Early Results from GLASS-JWST. XXI: Rapid assembly of a galaxy at z=6.23 revealed by its C/O abundance

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Tucker Jones Ryan Sanders Yuguang Chen Xin Wang Takahiro Morishita Guido Roberts-Borsani Tommaso Treu Alan Dressler Emiliano Merlin Diego Paris Paola Santini Pietro Bergamini Erin Huntzinger Themiya Nanayakkara Kristan Boyett Marusa Bradac Gabriel Brammer Antonello Calabro Karl Glazebrook Kathryn Grasha

摘要： The abundance of carbon relative to oxygen (C/O) is a promising probe of star formation history in the early universe, as these elements are produced on different timescales. We present a measurement of $\log{\mathrm{(C/O)}} = -1.01\pm0.12$ (stat) $\pm0.10$ (sys) in a $z=6.23$ galaxy observed as part of the GLASS-JWST Early Release Science Program. Notably, we achieve good precision thanks to the detection of the rest-frame ultraviolet O III], C III], and C IV emission lines delivered by JWST/NIRSpec. The C/O abundance is $\sim$0.8 dex lower than the solar value and is consistent with the expected yield from core-collapse supernovae, indicating negligible carbon enrichment from intermediate-mass stars. This in turn implies rapid buildup of a young stellar population with age $\lesssim$100 Myr in a galaxy seen $\sim$900 million years after the Big Bang. Our chemical abundance analysis is consistent with spectral energy distribution modeling of JWST/NIRCam photometric data, which indicates a current stellar mass $\log\,\mathrm{M}_* / \mathrm{Msun} = 8.4^{+0.4}_{-0.2}$ and specific star formation rate sSFR $\simeq 20$ Gyr$^{-1}$. These results showcase the value of chemical abundances and C/O in particular to study the earliest stages of galaxy assembly.

同行评议状态:待评议

 点击量 35  下载量 31  评论