Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations
We report the spectroscopic identification of three brown dwarf candidates—o005_s41280, o006_s00089, and o006_s35616—discovered in RUBIES using James Webb Space Telescope (JWST) Near-Infrared Spectrograph PRISM/CLEAR spectroscopy. We fit these sources with multiple substellar atmosphere models and p...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adaf9f |
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| author | Zhijun Tu Shu Wang Xiaodian Chen Jifeng Liu |
| author_facet | Zhijun Tu Shu Wang Xiaodian Chen Jifeng Liu |
| author_sort | Zhijun Tu |
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| description | We report the spectroscopic identification of three brown dwarf candidates—o005_s41280, o006_s00089, and o006_s35616—discovered in RUBIES using James Webb Space Telescope (JWST) Near-Infrared Spectrograph PRISM/CLEAR spectroscopy. We fit these sources with multiple substellar atmosphere models and present the atmospheric parameters, including effective temperature ( T _eff ), surface gravity, and other derived properties. The results suggest that o005_s41280 and o006_s35616, with T _eff in the ranges of 2100–2300 K and 1800–2000 K, respectively, are likely L dwarfs, while o006_s00089, with T _eff < 1000 K, is consistent with a late T dwarf classification. The best-fit model spectra provide a reasonable match to the observed spectra. However, distinct residuals exist in the Y , J , and H bands for the two L dwarf candidates, particularly for o006_s35616. Incorporating the extinction parameter into the fitting process can significantly reduce these residuals. The distance estimates indicate that these candidates are about 2 kpc away. The analysis of the color–color diagram using multiple JWST NIRcam photometry suggests that cooler T dwarfs, such as o006_s00089, overlap with little red dots, while hotter L dwarfs, like o005_s41280 and o006_s35616, tend to contaminate the high-redshift galaxy cluster. These findings suggest a brown dwarf contamination rate of approximately 0.1% in extragalactic deep field surveys, with L dwarfs being more frequently detected than cooler T and Y dwarfs. |
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| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-2abd964a468c44e181bd7962469b1ca92025-08-20T02:43:49ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01980223010.3847/1538-4357/adaf9fThree Brown Dwarfs Masquerading as High-redshift Galaxies in JWST ObservationsZhijun Tu0https://orcid.org/0009-0000-7976-7383Shu Wang1https://orcid.org/0000-0003-4489-9794Xiaodian Chen2https://orcid.org/0000-0001-7084-0484Jifeng Liu3CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; shuwang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; shuwang@nao.cas.cnCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; shuwang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of China; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; shuwang@nao.cas.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of China; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of China; New Cornerstone Science Laboratory, National Astronomical Observatories , Chinese Academy of Sciences, Beijing 100012, People’s Republic of ChinaWe report the spectroscopic identification of three brown dwarf candidates—o005_s41280, o006_s00089, and o006_s35616—discovered in RUBIES using James Webb Space Telescope (JWST) Near-Infrared Spectrograph PRISM/CLEAR spectroscopy. We fit these sources with multiple substellar atmosphere models and present the atmospheric parameters, including effective temperature ( T _eff ), surface gravity, and other derived properties. The results suggest that o005_s41280 and o006_s35616, with T _eff in the ranges of 2100–2300 K and 1800–2000 K, respectively, are likely L dwarfs, while o006_s00089, with T _eff < 1000 K, is consistent with a late T dwarf classification. The best-fit model spectra provide a reasonable match to the observed spectra. However, distinct residuals exist in the Y , J , and H bands for the two L dwarf candidates, particularly for o006_s35616. Incorporating the extinction parameter into the fitting process can significantly reduce these residuals. The distance estimates indicate that these candidates are about 2 kpc away. The analysis of the color–color diagram using multiple JWST NIRcam photometry suggests that cooler T dwarfs, such as o006_s00089, overlap with little red dots, while hotter L dwarfs, like o005_s41280 and o006_s35616, tend to contaminate the high-redshift galaxy cluster. These findings suggest a brown dwarf contamination rate of approximately 0.1% in extragalactic deep field surveys, with L dwarfs being more frequently detected than cooler T and Y dwarfs.https://doi.org/10.3847/1538-4357/adaf9fBrown dwarfsL dwarfsT dwarfsStellar atmospheresHigh-redshift galaxies |
| spellingShingle | Zhijun Tu Shu Wang Xiaodian Chen Jifeng Liu Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations The Astrophysical Journal Brown dwarfs L dwarfs T dwarfs Stellar atmospheres High-redshift galaxies |
| title | Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations |
| title_full | Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations |
| title_fullStr | Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations |
| title_full_unstemmed | Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations |
| title_short | Three Brown Dwarfs Masquerading as High-redshift Galaxies in JWST Observations |
| title_sort | three brown dwarfs masquerading as high redshift galaxies in jwst observations |
| topic | Brown dwarfs L dwarfs T dwarfs Stellar atmospheres High-redshift galaxies |
| url | https://doi.org/10.3847/1538-4357/adaf9f |
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