Cold brown dwarfs provide unique insights about the low mass terminus of star formation and giant exoplanet atmospheres. However, for the coolest substellar spectral classes (T and Y dwarfs, Teff < 1400 K), little is known about the metallicity dependence of either their atmospheric properties or prevalence. Recently, a new population of cold (Teff < 1400 K), low-metallicity ([M/H] ≤ -1 dex), kinematically extreme brown dwarfs with anomalous spectra has been identified. Limited photometry or spectroscopy exists for this very faint and red sample. Here we present the results of a follow-up near-infrared (YJHK/Ks) photometry campaign using Flamingos-2 at Gemini South and GNIRS at Gemini North, targeting candidate old/cold brown dwarfs. Our deep Gemini photometry allows us to constrain vital physical parameters such as temperature and metallicity, and to prepare/prioritize for future Gemini near-infrared spectroscopy. Particularly in the post-Spitzer era, Gemini represents a crucial follow-up resource for revealing the coldest, lowest metallicity brown dwarfs.

For Zoom connection information, please contact Emanuele Paolo Farina (emanuele.farina_at_noirlab.edu).

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