TY - JOUR
T1 - First Peek with JWST/NIRCam Wide-field Slitless Spectroscopy
T2 - Serendipitous Discovery of a Strong [O iii]/H α Emitter at z = 6.11
AU - Sun, Fengwu
AU - Egami, Eiichi
AU - Pirzkal, Nor
AU - Rieke, Marcia
AU - Boyer, Martha
AU - Correnti, Matteo
AU - Gennaro, Mario
AU - Girard, Julien
AU - Greene, Thomas P.
AU - Kelly, Doug
AU - Koekemoer, Anton M.
AU - Leisenring, Jarron
AU - Misselt, Karl
AU - Nikolov, Nikolay
AU - Roellig, Thomas L.
AU - Stansberry, John
AU - Williams, Christina C.
AU - Willmer, Christopher N.A.
N1 - Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/9/1
Y1 - 2022/9/1
N2 - We report the serendipitous discovery of an [O iii] λ λ4959/5007 and Hα line emitter in the Epoch of Reionization (EoR) with the James Webb Space Telescope (JWST) commissioning data taken in the NIRCam wide-field slitless spectroscopy (WFSS) mode. Located 1/455″ away from the flux calibrator P330-E, this galaxy exhibits bright [O iii] λ λ4959/5007 and Hα lines detected at 3.7σ, 9.9σ, and 5.7σ, respectively, with a spectroscopic redshift of z = 6.112 ± 0.001. The total Hβ+[O iii] equivalent width is 664 ± 98 Å (454 ± 78 Å from the [O iii] λ5007 line). This provides direct spectroscopic evidence for the presence of strong rest-frame optical lines (Hβ+[O iii] and Hα) in EoR galaxies as inferred previously from the analyses of the Spitzer/IRAC spectral energy distributions (SEDs). Two spatial and velocity components are identified in this source, possibly indicating that this system is undergoing a major merger, which might have triggered the ongoing starburst with strong nebular emission lines over a timescale of 1/42 Myr, as our SED modeling suggests. The tentative detection of He ii λ4686 line (1.9σ), if real, may indicate the existence of very young and metal-poor star-forming regions with a hard UV radiation field. Finally, this discovery demonstrates the power and readiness of the JWST/NIRCam WFSS mode, and marks the beginning of a new era for extragalactic astronomy, in which EoR galaxies can be routinely discovered via blind slitless spectroscopy through the detection of rest-frame optical emission lines.
AB - We report the serendipitous discovery of an [O iii] λ λ4959/5007 and Hα line emitter in the Epoch of Reionization (EoR) with the James Webb Space Telescope (JWST) commissioning data taken in the NIRCam wide-field slitless spectroscopy (WFSS) mode. Located 1/455″ away from the flux calibrator P330-E, this galaxy exhibits bright [O iii] λ λ4959/5007 and Hα lines detected at 3.7σ, 9.9σ, and 5.7σ, respectively, with a spectroscopic redshift of z = 6.112 ± 0.001. The total Hβ+[O iii] equivalent width is 664 ± 98 Å (454 ± 78 Å from the [O iii] λ5007 line). This provides direct spectroscopic evidence for the presence of strong rest-frame optical lines (Hβ+[O iii] and Hα) in EoR galaxies as inferred previously from the analyses of the Spitzer/IRAC spectral energy distributions (SEDs). Two spatial and velocity components are identified in this source, possibly indicating that this system is undergoing a major merger, which might have triggered the ongoing starburst with strong nebular emission lines over a timescale of 1/42 Myr, as our SED modeling suggests. The tentative detection of He ii λ4686 line (1.9σ), if real, may indicate the existence of very young and metal-poor star-forming regions with a hard UV radiation field. Finally, this discovery demonstrates the power and readiness of the JWST/NIRCam WFSS mode, and marks the beginning of a new era for extragalactic astronomy, in which EoR galaxies can be routinely discovered via blind slitless spectroscopy through the detection of rest-frame optical emission lines.
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U2 - 10.3847/2041-8213/ac8938
DO - 10.3847/2041-8213/ac8938
M3 - Article
AN - SCOPUS:85137691834
SN - 2041-8205
VL - 936
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L8
ER -