images, 204 from a 16 day observation run in 2005, supplemented by 63 images from a six week period in 2002. Our reduction employed the new numerical kernel difference image analysis method as implemented in the pysis3 code and resulted in more than 500 000 lightcurves of stars down to a magnitude limit of R ~ 24.5. A search for variable stars resulted in the detection of 1318 variables of different types. 1011 of these are eclipsing or contact binary stars. A number of the contact binaries have low mass-ratios and several of the detached binaries appear to have low-mass components. Three candidate contact binaries have periods at the known cut off including two with periods lower than any previously published. Also identified are 3 possible pre-main sequence detached eclipsing binaries.