High Molecular Gas Masses in Absorption-selected Galaxies at z approximate to 2
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High Molecular Gas Masses in Absorption-selected Galaxies at z approximate to 2. / Kanekar, N.; Prochaska, J. X.; Neeleman, M.; Christensen, L.; Moller, P.; Zwaan, M. A.; Fynbo, J. P. U.; Dessauges-Zavadsky, M.
In: Astrophysical Journal Letters, Vol. 901, No. 1, 5, 20.09.2020.Research output: Contribution to journal › Letter › Research › peer-review
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T1 - High Molecular Gas Masses in Absorption-selected Galaxies at z approximate to 2
AU - Kanekar, N.
AU - Prochaska, J. X.
AU - Neeleman, M.
AU - Christensen, L.
AU - Moller, P.
AU - Zwaan, M. A.
AU - Fynbo, J. P. U.
AU - Dessauges-Zavadsky, M.
PY - 2020/9/20
Y1 - 2020/9/20
N2 - We have used the Atacama Large Millimeter/submillimeter Array (ALMA) to carry out a search for CO (3-2) or (4-3) emission from the fields of 12 high-metallicity ([M/H]...-0.72 dex) damped Lya absorbers (DLAs) at z approximate to 1.7-2.6. We detected CO emission from galaxies in the fields of five DLAs (two of which have been reported earlier), obtaining high molecular gas masses, M-mol approximate to (1.3-20.7) x (alpha C-O/4.36) x 10(10) M-circle dot. The impact parameters of the CO emitters to the QSO sight line lie in the range b similar to 5.6-100 kpc, with the three new CO detections having b less than or similar to 15 kpc. The highest CO line luminosities and inferred molecular gas masses are associated with the highest-metallicity DLAs, with [M/H] greater than or similar to -0.3 dex. The high inferred molecular gas masses may be explained by a combination of a stellar mass-metallicity relation and a high molecular gas-to-star mass ratio in high-redshift galaxies; the DLA galaxies identified by our CO searches have properties consistent with those of emission-selected samples. None of the DLA galaxies detected in CO emission were identified in earlier optical or near-IR searches and vice versa; DLA galaxies earlier identified in optical/near-IR searches were not detected in CO emission. The high ALMA CO and C[II] 158 mu m detection rate in high-z, high-metallicity DLA galaxies has revolutionized the field, allowing the identification of dusty, massive galaxies associated with high-z DLAs. The H I-absorption criterion identifying DLAs selects the entire high-z galaxy population, including dusty and UVbright galaxies, in a wide range of environments.
AB - We have used the Atacama Large Millimeter/submillimeter Array (ALMA) to carry out a search for CO (3-2) or (4-3) emission from the fields of 12 high-metallicity ([M/H]...-0.72 dex) damped Lya absorbers (DLAs) at z approximate to 1.7-2.6. We detected CO emission from galaxies in the fields of five DLAs (two of which have been reported earlier), obtaining high molecular gas masses, M-mol approximate to (1.3-20.7) x (alpha C-O/4.36) x 10(10) M-circle dot. The impact parameters of the CO emitters to the QSO sight line lie in the range b similar to 5.6-100 kpc, with the three new CO detections having b less than or similar to 15 kpc. The highest CO line luminosities and inferred molecular gas masses are associated with the highest-metallicity DLAs, with [M/H] greater than or similar to -0.3 dex. The high inferred molecular gas masses may be explained by a combination of a stellar mass-metallicity relation and a high molecular gas-to-star mass ratio in high-redshift galaxies; the DLA galaxies identified by our CO searches have properties consistent with those of emission-selected samples. None of the DLA galaxies detected in CO emission were identified in earlier optical or near-IR searches and vice versa; DLA galaxies earlier identified in optical/near-IR searches were not detected in CO emission. The high ALMA CO and C[II] 158 mu m detection rate in high-z, high-metallicity DLA galaxies has revolutionized the field, allowing the identification of dusty, massive galaxies associated with high-z DLAs. The H I-absorption criterion identifying DLAs selects the entire high-z galaxy population, including dusty and UVbright galaxies, in a wide range of environments.
KW - High-redshift galaxies
KW - Damped Lyman-alpha systems
KW - Molecular gas
KW - LY-ALPHA SYSTEMS
KW - DAMPED LYMAN
KW - METALLICITY RELATION
KW - METAL-RICH
KW - BILLION YEARS
KW - CO EMISSION
KW - ABSORBER
KW - MUSE
KW - DLA
U2 - 10.3847/2041-8213/abb4e1
DO - 10.3847/2041-8213/abb4e1
M3 - Letter
VL - 901
JO - The Astrophysical Journal Letters
JF - The Astrophysical Journal Letters
SN - 2041-8205
IS - 1
M1 - 5
ER -
ID: 249905240