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Media type:
E-Article
Title:
Beyond the Local Volume. I. Surface Densities of Ultracool Dwarfs in Deep HST/WFC3 Parallel Fields
Contributor:
Aganze, Christian;
Burgasser, Adam J.;
Malkan, Mathew;
Theissen, Christopher A.;
Tejada Arevalo, Roberto A.;
Hsu, Chih-Chun;
Bardalez Gagliuffi, Daniella C.;
Ryan, Russell E.;
Holwerda, Benne
Published:
American Astronomical Society, 2022
Published in:
The Astrophysical Journal, 924 (2022) 2, Seite 114
Language:
Not determined
DOI:
10.3847/1538-4357/ac35ea
ISSN:
0004-637X;
1538-4357
Origination:
Footnote:
Description:
Abstract Ultracool dwarf stars and brown dwarfs provide a unique probe of large-scale Galactic structure and evolution; however, until recently spectroscopic samples of sufficient size, depth, and fidelity have been unavailable. Here, we present the identification of 164 M7-T9 ultracool dwarfs in 0.6 deg2 of deep, low-resolution, near-infrared spectroscopic data obtained with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) instrument as part of the WFC3 Infrared Spectroscopic Parallel Survey and the 3D-HST survey. We describe the methodology by which we isolate ultracool dwarf candidates from over 200,000 spectra, and show that selection by machine-learning classification is superior to spectral index-based methods in terms of completeness and contamination. We use the spectra to accurately determine classifications and spectrophotometric distances, the latter reaching to ∼2 kpc for L dwarfs and ∼400 pc for T dwarfs.