Extragalactic very-high-energy (VHE; E>100 GeV) sources are unique objects to study the most powerful particle accelerators in nature, as active galactic nuclei are likely sources of ultra-high-energy cosmic rays. BL Lacertae blazars are the most frequent extragalactic objects found in the VHE gamma-ray catalogs. It is very difficult to estimate their redshifts, considering they have no strong enough optical spectral features, hence ∼20% of them have unknown or poorly constrained redshifts. KUV 00311–1938 is a VHE BL Lacertae blazar, with an uncertain redshift in the range of 0.5<z<0.98. We have obtained deep spectroscopy using Gemini and the GTC telescopes of KUV 00311–1938 and its surroundings with high signal-to-noise ratio in 2016–2017. The lack of features did not allow us to determine the spectroscopic redshift of KUV 00311–1938; nevertheless, we obtain a lower limit of z≳0.475. We determined the redshifts of 41 galaxies observed in the field-of-view of the blazar and through a population study, identified three pairs and four groups consisting of 3 or 4 members with redshifts in the range z=0.1468–0.4756. Due to the absence of a large group of galaxies, we could not associate KUV 00311–1938 with any of the groups detected.

银河系超高能（VHE；E > 100 GeV）源是研究自然界中最强大的粒子加速器的独特对象，因为活跃的银河核可能是超高能宇宙射线的源。BL Lacertae blazars是VHE伽玛射线目录中最常见的河外物体。考虑到它们没有足够强的光谱特征，估计它们的红移非常困难，因此约有20％的红移未知或受约束程度很低。KUV 00311–1938是VHE BL Lacertae blazar，不确定红移范围为0.5 < z<0.98。我们在2016-2017年使用双子星和KUV 00311-1938及其附近的GTC望远镜获得了高光谱信噪比的深层光谱。缺少功能部件使我们无法确定KUV 00311–1938的光谱红移。尽管如此，我们得到的下限ž ≳0.475。我们确定了在Blazar视野中观察到的41个星系的红移，并通过人口研究确定了三对和四组，由3或4个成员组成，其红移在z = 0.1468-0.4756范围内。由于不存在大量星系，因此我们无法将KUV 00311–1938与发现的任何星系相关联。