TY - JOUR

T1 - ALMA Observations of CO Emission from Luminous Lyman-break Galaxies at z=6.0293-6.2037

AU - Ono, Yoshiaki

AU - Fujimoto, Seiji

AU - Harikane, Yuichi

AU - Ouchi, Masami

AU - Vallini, Livia

AU - Ferrara, Andrea

AU - Shibuya, Takatoshi

AU - Pallottini, Andrea

AU - Inoue, Akio K.

AU - Imanishi, Masatoshi

AU - Shimasaku, Kazuhiro

AU - Hashimoto, Takuya

AU - Lee, Chien-Hsiu

AU - Sugahara, Yuma

AU - Tamura, Yoichi

AU - Kohno, Kotaro

AU - Schramm, Malte

PY - 2022/12/1

Y1 - 2022/12/1

N2 - We present our new Atacama Large Millimeter/submillimeter Array (ALMA) observations targeting CO(6-5) emission from three luminous Lyman-break galaxies (LBGs) at z (spec) = 6.0293-6.2037 found in the Subaru/Hyper Suprime-Cam survey, whose [O iii] 88 mu m and [C ii] 158 mu m emissions have been detected with ALMA. We find a marginal detection of the CO(6-5) line from one of our LBGs, J0235-0532, at the similar or equal to 4 sigma significance level and obtain upper limits for the other two LBGs, J1211-0118 and J0217-0208. Our z = 6 luminous LBGs are consistent with the previously found correlation between the CO luminosity and the infrared luminosity. The unique ensemble of the multiple far-infrared emission lines and underlying continuum fed to a photodissociation region model reveals that J0235-0532 has a relatively high density of hydrogen nuclei n (H) that is comparable to those of low-z (U)LIRGs, quasars, and Galactic star-forming regions with high n (H) values, while the other two LBGs have lower n (H) consistent with local star-forming galaxies. By carefully taking account of various uncertainties, we obtain constraints on total gas mass and gas surface density from their CO luminosity measurements. We find that J0235-0532 is located below the Kennicutt-Schmidt (KS) relation, comparable to the z = 5.7 LBG, HZ10, previously detected with CO(2-1). Combined with previous results for dusty starbursts at similar redshifts, the KS relation at z = 5-6 is on average consistent with the local one.

AB - We present our new Atacama Large Millimeter/submillimeter Array (ALMA) observations targeting CO(6-5) emission from three luminous Lyman-break galaxies (LBGs) at z (spec) = 6.0293-6.2037 found in the Subaru/Hyper Suprime-Cam survey, whose [O iii] 88 mu m and [C ii] 158 mu m emissions have been detected with ALMA. We find a marginal detection of the CO(6-5) line from one of our LBGs, J0235-0532, at the similar or equal to 4 sigma significance level and obtain upper limits for the other two LBGs, J1211-0118 and J0217-0208. Our z = 6 luminous LBGs are consistent with the previously found correlation between the CO luminosity and the infrared luminosity. The unique ensemble of the multiple far-infrared emission lines and underlying continuum fed to a photodissociation region model reveals that J0235-0532 has a relatively high density of hydrogen nuclei n (H) that is comparable to those of low-z (U)LIRGs, quasars, and Galactic star-forming regions with high n (H) values, while the other two LBGs have lower n (H) consistent with local star-forming galaxies. By carefully taking account of various uncertainties, we obtain constraints on total gas mass and gas surface density from their CO luminosity measurements. We find that J0235-0532 is located below the Kennicutt-Schmidt (KS) relation, comparable to the z = 5.7 LBG, HZ10, previously detected with CO(2-1). Combined with previous results for dusty starbursts at similar redshifts, the KS relation at z = 5-6 is on average consistent with the local one.

KW - STAR-FORMING GALAXIES

KW - MOLECULAR GAS

KW - HIGH-REDSHIFT

KW - II EMISSION

KW - HOST GALAXY

KW - SUBMILLIMETER EMISSION

KW - RAPID TRANSITION

KW - NEARBY GALAXIES

KW - DEPLETION TIME

KW - LINE EMISSION

U2 - 10.3847/1538-4357/ac9ea6

DO - 10.3847/1538-4357/ac9ea6

M3 - Journal article

VL - 941

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 74

ER -