Substellar and low-mass dwarf identification with near-infrared imaging space observatories
Aims. We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope. Methods. We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the M-, L-, and T-type dwarfs. We have identified which color–color combination is optimal for identifying broad type and which single color is optimal to then identify the subtype (e.g., T0-9). We evaluated each observatory separately as well as the narrow-field (HST and JWST) and wide-field (Euclid and WFIRST) combinations. Results. The Euclid filters perform equally well as HST wide filters in discriminating between broad types of brown dwarfs. WFIRST performs similarly well, despite a wider selection of filters. However, subtyping with any combination of Euclid and WFIRST observations remains uncertain due to the lack of medium, or narrow-band filters. We argue that a medium band added to the WFIRST filter selection would greatly improve its ability to preselect brown dwarfs its imaging surveys. Conclusions. The HST filters used in high-redshift searches are close to optimal to identify broad stellar type. However, the addition of F127M to the commonly used broad filter sets would allow for unambiguous subtyping. An improvement over HST is one of two broad and medium filter combinations on JWST: pairing F140M with either F150W or F162M discriminates very well between subtypes.
Additional Information© ESO 2018. Received 15 February 2018 / Accepted 09 April 2018. The authors would like to thank the anonymous referee for the constructive and thoughtful critique of the earlier draft. This research made use of ASTROPY, a community developed core Python package for Astronomy (Astropy Collaboration 2013). This research made use of MATPLOTLIB, a Python library for publication quality graphics (Hunter 2007). PYRAF is a product of the Space Telescope Science Institute, which is operated by AURA for NASA. This research made use of both SCIPY (Jones et al. 2001) and SPLAT (Burgasser & SPLAT Development Team 2017). SPLAT is an experimental, collaborative project of research students in Adam Burgasser's UCSD Cool Star Lab, aimed at teaching students how to do research by building their own analysis tools. Contributors to SPLAT have included Christian Aganze, Jessica Birky, Daniella Bardalez Gagliuffi, Adam Burgasser (PI), Caleb Choban, Andrew Davis, Ivanna Escala, Aishwarya Iyer, Yuhui Jin, Mike Lopez, Alex Mendez, Gretel Mercado, Elizabeth Moreno Hilario, Johnny Parra, Maitrayee Sahi, Adrian Suarez, Melisa Tallis, Tomoki Tamiya, Chris Theissen, and Russell van Linge. This project is supported by the National Aeronautics and Space Administration under Grant No. NNX15AI75G.
Published - aa32838-18.pdf
Accepted Version - 1805.00997.pdf