The faint regions of galaxies, groups and clusters hold important clues about how these objects formed, and surface photometry at optical and near-infrared wavelengths represents a powerful tool for studying such structures. Here, we identify a hitherto unrecognized problem with this technique, related to how the night sky flux is typically measured and subtracted from astronomical images. While most of the sky flux comes from regions between the observer and the target object, a small fraction - the extragalactic background light (EBL) - comes from behind. We argue that since this part of the sky flux can be subject to extinction by dust present in the galaxy/group/cluster studied, standard reduction procedures may lead to a systematic oversubtraction of the EBL. Even very small amounts of extinction can lead to spurious features in radial surface surface brightness profiles and colour maps of extended objects. We assess the likely impact of this effect on a number of topics in extragalactic astronomy where very deep surface photometry is currently attempted, including studies of stellar halos, starburst host galaxies, disc truncations and diffuse intragroup/intracluster light. We argue that EBL extinction may provide at least a partial explanation for the anomalously red colours reported for the halos of disc galaxies and the hosts of local starburst galaxies. EBL extinction effects also mimic truncations in discs with unusually high dust opacities, but are unlikely to be the cause of such features in general. Failure to account for EBL extinction can also give rise to a non-negligible underestimate of intragroup and intracluster light at the faintest surface brightness levels currently probed. (Abridged)
S-CANDELS: The Spitzer-Cosmic Assembly Near-Infrared Deep Extragalactic Survey. Survey Design, Photometry, and Deep IRAC Source Counts
斯皮策宇宙大会深近红外河外遗产调查（S-CANDELS; PI G。Fazio）是一个第8周期的探索计划，旨在探测非常高红移（z > 5）的星系。为了减轻宇宙变化的影响，并利用哈勃空间望远镜多周期财政计划CANDELS在多个波段的深度同延覆盖，S-CANDELS在五个相距甚远的河外区域进行：UKIDSS超深巡天、扩展钱德拉深场南、COSMOS、HST深场北和扩展格罗斯带。S-CANDELS建立在斯皮策扩展深度调查（SEDS）现有的这些领域的覆盖范围之上，将积分时间从12小时增加到总共50小时，但在较小的区域内，0.16平方度。额外的深度显著增加了微弱星等下的勘测完整性。本文介绍了S-CANDELS调查的设计、处理和公开提供的数据产品。我们目前的IRAC双波段3.6+4.5微米目录达到26.5 AB MAG的深度。深IRAC计数的大约135,000个星系检测的S-CANDELS是一致的模型的基础上已知的星系种群。比早期斯皮策/IRAC调查更深的深度增加并没有揭示离散源对弥漫的宇宙红外背景（CIB）的显着额外贡献。因此，它仍然是正确的，只有大约一半的估计CIB通量从COBE/DIRBE解决。
The VLT-FLAMES Tarantula Survey XVI. The optical+NIR extinction laws in 30 Doradus and the photometric determination of the effective temperatures of OB stars
Cosmic Distances Calibrated to 1% Precision with Gaia EDR3 Parallaxes and Hubble Space Telescope Photometry of 75 Milky Way Cepheids Confirm Tension with LambdaCDM
JWST Advanced Deep Extragalactic Survey (JADES) Data Release 5: Photometric Catalog
Department of Astronomy and Astrophysics, University of California, Santa Cruz（加州大学圣克鲁兹分校天体物理学与天文学系）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Steward Observatory, University of Arizona（亚利桑那大学斯图德天文台）；AURA for the European Space Agency (ESA), Space Telescope Science Institute（欧洲航天局（ESA）所属美国大学研究协会（AURA）太空望远镜科学研究所）；Centro de Astrobiología (CAB), CSIC–INTA（西班牙国家航空航天技术研究所（INTA）/西班牙国家科学研究委员会（CSIC）天体生物学中心）
