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Early Results from GLASS-JWST. XIII. A Faint, Distant, and Cold Brown Dwarf

Nonino, Mario and Glazebrook, Karl and Burgasser, Adam J. and Polenta, Gianluca and Morishita, Takahiro and Lepinzan, Marius and Castellano, Marco and Fontana, Adriano and Merlin, Emiliano and Bonchi, Andrea and Paris, Diego and Treu, Tommaso and Vulcani, Benedetta and Wang, Xin and Santini, Paola and Vanzella, Eros and Nanayakkara, Themiya and Mercurio, Amata and Rosati, Piero and Grillo, Claudio and Bradac, Marusa (2023) Early Results from GLASS-JWST. XIII. A Faint, Distant, and Cold Brown Dwarf. Astrophysical Journal Letters, 942 (2). Art. No. L29. ISSN 2041-8205. doi:10.3847/2041-8213/ac8e5f.

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We present the serendipitous discovery of a late T-type brown dwarf candidate in JWST NIRCam observations of the Early Release Science Abell 2744 parallel field. The discovery was enabled by the sensitivity of JWST at 4 μm wavelengths and the panchromatic 0.9–4.5 μm coverage of the spectral energy distribution. The unresolved point source has magnitudes F115W = 27.95 ± 0.15 and F444W = 25.84 ± 0.01 (AB), and its F115W−F444W and F356W−F444W colors match those expected for other known T dwarfs. We can exclude it as a reddened background star, high redshift quasar, or a very high redshift galaxy. Comparison with stellar atmospheric models indicates a temperature of T_(eff) ≈ 650 K and surface gravity log g ≈ 5.25, implying a mass of 0.03 M_⊙ and age of 5 Gyr. We estimate the distance of this candidate to be 570–720 pc in a direction perpendicular to the Galactic plane, making it a likely thick disk or halo brown dwarf. These observations underscore the power of JWST to probe the very low-mass end of the substellar mass function in the Galactic thick disk and halo.

Item Type:Article
Related URLs:
URLURL TypeDescription
Nonino, Mario0000-0001-6342-9662
Glazebrook, Karl0000-0002-3254-9044
Burgasser, Adam J.0000-0002-6523-9536
Polenta, Gianluca0000-0003-4067-9196
Morishita, Takahiro0000-0002-8512-1404
Lepinzan, Marius0000-0003-1287-9801
Castellano, Marco0000-0001-9875-8263
Fontana, Adriano0000-0003-3820-2823
Merlin, Emiliano0000-0001-6870-8900
Bonchi, Andrea0000-0002-2667-5482
Paris, Diego0000-0002-7409-8114
Treu, Tommaso0000-0002-8460-0390
Vulcani, Benedetta0000-0003-0980-1499
Wang, Xin0000-0002-9373-3865
Santini, Paola0000-0002-9334-8705
Vanzella, Eros0000-0002-5057-135X
Nanayakkara, Themiya0000-0003-2804-0648
Mercurio, Amata0000-0001-9261-7849
Rosati, Piero0000-0002-6813-0632
Grillo, Claudio0000-0002-5926-7143
Bradac, Marusa0000-0001-5984-0395
Additional Information:Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program JWST-ERS-1324. We acknowledge financial support from NASA through grant JWST-ERS-1324. K.G. and T.N. acknowledge support from Australian Research Council Laureate Fellowship FL180100060. We acknowledge financial support through grants PRIN-MIUR 2017WSCC32, PRIN-MIUR 2020SKSTHZ, and INAF-Mainstreams M.B. acknowledges support by the Slovenian national research agency ARRS through grant N1-0238. Facilities: JWST (NIRCam imaging). Software: gsf (Morishita et al. 2019), SPLAT (Burgasser 2017), ds9 (Smithsonian Astrophysical Observatory 2000), R (R Core Team 2020).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASANAS 5-03127
Australian Research CouncilFL180100060
Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR)2017WSCC32
Ministero dell'Istruzione, dell'Universitá e della Ricerca (MIUR)2020SKSTHZ
Istituto Nazionale di Astrofisica (INAF)
Slovenian Research Agency (ARRS)N1-0238
Issue or Number:2
Record Number:CaltechAUTHORS:20230209-988069100.8
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:119174
Deposited By: Research Services Depository
Deposited On:15 Mar 2023 16:52
Last Modified:15 Mar 2023 16:52

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