We present the results of a study of different statistical methods currently used in the literature to analyse the (micro)variability of active galactic nuclei (AGNs) from ground-based optical observations. In particular, we focus on the comparison between the results obtained by applying the so-called C and F statistics, which are based on the ratio of standard deviations and variances, respectively. The motivation for this is that the implementation of these methods leads to different and contradictory results, making the variability classification of the light curves of a certain source dependent on the statistics implemented.
For this purpose, we re-analyse the results on an AGN sample observed along several sessions with the 2.15m "Jorge Sahade" telescope (CASLEO), San Juan, Argentina. For each AGN we constructed the nightly differential light curves. We thus obtained a total of 78 light curves for 39 AGNs, and we then applied the statistical tests mentioned above, in order to re-classify the variability state of these light curves and in an attempt to find the suitable statistical methodology to study photometric (micro)variations. We conclude that, although the $C$ criterion is not proper a statistical test, it could still be a suitable parameter to detect variability and that its application allows us to get more reliable variability results, in contrast with the F test.
Only obscured yet luminous active galactic nuclei are closely associated with galaxy mergers: Direct observational evidence from type 2 active galactic nuclei
Kyungpook National University（庆北国立大学）；Sejong University（世宗大学）；Pusan National University（釜山国立大学）；Korea Astronomy and Space Science Institute (KASI)（韩国天体宇宙科学研究所）
Origins of the UV continuum and Balmer emission lines in Little Red Dots: observational validation of dense gas envelope models enshrouding the AGN
Dunlap Institute for Astronomy and Astrophysics（邓普天文学与天体物理研究所）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学柯夫利天文学与天体物理研究所）；David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto（多伦多大学大卫·A·邓普普天文学与天体物理学系）；NRC Herzberg（国家研究委员会赫茨伯格研究所）
Seeing through the dust: Unraveling near-infrared variability in type 2 active galactic nuclei
Instituto de Física y Astronomía, Universidad de Valparaíso（瓦帕拉索大学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与技术千年核）；Millennium Institute of Astrophysics (MAS)（天体物理学千年研究所）；European Southern Observatory（欧洲南方天文台）；Departamento de Astronomía, Universidad de Chile（智利大学天文学系）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Department of Physics & Astronomy, Bishop’s University（主教大学物理与天文学系）
NEXUS: Spectral Variability of Little Red Dots and Blue Active Galactic Nuclei at $2 \lesssim z \lesssim 6$
University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign（美国国家超级计算应用中心）；Princeton University（普林斯顿大学）；University of Michigan（密歇根大学）
