DECam Survey for Low-Mass Stars and Substellar Objects in the UCL and LCC Subgroups of the Sco-Cen OB Association (SCOCENSUS)

TL;DR

This paper presents the first extensive survey of low-mass stars and substellar objects in the Sco-Cen OB association using DECam, resulting in a large catalog and candidate list that supports a universal initial mass function.

Contribution

Developed open source Python tools for processing large astronomical datasets and created a comprehensive catalog of low-mass and substellar candidates in Sco-Cen.

Findings

Catalog contains over 11 million point sources.

Identified 118 top candidate members and 348 good candidates.

Mass and luminosity functions align with a universal IMF.

Abstract

Using images taken with the Dark Energy Camera (DECam), the first extensive survey of low mass and substellar objects is made in the 15-20 Myr Upper Centaurus Lupus (UCL) and Lower Centaurus Crux (LCC) subgroups of the Scorpius Centaurus OB Association (Sco-Cen). Due to the size of our dataset (>2Tb) we developed an extensive open source set of python libraries to reduce our images, including astrometry, coaddition, and PSF photometry. Our survey consists of 29$\times$3 deg$^2$ fields in the UCL and LCC subgroups of Sco-Cen and the creation of a catalog with over 11 million point sources. We create a prioritized list of candidate for members in UCL and LCC, with 118 \emph{best} and another 348 \emph{good} candidates. We show that the luminosity and mass functions of our low mass and substellar candidates are consistent with measurements for the younger Upper Scorpius subgroup and estimates of a universal IMF, with spectral types ranging from M1 down to L1.