RELATION BETWEEN STELLAR MASS AND STAR-FORMATION ACTIVITY IN GALAXIES
RELATION BETWEEN STELLAR MASS AND STAR-FORMATION ACTIVITY IN GALAXIES
复制标题
星系中恒星质量与恒星形成活动之间的关系
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
K. Sheth
中科院分区：
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作者：
B. Mobasher;T. Dahlén;A. Hopkins;N. Scoville;P. Capak;R. Rich;D. Sanders;E. Schinnerer;O. Ilbert;M. Salvato;K. Sheth
对于来自宇宙演化巡天 (COSMOS) 的 66544 个具有光度红移 (zphot) 星系的质量选择样本，我们研究了恒星形成活动的演化作为星系中恒星质量的函数。我们使用静止框架 2800 Å 通量（针对灭绝进行校正）估计了 0.2 < zphot < 1.2 范围内的宇宙恒星形成速率 (SFR)。我们发现，在任何给定的红移下，平均恒星形成率是银河系恒星质量的强函数，大质量系统（log(M/M☉)>10.5）对总恒星形成率密度（SFRD）的贡献较小（约5倍）。结合来自 COSMOS 和 Gemini Deep Deep Survey 的数据，我们将 SFRD-z 关系作为恒星质量的函数扩展到 z ∼ 2。对于大质量星系，我们发现 SFRD-z 关系相对于 z ∼ 2 急剧增加；对于较小质量的系统，SFRD 也从 z = 0 增加到 1，并在 z ∼ 1 处趋于稳定。这意味着大质量系统在比低质量星系更早的时期 (z > 2) 进行了主要的恒星形成活动。我们研究了不同光谱类型星系的 SFRD 随红移和恒星质量变化的变化。我们发现不同光谱类型星系的 SFRD-z 关系的斜率是其恒星质量的强函数。对于低质量和中等质量的系统，对宇宙 SFRD 的主要贡献来自恒星形成星系，而对于更大质量的系统，演化的星系是最主要的群体。
For a mass-selected sample of 66544 galaxies with photometric redshifts (zphot) from the Cosmic Evolution Survey (COSMOS), we examine the evolution of star-formation activity as a function of stellar mass in galaxies. We estimate the cosmic star-formation rates (SFRs) over the range 0.2 < zphot < 1.2, using the rest-frame 2800 Å flux (corrected for extinction). We find the mean SFR to be a strong function of the galactic stellar mass at any given redshift, with massive systems (log(M/M☉)>10.5) contributing less (by a factor of ∼5) to the total star-formation rate density (SFRD). Combining data from the COSMOS and Gemini Deep Deep Survey, we extend the SFRD–z relation as a function of stellar mass to z ∼ 2. For massive galaxies, we find a steep increase in the SFRD–z relation to z ∼ 2; for the less-massive systems, the SFRD which also increases from z = 0 to 1 levels off at z ∼ 1. This implies that the massive systems have had their major star-formation activity at earlier epochs (z > 2) than the lower-mass galaxies. We study changes in the SFRDs as a function of both redshift and stellar mass for galaxies of different spectral types. We find that the slope of the SFRD–z relation for different spectral types of galaxies is a strong function of their stellar mass. For low- and intermediate-mass systems, the main contribution to the cosmic SFRD comes from the star-forming galaxies while, for more-massive systems, the evolved galaxies are the most dominant population.