TY - JOUR
T1 - JWST and ALMA Multiple-line Study in and around a Galaxy at z = 8.496
T2 - Optical to Far-Infrared Line Ratios and the Onset of an Outflow Promoting Ionizing Photon Escape
AU - Fujimoto, Seiji
AU - Ouchi, Masami
AU - Nakajima, Kimihiko
AU - Harikane, Yuichi
AU - Isobe, Yuki
AU - Brammer, Gabriel
AU - Oguri, Masamune
AU - Giménez-Arteaga, Clara
AU - Heintz, Kasper E.
AU - Kokorev, Vasily
AU - Bauer, Franz E.
AU - Ferrara, Andrea
AU - Kojima, Takashi
AU - Lagos, Claudia del P.
AU - Laura, Sommovigo
AU - Schaerer, Daniel
AU - Shimasaku, Kazuhiro
AU - Hatsukade, Bunyo
AU - Kohno, Kotaro
AU - Sun, Fengwu
AU - Valentino, Francesco
AU - Watson, Darach
AU - Fudamoto, Yoshinobu
AU - Inoue, Akio K.
AU - González-López, Jorge
AU - Koekemoer, Anton M.
AU - Knudsen, Kirsten
AU - Lee, Minju M.
AU - Magdis, Georgios E.
AU - Richard, Johan
AU - Strait, Victoria B.
AU - Sugahara, Yuma
AU - Tamura, Yoichi
AU - Toft, Sune
AU - Umehata, Hideki
AU - Walth, Gregory
N1 - Publisher Copyright:
© 2024. The Author(s). Published by the American Astronomical Society.
PY - 2024/4/1
Y1 - 2024/4/1
N2 - We present Atacama Large Millimeter/submillimeter Array (ALMA) deep spectroscopy for a lensed galaxy at z spec = 8.496 with log ( M star / M ⊙ ) ∼ 7.8 whose optical nebular lines and stellar continuum are detected by JWST/NIRSpec and NIRCam Early Release Observations in the field of SMACS J0723.3-7327. Our ALMA spectrum shows [O iii] 88 μm and [C ii] 158 μm line detections at 4.0σ and 4.5σ, respectively. The redshift and position of the [O iii] line coincide with those of the JWST source, while the [C ii] line is blueshifted by 90 km s−1 with a spatial offset of 0.″5 (≈0.5 kpc in the source plane) from the centroid of the JWST source. The NIRCam F444W image, including [O iii] λ5007 and Hβ line emission, spatially extends beyond the stellar components by a factor of >8. This indicates that the z = 8.5 galaxy has already experienced strong outflows as traced by extended [O iii] λ5007 and offset [C ii] emission, which would promote ionizing photon escape and facilitate reionization. With careful slit-loss corrections and the removal of emission spatially outside the galaxy, we evaluate the [O iii] 88 μm/λ5007 line ratio, and derive the electron density n e by photoionization modeling to be 220 − 130 + 230 cm−3, which is comparable with those of z ∼ 2-3 galaxies. We estimate an [O iii] 88 μm/[C ii] 158 μm line ratio in the galaxy of >4, as high as those of known z ∼ 6-9 galaxies. This high [O iii] 88 μm/[C ii] 158 μm line ratio is generally explained by the high n e as well as the low metallicity ( Z gas / Z ⊙ = 0.04 − 0.02 + 0.02 ), high ionization parameter ( log U > − 2.27 ), and low carbon-to-oxygen abundance ratio (log(C/O) = [−0.52: −0.24]) obtained from the JWST/NIRSpec data; further [C ii] follow-up observations will constrain the covering fraction of photodissociation regions.
AB - We present Atacama Large Millimeter/submillimeter Array (ALMA) deep spectroscopy for a lensed galaxy at z spec = 8.496 with log ( M star / M ⊙ ) ∼ 7.8 whose optical nebular lines and stellar continuum are detected by JWST/NIRSpec and NIRCam Early Release Observations in the field of SMACS J0723.3-7327. Our ALMA spectrum shows [O iii] 88 μm and [C ii] 158 μm line detections at 4.0σ and 4.5σ, respectively. The redshift and position of the [O iii] line coincide with those of the JWST source, while the [C ii] line is blueshifted by 90 km s−1 with a spatial offset of 0.″5 (≈0.5 kpc in the source plane) from the centroid of the JWST source. The NIRCam F444W image, including [O iii] λ5007 and Hβ line emission, spatially extends beyond the stellar components by a factor of >8. This indicates that the z = 8.5 galaxy has already experienced strong outflows as traced by extended [O iii] λ5007 and offset [C ii] emission, which would promote ionizing photon escape and facilitate reionization. With careful slit-loss corrections and the removal of emission spatially outside the galaxy, we evaluate the [O iii] 88 μm/λ5007 line ratio, and derive the electron density n e by photoionization modeling to be 220 − 130 + 230 cm−3, which is comparable with those of z ∼ 2-3 galaxies. We estimate an [O iii] 88 μm/[C ii] 158 μm line ratio in the galaxy of >4, as high as those of known z ∼ 6-9 galaxies. This high [O iii] 88 μm/[C ii] 158 μm line ratio is generally explained by the high n e as well as the low metallicity ( Z gas / Z ⊙ = 0.04 − 0.02 + 0.02 ), high ionization parameter ( log U > − 2.27 ), and low carbon-to-oxygen abundance ratio (log(C/O) = [−0.52: −0.24]) obtained from the JWST/NIRSpec data; further [C ii] follow-up observations will constrain the covering fraction of photodissociation regions.
UR - http://www.scopus.com/inward/record.url?scp=85188945337&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/ad235c
DO - 10.3847/1538-4357/ad235c
M3 - Article
AN - SCOPUS:85188945337
SN - 0004-637X
VL - 964
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 146
ER -