New brown dwarf candidates in the Pleiades

TL;DR

This study identifies seven new brown dwarf candidates in the Pleiades through deep optical and infrared imaging, employing a novel data reduction technique and spectral fitting to confirm their nature.

Contribution

The paper introduces a new method for data reduction and candidate identification in wide-field imaging of star clusters, leading to discovery of brown dwarf candidates.

Findings

Seven new brown dwarf candidates identified

Effective data reduction technique developed

Candidates consistent with Pleiades age and distance

Abstract

We have performed deep, wide-field imaging on a ~0.4 deg^2 field in the Pleiades (Melotte 22). The selected field was not yet target of a deep search for low mass stars and brown dwarfs. Our limiting magnitudes are R ~ 22mag and I ~ 20mag, sufficient to detect brown dwarf candidates down to 40MJ. We found 197 objects, whose location in the (I, R - I) color magnitude diagram is consistent with the age and the distance of the Pleiades. Using CTK R and I as well as JHK photometry from our data and the 2MASS survey we were able to identify 7 new brown dwarf candidates. We present our data reduction technique, which enables us to resample, calibrate, and co-add many images by just two steps. We estimate the interstellar extinction and the spectral type from our optical and the NIR data using a two-dimensional chi^22 fitting.