Ultra-cool Dwarfs from Large Area Surveys

TL;DR

This paper presents a method for selecting and confirming ultra-cool dwarf candidates from large sky surveys, utilizing photometric criteria, spectral confirmation, and proper motion analysis to identify brown dwarfs.

Contribution

Introduces a new photometric selection method for brown dwarf candidates using SDSS, 2MASS, and UKIDSS data, combined with spectral confirmation and proper motion estimation.

Findings

Successful identification of brown dwarf candidates

Effective spectral typing using multi-survey colors

Reliable proper motion measurements obtained

Abstract

We selected brown dwarf candidates from the seventh Data Release of the Sloan Digital Sky Survey (SDSS DR7) with new photometric selectioncriteria based on a parameteriaztion of well-known L and T dwarfs. Then we confirmed their status with SDSS spectra. The candidates without SDSS spectra are cross matched in the Two Micron All Sky Survey (2MASS) and the Fourth Data Release of the UKIRT Infrared Deep Sky Survey (UKIDSS DR4). With the help of colors based on SDSS, 2MASS and UKIDSS, we are able to estimate spectral types of our candidates. We obtain reliable proper motions using positional and epoch information downloaded direct from the survey databases.