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arXiv 0907.2819astro-ph.CO
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从z = 0到z=1紫外选择星系的红外辐射

The infrared emission of ultraviolet selected galaxies from z = 0 to z=1

V. Buat, T. T. Takeuchi, D. Burgarella, E. Giovannoli, K. L. Murata

摘要:

我们选取了z=0、z~0.7和z~1的UV静止坐标系中的星系以及z~1的LBG样本,这些样本的建立是为了在任何红移下都能获得相同的光度范围。红外和紫外光光度与z的演变进行了分析,为个别星系,以及在光度函数。LIR/LUV比值用于测量粉尘衰减。在我们的大部分样本星系中,这个比值并不随z的变化而变化,但在强尘埃衰减的星系和紫外光源的星系中,发现了一些变化趋势:L_IR/L_UV>10的星系在z>0时比z=0时更常见,且最大的L_IR/L_UV值出现在紫外暗天体;相反,我们的样本中最明亮的星系(L_UV> 2 × 10^{10} L_sun$),在z=1时检测到,比较暗的星系表现出较低的尘埃衰减。L_IR/L_UV在所有红移下都随星系K静止坐标系光度的增加而增加,并与L_UV存在剩余反相关。最大质量和紫外线亮度的星系表现出相当大的比恒星形成率。LBG表现出系统较低的尘埃衰减比紫外选择星系相同的光度,但类似的特定的恒星形成率。UV+IR光度函数的分析得出的结论是,在z = 1之前,UV选择星系的大部分恒星形成活动都是在IR中发射的。虽然我们能够从z=0.7的UV选择中恢复所有的恒星形成,但在z = 1时,我们错过了大部分比~ 10^{11} L_sun更明亮的星系。发现Lyman Break Galerkin的影响更大。

英文摘要:

We select galaxies in UV rest-frame at z=0, z~0.7 and z~1 together with a sample of LBGs at z~1, the samples are built in order to sample the same range of luminosity at any redshift. The evolution of the IR and UV luminosities with z is analysed for individual galaxies as well as in terms of luminosity functions. The L_IR/L_UV ratio is used to measure dust attenuation. This ratio does not exhibit a strong evolution with z for the bulk of our sample galaxies but some trends are found for galaxies with a strong dust attenuation and for UV luminous sources: galaxies with L_IR/L_UV>10 are more frequent at z>0 than at z=0 and the largest values of L_IR/L_UV are found for UV faint objects; conversely the most luminous galaxies of our samples (L_UV> 2 10^{10} L_sun$), detected at z=1, exhibit a lower dust attenuation than the fainter ones. L_IR/L_UV increases with the K rest-frame luminosity of the galaxies at all the redshifts considered and shows a residual anti-correlation with L_UV. The most massive and UV luminous galaxies exhibit quite large specific star formation rates. LBGs exhibit systematically lower dust attenuation than UV selected galaxies of same luminosity but similar specific star formation rates. The analysis of the UV+IR luminosity functions leads to the conclusion that up to z = 1 most of the star formation activity of UV selected galaxies is emitted in IR. Whereas we are able to retrieve all the star formation from our UV selection at z=0.7, at z = 1 we miss a large fraction of galaxies more luminous than ~ 10^{11} L_sun. The effect is found larger for Lyman Break Galaxies.

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