We report the first study to characterise intranight variability of the blazar class from the perspective of (rest-frame) UV emission. For this, we carried out intranight optical monitoring of 14 flat-spectrum radio quasars (FSRQs) located at high redshifts (1.5 < $z$ < 3.7), in 42 sessions of median duration $\sim$ 5.4 hr. These sources were grouped into two samples distinguished by published fractional optical polarisation: (i) nine low-polarisation sources with $p_{opt} < 3\%$ and (ii) five high-polarisation sources. Unexpectedly, a high duty cycle (DC $\sim$ 30$\%$) is found for intranight variability (with amplitude $ψ> 3\%$) of the low-polarisation sources. This DC is a few times higher than that reported for low-polarisation FSRQs located at moderate redshifts ($z$ $\sim$ 0.7) and hence typically monitored in the rest-frame blue-optical. Further, we found no evidence for an increased intranight variability of UV emission with polarisation, in contrast to the strong correlation found for intranight variability of optical emission. We briefly discuss this in the context of an existing scenario which posits that the nonthermal UV emission of blazars arises from a relativistic particle population different from that radiating up to near-infrared/optical frequencies.
Constraints on the Intranight Optical Variability of Intermediate-Mass Black Hole Candidates
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；University of Chinese Academy of Sciences（中国科学院大学）；Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso（瓦尔帕莱索大学理学院物理与天文学研究所）；Millennium Nucleus on Transversal Research and Technology to Explore Supermassive Black Holes (TITANS)（探索超大质量黑洞跨学科研究和技术千年核（TITANS））；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）
VHE gamma-ray intranight variability from BL Lacertae during the extreme flaring state of 2022
Tokai University（东海大学）；Institute for Cosmic Ray Research, University of Tokyo（东京大学宇宙射线研究所）；INFN and Università degli Studi di Siena（意大利国家核物理研究所和锡耶纳大学）；Université Paris-Saclay（巴黎萨克雷大学）；Université Paris Cité（巴黎西岱大学）；CEA（法国原子能和替代能源委员会）；CNRS（法国国家科学研究中心）；FSLAC IRL 2009, CNRS/IAC（中法天文卫星项目，法国国家科学研究中心/加那利天体物理研究所）；Institut de Ciències del Cosmos, Universitat de Barcelona（巴塞罗那大学宇宙科学研究所）；Instituto de Astrofísica de Andalucía-CSIC（安达卢西亚天体物理研究所-西班牙高等科学研究理事会）；Department of Astronomy, University of Geneva（日内瓦大学天文学系）；INFN Sezione di Napoli（意大利国家核物理研究所那不勒斯分部）；INAF - Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Max-Planck-Institut für Physik（马克斯·普朗克物理研究所）
