Eclipsing binaries suitable for distance determination in the Andromeda galaxy

Abstract

The Local Group galaxies constitute a fundamental step in the definition of cosmic distance scale. Therefore, obtaining accurate distance determinations to the galaxies in the Local Group, and notably to the Andromeda Galaxy (M31), is essential to determining the age and evolution of the Universe. With this ultimate goal in mind, we started a project to use eclipsing binaries as distance indicators to M31. Eclipsing binaries have been proved to yield direct and precise distances that are essentially assumption free. To do so, high-quality photometric and spectroscopic data are needed. As a first step in the project, broad band photometry (in Johnson B and V) has been obtained in a region (34'x34') at the North-Eastern quadrant of the galaxy over 5 years. The data, containing more than 250 observations per filter, have been reduced by means of the so-called difference image analysis technique and the DAOPHOT program. A catalog with 236238 objects with photometry in both B and V passbands has been obtained. The catalog is the deepest (V<25.5 mag) obtained so far in the studied region and contains 3964 identified variable stars, with 437 eclipsing binaries and 416 Cepheids. The most suitable eclipsing binary candidates for distance determination have been selected according to their brightness and from the modelling of the obtained light curves. The resulting sample includes 24 targets with photometric errors around 0.01 mag. Detailed analysis (including spectroscopy) of some 5-10 of these eclipsing systems should result in a distance determination to M31 with a relative uncertainty of 2-3% and essentially free from systematic errors, thus representing the most accurate and reliable determination to date.

12 pages, 9 figures; accepted for publication in A&A; see electronic tables and full resolution images at http://www.am.ub.es/~fvilarde/download/A+A/

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Cited by in corpus (26)

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• Large Magellanic Cloud Near-Infrared Synoptic Survey. II. The Wesenheit relations and their application to the Distance scale
• First detection and characterization of symbiotic stars in M31
• Improving the surface brightness-color relation for early-type stars using optical interferometry
• A comprehensive study of Cepheid variables in the Andromeda galaxy. Period distribution, blending and distance determination
• Properties of M31. II: A Cepheid disk sample derived from the first year of PS1 PAndromeda data
• New Luminous Blue Variables in the Andromeda galaxy
• The horizontal branch luminosity vs metallicity in M31 globular clusters
• Cepheids in M31 - The PAndromeda Cepheid sample
• J004457+4123 (Sharov 21): not a remarkable nova in M31 but a background quasar with a spectacular UV flare
• Optical flares from the faint mid-dM star 2MASS J00453911+4140396
• Properties of M31. V: 298 Eclipsing Binaries from PAndromeda
• A cold gas reservoir to fuel M31 nuclear black hole and stellar cluster
• No Evidence for Periodic Variability in the Light Curve of Active Galaxy J0045+41
• A Mote in Andromeda's Disk: a Misidentified Periodic AGN Behind M31
• Hide and seek between Andromeda's halo, disk, and giant stream
• The Discovery of QSOs Behind M31 and M33
• The first transition Wolf-Rayet WN/C star in M31
• A New Luminous Blue Variable in M31
• Double-mode Cepheids in M31
• VI-Band Follow-Up Observations of Ultra-Long-Period Cepheid Candidates in M31
• M31 PAndromeda Cepheid sample observed in four HST bands
• A Spectroscopic Search for High Mass X-ray Binaries in M31
• Dust in the Eye of Andromeda
• The first analysis of extragalactic binary-orbit precession