DISCOVERY OF LYMAN BREAK GALAXIES AT z ∼ 7 FROM THE zFourGE SURVEY
DISCOVERY OF LYMAN BREAK GALAXIES AT z ∼ 7 FROM THE zFourGE SURVEY
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zFourGE 调查发现 z ≤ 7 处的莱曼断裂星系
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Willner
中科院分区：
文献类型：
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作者：
V. Tilvi;C. Papovich;K. Tran;I. Labbé;L. Spitler;Caroline M. S. Straatman;S. E. Persson;A. Monson;K. Glazebrook;R. Quadri;P. V. Dokkum;M. Ashby;S. Faber;G. Fazio;S. Finkelstein;H. Ferguson;N. Grogin;G. Kacprzak;D. Kelson;A. Koekemoer;D. Murphy;P. McCarthy;J. Newman;B. Salmon;S. Willner
红移z>；6的恒星形成星系很可能是宇宙再电离的原因，研究这些星系的性质是很重要的。我们给出了三个候选的z∼7 Lyman Break星系(LBG)，它们来自深四星星系演化(ZFOURGE)观测到的CANDELS/COSMOS区域中的155arcmin2区域。FourStar中带滤光片提供了相当于R∼10光谱的功能，可以清晰地区分z∼7LBGS和棕矮星。即使在使用哈勃太空望远镜成像时，基于物体角大小的恒星和星系之间的区分也可能变得不可靠；至少有一个非常紧凑的z∼7候选者(半高宽∼0.5-1kpc)与点源无法区分。与宽带导出的红移相比，中带滤光片提供了更窄的红移分布。利用三个候选z∼7得到的UV光度函数与以前的研究一致，表明亮端(MUV∼−21.6mag)从z∼7演化到z∼5。通过拟合星系的光谱能量分布，我们预测了最亮的两个LBG的Lyα等效宽度，并发现Lyα线的存在影响了中等波段的通量，从而改变了对恒星质量和UV光谱斜率的约束。这说明了仅使用宽带光度法推导LBG属性的局限性。得出明亮的LBGS的比恒星形成率为∼13Gyr−1，略高于低光度LBGS，这意味着这些星系的恒星形成率随着恒星质量的增加而增加。
Star-forming galaxies at redshifts z > 6 are likely responsible for the reionization of the universe, and it is important to study the nature of these galaxies. We present three candidates for z ∼ 7 Lyman break galaxies (LBGs) from a 155 arcmin2 area in the CANDELS/COSMOS field imaged by the deep FourStar Galaxy Evolution (zFourGE) survey. The FourStar medium-band filters provide the equivalent of R ∼ 10 spectroscopy, which cleanly distinguishes between z ∼ 7 LBGs and brown dwarf stars. The distinction between stars and galaxies based on an object's angular size can become unreliable even when using Hubble Space Telescope imaging; there exists at least one very compact z ∼ 7 candidate (FWHM ∼ 0.5–1 kpc) that is indistinguishable from a point source. The medium-band filters provide narrower redshift distributions compared with broadband-derived redshifts. The UV luminosity function derived using the three z ∼ 7 candidates is consistent with previous studies, suggesting an evolution at the bright end (MUV ∼ −21.6 mag) from z ∼ 7 to z ∼ 5. Fitting the galaxies' spectral energy distributions, we predict Lyα equivalent widths for the two brightest LBGs, and find that the presence of a Lyα line affects the medium-band flux thereby changing the constraints on stellar masses and UV spectral slopes. This illustrates the limitations of deriving LBG properties using only broadband photometry. The derived specific star-formation rates for the bright LBGs are ∼13 Gyr−1, slightly higher than the lower-luminosity LBGs, implying that the star-formation rate increases with stellar mass for these galaxies.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.