arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0904.0349astro-ph.CO
收藏

u带光度函数从红移1.2到0的演化

Evolution of the u-band luminosity function from redshift 1.2 to 0

Matthew Prescott, Ivan K. Baldry, Phil A. James

摘要:

我们使用斯隆数字巡天(SDSS)u波段星系巡天(uGS)和深进化探索探测器2(DEEP 2)的数据,产生和分析了红色和蓝色星系群的u波段光度函数。从41575 SDSS uGS星系和24561深星系的光谱样本,我们产生的颜色星等图,并利用星系的颜色双峰分离红色和蓝色的人口。用1/Vmax方法测定了0.01 < z < 1.2范围内8个红移片的光度函数,并用Schechter函数进行拟合,表明M星存在着显著的演化,总星族的亮度增加了1.4 mag。Schechter函数的积分产生了u带亮度密度到z ~ 1的演化。通过将演化参数化为与(1+z)^beta成比例的密度,我们发现组合种群的beta = 1.36 +- 0.2,蓝色种群的beta = 2.09 +- 0.2。通过去除旧的恒星星族对u波段光度密度的贡献,并校正尘埃衰减,我们估计宇宙恒星形成率的演化为beta(SFR)= 2.5 +- 0.3。我们的结果和更高的演化率之间的差异,使用红外线和远紫外线测量可以调和考虑的可能性,如低估的尘埃校正在高红移或恒星初始质量函数的演变。

英文摘要:

We produce and analyse u-band luminosity functions for the red and blue populations of galaxies using data from the Sloan Digital Sky Survey (SDSS) u-band Galaxy Survey (uGS) and Deep Evolutionary Exploratory Probe 2 (DEEP2) survey. From a spectroscopic sample of 41575 SDSS uGS galaxies and 24561 DEEP2 galaxies, we produce colour magnitude diagrams and make use of the colour bimodality of galaxies to separate red and blue populations. Luminosity functions for eight redshift slices in the range 0.01 < z < 1.2 are determined using the 1/Vmax method and fitted with Schechter functions showing that there is significant evolution in M-star, with a brightening of 1.4 mags for the combined population. The integration of the Schechter functions yields the evolution in the u-band luminosity density out to z ~ 1. By parametrizing the evolution as density proportional to (1+z)^beta, we find that beta = 1.36 +- 0.2 for the combined populations and beta = 2.09 +- 0.2 for the blue population. By removing the contribution of the old stellar population to the u-band luminosity density and correcting for dust attenuation, we estimate the evolution in the star formation rate of the Universe to be beta(SFR) = 2.5 +- 0.3. Discrepancies between our result and higher evolution rates measured using the infrared and far-UV can be reconciled by considering possibilities such as an underestimated dust correction at high redshifts or evolution in the stellar initial mass function.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑