GALAXY STELLAR MASS FUNCTIONS FROM ZFOURGE/CANDELS: AN EXCESS OF LOW-MASS GALAXIES SINCE z = 2 AND THE RAPID BUILDUP OF QUIESCENT GALAXIES
GALAXY STELLAR MASS FUNCTIONS FROM ZFOURGE/CANDELS: AN EXCESS OF LOW-MASS GALAXIES SINCE z = 2 AND THE RAPID BUILDUP OF QUIESCENT GALAXIES
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DOI：
10.1088/0004-637x/783/2/85
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发表时间：
2013-09
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影响因子：
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通讯作者：
A. Tomczak;R. Quadri;K. Tran;I. Labbé;C. Straatman;Casey;Papovich;K. Glazebrook;R. Allen
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作者：
A. Tomczak;R. Quadri;K. Tran;I. Labbé;C. Straatman;Casey;Papovich;K. Glazebrook;R. Allen
利用FourStar Galaxy Evolution Survey（ZFOURGE）的观测结果，我们获得了迄今为止最深的星系恒星质量函数（SMF）的测量结果。ZFOURGE通过1-2 μm的深中带宽成像提供了良好约束的光度红移。我们联合收割机将其与来自宇宙组装近红外深河外遗产巡天的哈勃太空望远镜成像相结合，从而可以有效地选择蓝色和红色星系，直到z = 2.5的恒星质量为109.5 M。总调查面积为316弧分2，分布在三个独立的领域。我们补充这些数据与更广泛和更浅的NEWFIRM中频调查，以提供更强的约束在高质量。在z = 1.5处的几项研究表明，SMF的低质量端的斜率变陡，导致质量<1010 M时的上升，这不能用标准的单谢赫特函数很好地描述。我们发现的证据表明，这一功能延伸到至少z 102，它可以在两个恒星形成和静止的人口单独发现。与SMF拟合的双谢克特函数的特征质量（M*）和最低质量（α）的斜率大致保持不变，分别为Log（M/M反馈）<$10.65和<$− 1.5。恒星形成星系的SMF主要在标准化中演化，而形状的变化相对较小。我们的数据使我们能够，第一次，观察到一个快速的建立在低质量端的静态SMF。由于z = 2.5，静止星系的总质量密度（低至109 M）增加了1.12倍，而恒星形成星系的质量密度只增加了1.22倍。
Using observations from the FourStar Galaxy Evolution Survey (ZFOURGE), we obtain the deepest measurements to date of the galaxy stellar mass function (SMF) at 0.2 < z < 3. ZFOURGE provides well-constrained photometric redshifts made possible through deep medium-bandwidth imaging at 1–2 μm. We combine this with Hubble Space Telescope imaging from the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey, allowing for the efficient selection of both blue and red galaxies down to stellar masses of ∼109.5 M☉ at z ∼ 2.5. The total surveyed area is 316 arcmin2 distributed over three independent fields. We supplement these data with the wider and shallower NEWFIRM Medium-Band Survey to provide stronger constraints at high masses. Several studies at z ⩽ 1.5 have revealed a steepening of the slope at the low-mass end of the SMF, leading to an upturn at masses <1010 M☉ that is not well described by a standard single-Schechter function. We find evidence that this feature extends to at least z ∼ 2 and that it can be found in both the star-forming and quiescent populations individually. The characteristic mass (M*) and slope at the lowest masses (α) of a double-Schechter function fit to the SMF stay roughly constant at Log(M/M☉) ∼ 10.65 and ∼ − 1.5, respectively. The SMF of star-forming galaxies has evolved primarily in normalization, while the change in shape is relatively minor. Our data allow us, for the first time, to observe a rapid buildup at the low-mass end of the quiescent SMF. Since z = 2.5, the total stellar mass density of quiescent galaxies (down to 109 M☉) has increased by a factor of ∼12, whereas the mass density of star-forming galaxies only increases by a factor of ∼2.2.