Investigation on the X-ray emission of NGC 4051 during its 2009 optical/UV-X-ray dissociation phase
Jiangxi Province Key Laboratory of Applied Optical Technology, School of Physical Science and Intelligent Education, Shangrao Normal College（上饶师范学院物理科学与智能教育学院）；School of Digital Technology Application Industry, Shangrao Normal College（上饶师范学院数字技术应用产业学院）
Minhua Zhou, Xinling Wu, Lei Xu, Nannan Chen
备注：
11 pages, 6 figures, accepted for publication in MNRAS
This study investigates the X-ray characteristics of jet-associated radio-quiet AGNs across distinct optical/UV to X-ray correlation phases. Quasi-simultaneous optical/UV/X-ray observations of NGC 4051 from May-June 2009, obtained through Swift and XMM-Newton, reveal a temporal dichotomy: a strong optical/UV to X-ray correlation dominates the initial observation phase (before May 27), followed by an optical/UV flare event concurrent with X-ray flux suppression in the latter period. Our multi-method analysis of XMM-Newton data, incorporating short-term X-ray variability assessment, spectral decomposition, and RGS spectral analysis, identifies significant inter-phase X-ray emission disparities. During optical/UV flaring episodes, compared to the correlated phase, we observe: attenuated short-term X-ray variability amplitudes, enhanced soft X-ray absorption, suppressed intrinsic hard X-ray flux, and more prominent RGS emission-line features. Notably, these X-ray characteristics during optical/UV flaring intervals show no statistically significant deviations from pre-flare low-state X-ray emission patterns. These non-synchronous optical/UV-X-ray variations contradict predictions from both reprocessing models, starburst-driven emission scenarios, and the simplistic absorption models. While potential jet-related mechanisms remain ambiguous, our findings demonstrate strong consistency with predictions from the inhomogeneous accretion disk perturbation framework.
Probing the $γ$-ray Emission Origin of Two Star-forming Galaxies NGC 2403 and NGC 3424 with the Fermi-LAT
Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；University of the Chinese Academy of Sciences（中国科学院大学）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；TIANFU Cosmic Ray Research Center（天府宇宙线研究中心）；IRAP, Université de Toulouse, CNRS, UPS, CNES（图卢兹大学IRAP研究所）
