Galaxy And Mass Assembly (GAMA): Linking Star Formation Histories and Stellar Mass Growth
Galaxy And Mass Assembly (GAMA): Linking Star Formation Histories and Stellar Mass Growth
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DOI：
10.1093/mnras/stt1011
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发表时间：
2013-06
影响因子：
4.8
通讯作者：
A. Bauer;A. Hopkins;M. Gunawardhana;E. Taylor;E. Taylor;I. Baldry;S. Bamford;J. Bland-Hawthorn;S. Brough;Michael J. I. Brown;M. Cluver;M. Colless;M. Colless;C. Conselice;S. Croom;S. Driver;S. Driver;C. Foster;D. Jones;M. Lara-López;J. Liske;Á. López-Sánchez;Á. López-Sánchez;J. Loveday;P. Norberg;M. Owers;K. Pimbblet;A. Robotham;A. Robotham;A. Sansom;R. Sharp
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文献类型：
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作者：
A. Bauer;A. Hopkins;M. Gunawardhana;E. Taylor;E. Taylor;I. Baldry;S. Bamford;J. Bland-Hawthorn;S. Brough;Michael J. I. Brown;M. Cluver;M. Colless;M. Colless;C. Conselice;S. Croom;S. Driver;S. Driver;C. Foster;D. Jones;M. Lara-López;J. Liske;Á. López-Sánchez;Á. López-Sánchez;J. Loveday;P. Norberg;M. Owers;K. Pimbblet;A. Robotham;A. Robotham;A. Sansom;R. Sharp
我们目前的证据随机星星形成的历史，在低质量（M* < 1010 M <$）星系的观测范围内的星系和质量大会（GAMA）的调查。对于0.05 < z < 0.32的173000个星系，我们利用光谱Hα测量值计算了星星形成率（SFR）和比星星形成率（SSFR = SFR/M*），并应用了由Balmer减量导出的尘埃修正。我们发现SSFR对恒星质量的依赖性，使得SSFR随着恒星质量的增加而降低，对于完整的样本，SSFR随着恒星质量的增加而降低。我们使用简单的参数化指数下降的星星形成的历史调查的星星形成时间尺度和形成红移的恒星质量的依赖。我们发现，参数化以前适合的z-11星系的样本不能恢复在0.05 < z < 0.32之间的GAMA样本中观察到的SSFR和恒星质量的分布。特别是，大量的低质量（M* < 1010 M）星系被观察到具有比这些简单模型在0.05 < z < 0.32的红移范围内所能解释的高得多的SSFR，即使在调用质量依赖的阶段演化时也是如此。对于这样一个大量的星系，以保持低恒星质量，但港口如此高的SSFR，需要一个弱的潜在指数下降的星星形成历史的叠加随机爆发的星星形成晚发病。
We present evidence for stochastic star formation histories in low-mass (M* < 1010 M⊙) galaxies from observations within the Galaxy And Mass Assembly (GAMA) survey. For ˜73 000 galaxies between 0.05 < z < 0.32, we calculate star formation rates (SFR) and specific star formation rates (SSFR = SFR/M*) from spectroscopic Hα measurements and apply dust corrections derived from Balmer decrements. We find a dependence of SSFR on stellar mass, such that SSFRs decrease with increasing stellar mass for star-forming galaxies, and for the full sample, SSFRs decrease as a stronger function of stellar mass. We use simple parametrizations of exponentially declining star formation histories to investigate the dependence on stellar mass of the star formation time-scale and the formation redshift. We find that parametrizations previously fit to samples of z ˜ 1 galaxies cannot recover the distributions of SSFRs and stellar masses observed in the GAMA sample between 0.05 < z < 0.32. In particular, a large number of low-mass (M* < 1010 M⊙) galaxies are observed to have much higher SSFRs than can be explained by these simple models over the redshift range of 0.05 < z < 0.32, even when invoking mass-dependent staged evolution. For such a large number of galaxies to maintain low stellar masses, yet harbour such high SSFRs, requires the late onset of a weak underlying exponentially declining star formation history with stochastic bursts of star formation superimposed.