In the last 20 years, modern wide-field surveys discovered a new class of peculiar transients, which lie in the luminosity gap between standard supernovae and classical novae. These transients are often called “intermediate luminosity optical transients” or “gap transients”. They are usually distinguished in subgroups based on their phenomenology, such as supernova impostors, intermediate luminosity red transients, and luminous red novae. In this review, we present a brief overview of their observational features and possible physical scenarios to date, in the attempt to understand their nature.

中文翻译：

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间隙瞬态与环恒星介质相互作用

在过去的 20 年里，现代广域调查发现了一类新的奇特瞬变，它位于标准超新星和经典新星之间的光度差距中。这些瞬变通常被称为“中间光度光学瞬变”或“间隙瞬变”。它们通常根据其现象学分为亚组，例如超新星冒名顶替者、中等光度红色瞬变和发光红色新星。在这篇综述中，我们简要概述了它们迄今为止的观测特征和可能的物理场景，以试图了解它们的性质。