PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS IN z ∼ 1–3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES
PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS IN z ∼ 1–3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES
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DOI：
10.1088/0004-637x/768/1/74
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发表时间：
2012-11
期刊：
影响因子：
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通讯作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
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文献类型：
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作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
我们提出了PHIBSS， IRAM高原de Bure高z蓝色序列CO 3-2对靠近宇宙恒星形成高峰的大质量主序恒星形成星系（SFGs）的分子气体特性的调查。PHIBSS在z ~ 1.2和2.2的两个红移切片中提供52个CO检测，log（M*（M☉））大于或等于10.4,log（SFR(M☉/yr)）大于或等于1.5。包括对M* -SFR平面不完全覆盖的修正，并采用“银河”值作为CO-H2转换因子，我们推断z ~ 1.2和z ~ 2.2的平均气体馏分分别为~ 0.33和~ 0.47。气体分数随着恒星质量的下降而下降，这与包括强恒星形成反馈在内的宇宙学模拟结果一致。大多数z ~ 1-3 sfg是旋转支撑的湍流盘。CO和UV/光学发射的大小是相当的。z = 1-3个SFGs的分子-气体-恒星形成关系是近线性的，具有~ 0.7 Gyr的气体耗尽时间尺度；消耗时间的变化只是次要影响。由于在z ~ 0和2之间的所有SFGs中，这个时间尺度远小于哈勃时间，因此在几十亿年的时间里，新鲜气体必须以相当高的占空比供应。在给定的z和M*下，气体组分与特定恒星形成速率（sSFR）密切相关。sSFR在z ~ 0 ~ 3之间的变化主要受低温气体中重子质量的影响。
We present PHIBSS, the IRAM Plateau de Bure high-z blue sequence CO 3–2 survey of the molecular gas properties in massive, main-sequence star-forming galaxies (SFGs) near the cosmic star formation peak. PHIBSS provides 52 CO detections in two redshift slices at z ∼ 1.2 and 2.2, with log(M*(M☉)) ⩾ 10.4 and log(SFR(M☉/yr)) ⩾ 1.5. Including a correction for the incomplete coverage of the M*–SFR plane, and adopting a “Galactic” value for the CO–H2 conversion factor, we infer average gas fractions of ∼0.33 at z ∼ 1.2 and ∼0.47 at z ∼ 2.2. Gas fractions drop with stellar mass, in agreement with cosmological simulations including strong star formation feedback. Most of the z ∼ 1–3 SFGs are rotationally supported turbulent disks. The sizes of CO and UV/optical emission are comparable. The molecular-gas–star-formation relation for the z = 1–3 SFGs is near-linear, with a ∼0.7 Gyr gas depletion timescale; changes in depletion time are only a secondary effect. Since this timescale is much less than the Hubble time in all SFGs between z ∼ 0 and 2, fresh gas must be supplied with a fairly high duty cycle over several billion years. At given z and M*, gas fractions correlate strongly with the specific star formation rate (sSFR). The variation of sSFR between z ∼ 0 and 3 is mainly controlled by the fraction of baryonic mass that resides in cold gas.