arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0901.3845astro-ph.CO
收藏

z=3 Ly-alpha发射星系的建桥巡天II:巡天的完成

The Building the Bridge survey for z=3 Ly-alpha emitting galaxies II: Completion of the survey

L. F. Grove, J. P. U. Fynbo, C. Ledoux, M. Limousin, P. Moller, K. Nilsson, B. Thomsen

摘要:

(节录)。我们的目标是通过探测恒星形成星系在z ~ 3处光度函数的暗端,来弥合z ~ 3处吸收选择星系和发射选择星系之间的差距。我们已经进行了窄带成像在三个领域的干预类星体吸收(阻尼Ly $α$吸收和两个莱曼限制系统)使用VLT。我们的目标是在红移2.85,3.15和3.20的Ly-alpha。我们发现,在所有三个视场中,直到我们的探测极限约为3 × 10^41尔格·s^-1时,每单位红移每平方弧分都有10个Ly-alpha发射体的表面密度。光度函数与其他类似红移的巡天观测结果一致。对于大多数莱曼破裂星系巡天,大约85%的源比R=25.5的规范极限更暗。在这三个场中,我们都没有探测到类星体吸收体的辐射对应物。特别地,我们没有检测到Z=2.85阻尼Ly-alpha吸收体朝向Q2138-4427的对应物。Ly-alpha发射体的窄带巡天对于探测z~3处光度函数的暗端是极好的。这类物体的表面密度非常高。这与其他研究所推断的光度函数的暗端的非常陡峭的斜率是一致的。这个微弱的星系群在早期宇宙中发挥着核心作用。有证据表明,这一群体是主导综合恒星形成活动,负责大部分的电离光子在z~3,也可能负责大部分的星系际介质的富集。

英文摘要:

(Abridged). We aim at bridging the gap between absorption selected and emission selected galaxies at z~3 by probing the faint end of the luminosity function of star-forming galaxies at z~3. We have performed narrow-band imaging in three fields with intervening QSO absorbers (a damped Ly$α$ absorber and two Lyman-limit systems) using the VLT. We target Ly-alpha at redshifts 2.85, 3.15 and 3.20. We find a consistent surface density of about 10 Ly-alpha-emitters per square arcmin per unit redshift in all three fields down to our detection limit of about 3x10^41 ergs s^-1. The luminosity function is consistent with what has been found by other surveys at similar redshifts. About 85% of the sources are fainter than the canonical limit of R=25.5 for most Lyman-break galaxy surveys. In none of the three fields do we detect the emission counterparts of the QSO absorbers. In particular we do not detect the counterpart of the z=2.85 damped Ly-alpha absorber towards Q2138-4427. Narrow-band surveys for Ly-alpha emitters are excellent to probe the faint end of the luminosity function at z~3. There is a very high surface density of this class of objects. This is consistent with a very steep slope of the faint end of the luminosity function as has been inferred by other studies. This faint population of galaxies is playing a central role in the early Universe. There is evidence that this population is dominating the integrated star-formation activity, responsible for the bulk of the ionizing photons at z~3 and likely also responsible for the bulk of the enrichment of the intergalactic medium.

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。

↑