Chen H W, Lanzetta K M, Pascarelle S, Yahata N
Observatories of the Carnegie Institution of Washington, Pasadena, California 91101, USA.
Nature. 2000 Nov 30;408(6812):562-4. doi: 10.1038/35046031.
Observations of distant galaxies are important both for understanding how galaxies form and for probing the physical conditions of the Universe at early times. It is, however, very difficult to identify galaxies at redshifts z > 5, because they are so faint and have few spectral characteristics. We previously reported the probable identification of a galaxy at z = 6.68, based on one line and an apparent break in the spectrum just shortwards of that, which we interpreted as Lyman alpha emission and the Lyman alpha break, where photons with shorter wavelengths are absorbed by the intervening neutral hydrogen gas. Here we present optical photometry that shows moderate detections of light in the B- and V-band images, which are inconsistent with the expected absence of flux shortwards of the Lyman alpha break for alpha galaxy at z > 5, and inconsistent with the previous flux measurement. Moreover, the spectral energy distribution for this object cannot readily be fitted by any known galaxy spectral template at any redshift, so the redshift is undetermined.
对遥远星系的观测对于理解星系如何形成以及探究早期宇宙的物理条件都非常重要。然而，要识别红移z>5的星系非常困难，因为它们非常暗淡且光谱特征很少。我们之前曾报道过一个可能红移为z = 6.68的星系的识别，这是基于一条谱线以及该谱线稍短波长处的一个明显间断，我们将其解释为莱曼α发射和莱曼α间断，在那里波长较短的光子被中间的中性氢气体吸收。在这里，我们展示了光学测光结果，该结果显示在B波段和V波段图像中有适度的光探测，这与z>5的α星系在莱曼α间断短波方向预期不存在通量不一致，也与之前的通量测量结果不一致。此外，这个天体的光谱能量分布在任何红移下都不能轻易地用任何已知的星系光谱模板来拟合，因此红移是不确定的。
