Tracing the structure of the Milky Way with detached eclipsing binaries from the VVV survey – I. The method and initial results★

Abstract

We present the first results of a project aiming to trace the spatial structure of the Milky Way using detached eclipsing binaries (DEBs) as distance indicators. A sample of DEBs from the OGLE-II catalogue was selected and their near infrared photometry was taken from the Vista Variables in the Via Lactea (VVV) survey. The I band OGLE-II light curves are used to create models of the DEBs, which together with the VVV photometry are compared with a set of theoretical isochrones. After correcting for stellar reddening, we find a set of absolute physical parameters of components of a given binary, including absolute magnitudes and distances.With this approach we can calculate the distances with the precision better than 5 per cent. Even though we have a few systems, the distribution is not homogeneous along the line of sight, and appears to follow the overall structure of the Galaxyseveral spiral arms and the Bulge are distinguishable. A number of systems can be seen behind the Bulge, reaching even the distance to the Sagittarius dwarf galaxy.

Stellar variability in the VVV survey: overview and first results

“…In order to get an unbiased picture on Galactic structures traced by these stars, both the rate and precision in the detection of periodic signals have to be sufficiently high. The time-domain coverage at the present stage of the VVV Survey is not yet sufficiently large for conducting variability searches at high completeness, therefore our current investigations are limited to already known samples of distance indicators (Helminiak et al 2013;Dékány et al 2013b). However, we are already in the position to give estimates on the future signal detection performance in VVV based on the time-series data of the 8 VVV bulge fields with more than 60 epochs, which have a partial overlap with the highly complementary optical time-domain survey OGLE-III (Soszyński 2009;Soszyński et al 2011a).…”

“…As an example of their use in astrophysics, a method to use the VVV data for tracing the structure of the Milky Way with detached eclipsing binaries (DEBs) was introduced in Helminiak et al (2013). The idea behind the method is that one can calculate the distance by comparing the derived absolute magnitudes from the model with the observed ones.…”

The VISTA Variables in the Vía Láctea infrared variability catalogue (VIVA-I)

“…Minniti et al 2015;Navarro et al 2017Navarro et al , 2018Navarro et al , 2019, and eclipsing binaries (e.g. Torres et al 2010;Angeloni et al 2012;Hełminiak et al 2013;Deleuil et al 2018). On the other hand, new studies based on IR variability data at low Galactic latitudes may now become more accessible.…”

Physical Parameters of Northern Eclipsing Binaries in the Catalina Sky Survey

“…There is no doubt that eclipsing binaries (hereafter EBs), and specifically detached double-lined EBs without mass transfer, are forerunners in modern stellar astrophysics. Not only do they provide the prime tool for the validation of the current stellar structure and evolution models but also a wealth of fundamental information that ultimately contributes to our understanding of the structure and evolution of galaxies, including our own (Hełminiak et al 2013;Pietrzyński et al 2013;Graczyk et al 2014). In the last few decades, a long list of astronomical sky surveys enriched the astronomical databases with not only a huge amount of newly discovered EBs, but also with higher photometric precision and different wavelengths in a wide range of magnitudes, including, for instance, Kepler (Kirk et al 2016) and the Wide-field Infrared Survey Explorer (WISE; Chen et al 2018).…”