Ken-ichi Tadaki, Tadayuki Kodama, Yusei Koyama, Tomoko L. Suzuki, Ikki Mitsuhashi, Ryota Ikeda
{"title":"用ALMA和JWST测定z ~ 2.2-2.5大质量星系中分子气体、尘埃和恒星的空间范围","authors":"Ken-ichi Tadaki, Tadayuki Kodama, Yusei Koyama, Tomoko L. Suzuki, Ikki Mitsuhashi, Ryota Ikeda","doi":"10.3847/2041-8213/ad03f2","DOIUrl":null,"url":null,"abstract":"Abstract We present the results of 0.″6-resolution observations of CO J = 3 − 2 line emission in 10 massive star-forming galaxies at z ∼ 2.2–2.5 with the Atacama Large Millimeter/submillimeter Array (ALMA). We compare the spatial extent of molecular gas with those of dust and stars, traced by the 870 and 4.4 μ m continuum emissions, respectively. The average effective radius of the CO emission is 1.75 ± 0.34 kpc, which is about 60% larger than that of the 870 μ m emission and is comparable with that of the 4.4 μ m emission. Utilizing the best-fit parametric models, we derive the radial gradients of the specific star formation rate (sSFR), gas depletion timescale, and gas-mass fraction within the observed galaxies. We find a more intense star formation activity with a higher sSFR and a shorter depletion timescale in the inner region than in the outer region. The central starburst may be the primary process for massive galaxies to build up a core. Furthermore, the gas-mass fraction is high, independent of the galactocentric radius in the observed galaxies, suggesting that the galaxies have not begun to quench star formation. Given the shorter gas depletion timescale in the center compared to the outer region, quenching is expected to occur in the center first and then propagate outward. We may be witnessing the observed galaxies in the formation phase of a core prior to the forthcoming phase of star formation propagating outward.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"23 17","pages":"0"},"PeriodicalIF":8.8000,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Spatial Extent of Molecular Gas, Dust, and Stars in Massive Galaxies at z ∼ 2.2–2.5 Determined with ALMA and JWST\",\"authors\":\"Ken-ichi Tadaki, Tadayuki Kodama, Yusei Koyama, Tomoko L. Suzuki, Ikki Mitsuhashi, Ryota Ikeda\",\"doi\":\"10.3847/2041-8213/ad03f2\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract We present the results of 0.″6-resolution observations of CO J = 3 − 2 line emission in 10 massive star-forming galaxies at z ∼ 2.2–2.5 with the Atacama Large Millimeter/submillimeter Array (ALMA). We compare the spatial extent of molecular gas with those of dust and stars, traced by the 870 and 4.4 μ m continuum emissions, respectively. The average effective radius of the CO emission is 1.75 ± 0.34 kpc, which is about 60% larger than that of the 870 μ m emission and is comparable with that of the 4.4 μ m emission. Utilizing the best-fit parametric models, we derive the radial gradients of the specific star formation rate (sSFR), gas depletion timescale, and gas-mass fraction within the observed galaxies. We find a more intense star formation activity with a higher sSFR and a shorter depletion timescale in the inner region than in the outer region. The central starburst may be the primary process for massive galaxies to build up a core. Furthermore, the gas-mass fraction is high, independent of the galactocentric radius in the observed galaxies, suggesting that the galaxies have not begun to quench star formation. Given the shorter gas depletion timescale in the center compared to the outer region, quenching is expected to occur in the center first and then propagate outward. We may be witnessing the observed galaxies in the formation phase of a core prior to the forthcoming phase of star formation propagating outward.\",\"PeriodicalId\":55567,\"journal\":{\"name\":\"Astrophysical Journal Letters\",\"volume\":\"23 17\",\"pages\":\"0\"},\"PeriodicalIF\":8.8000,\"publicationDate\":\"2023-11-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Astrophysical Journal Letters\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.3847/2041-8213/ad03f2\",\"RegionNum\":1,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysical Journal Letters","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3847/2041-8213/ad03f2","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
Spatial Extent of Molecular Gas, Dust, and Stars in Massive Galaxies at z ∼ 2.2–2.5 Determined with ALMA and JWST
Abstract We present the results of 0.″6-resolution observations of CO J = 3 − 2 line emission in 10 massive star-forming galaxies at z ∼ 2.2–2.5 with the Atacama Large Millimeter/submillimeter Array (ALMA). We compare the spatial extent of molecular gas with those of dust and stars, traced by the 870 and 4.4 μ m continuum emissions, respectively. The average effective radius of the CO emission is 1.75 ± 0.34 kpc, which is about 60% larger than that of the 870 μ m emission and is comparable with that of the 4.4 μ m emission. Utilizing the best-fit parametric models, we derive the radial gradients of the specific star formation rate (sSFR), gas depletion timescale, and gas-mass fraction within the observed galaxies. We find a more intense star formation activity with a higher sSFR and a shorter depletion timescale in the inner region than in the outer region. The central starburst may be the primary process for massive galaxies to build up a core. Furthermore, the gas-mass fraction is high, independent of the galactocentric radius in the observed galaxies, suggesting that the galaxies have not begun to quench star formation. Given the shorter gas depletion timescale in the center compared to the outer region, quenching is expected to occur in the center first and then propagate outward. We may be witnessing the observed galaxies in the formation phase of a core prior to the forthcoming phase of star formation propagating outward.
期刊介绍:
The Astrophysical Journal Letters (ApJL) is widely regarded as the foremost journal for swiftly disseminating groundbreaking astronomical research. It focuses on concise reports that highlight pivotal advancements in the field of astrophysics. By prioritizing timeliness and the generation of immediate interest among researchers, ApJL showcases articles featuring novel discoveries and critical findings that have a profound effect on the scientific community. Moreover, ApJL ensures that published articles are comprehensive in their scope, presenting context that can be readily comprehensible to scientists who may not possess expertise in the specific disciplines covered.