The Time-Dependent Distribution of Optical Polarization Angle Changes in Blazars
S. Kiehlmann, D. Blinov, I. Liodakis, V. Pavlidou, A. C. S. Readhead, E. Angelakis, C. Casadio, T. Hovatta, N. Kylafis, A. Mahabal, N. Mandarakas, I. Myserlis, … 展开作者
S. Kiehlmann, D. Blinov, I. Liodakis, V. Pavlidou, A. C. S. Readhead, E. Angelakis, C. Casadio, T. Hovatta, N. Kylafis, A. Mahabal, N. Mandarakas, I. Myserlis, G. V. Panopoulou, T. J. Pearson, A. Ramaprakash, P. Reig, R. Skalidis, A. Slowikowska, K. Tassis, J. A. Zensus
At optical wavelengths, blazar Electric Vector Position Angle (EVPA) rotations linked with gamma-ray activity have been the subject of intense interest and systematic investigation for over a decade. One difficulty in the interpretation of EVPA rotations is the inherent 180° ambiguity in the measurements. It is therefore essential, when studying EVPA rotations, to ensure that the typical time-interval between successive observations -- i.e. the cadence -- is short enough to ensure that the correct modulo 180° value is selected. This optimal cadence depends on the maximum intrinsic EVPA rotation speed in blazars, which is currently not known. In this paper we address the following questions for the RoboPol sample: What range of rotation speeds for rotations greater than 90° can we expect? What observation cadence is required to detect such rotations? Have rapid rotations been missed in EVPA rotation studies thus far? What fraction of data is affected by the ambiguity? And how likely are detected rotations affected by the ambiguity? We answer these questions with three seasons of optical polarimetric observations of a statistical sample of blazars sampled weekly with the RoboPol instrument and an additional season with daily observations. We model the distribution of EVPA changes on time scales from 1-30 days and estimate the fraction of changes exceeding 90°. We show that at least daily observations are necessary to measure >96% of optical EVPA variability in the RoboPol sample of blazars correctly and that intra-day observations are needed to measure the fastest rotations that have been seen thus far.
Time-variable polarization is an extremely valuable observational tool to probe the dynamical physical conditions of blazar jets. Since 2008, we have been monitoring the flux and linear polarization of a sample of gamma-ray bright blazars at optical frequencies. Some of the observations were performed on nightly or intra-night time-scales in four optical bands, providing information on the frequency and time dependence of the polarization. The observed behavior is similar to that found in simulations of turbulent plasma in a relativistic jet that contains a standing shock and/or a helical back…
Polarization offers a unique view in the physical processes of astrophysical jets. We report on optical circular polarization observations of two famous blazars, namely 3C 279 and PKS 1510-089, at high linearly polarized states. This is the first time PKS 1510-089 is observed in optical circular polarization. While only upper limits can be extracted from our observing campaign, the non-detection of optical circular polarization allows us to provide meaningful constraints on their magnetic field strength and jet composition. We find that high-energy emission models requiring high magnetic field…
Systematic Study of Gamma-ray bright Blazars with Optical Polarization and Gamma-ray Variability
耀变体是高度可变的活动星系核,其发射从无线电到伽马射线的所有波长的辐射。来自耀变体的偏振辐射是低能同步辐射的一个关键证据,并且它也变化很大。耀变体的偏振对于理解喷流的起源、约束和传播是很有意义的。然而,尽管已经进行了大量的测量,但射流产生、成分和可变性背后的机制仍然存在争议。我们在2008年7月至2014年12月期间对45颗耀变体进行了同步的伽马射线和光学双偏振测量观测,以研究变化的机制并寻找耀变体的几个子类之间的基本关系。我们确定的最大程度的光学线性偏振和伽马射线光度或伽马射线的光通量的比率之间的相关性。由于最大偏振度取决于磁场的条件(混沌或有序),这一结果意味着不同类型耀变体(FSRQs vs. BL Lac)之间pc尺度相对论喷流中磁场的内在排列存在系统性差异,因此也意味着不同类型射电星系(FR Is vs. FR IIs)之间的差异。
Optical polarization variability and its relation to gamma-ray activity in blazars
University of Crete(克里特大学);Foundation for Research and Technology-Hellas(希腊研究与技术基金会);Institute of Astrophysics, Foundation for Research and Technology-Hellas(希腊研究与技术基金会天体物理研究所);Institute of Astrobiology, University of Crete(克里特大学天体生物学研究所)
Testing the Correlations between X-ray Spectral Properties and Polarization for High Synchrotron Peaked Blazars
Science & Technology Institute, Universities Space Research Association(科学与技术学院,美国太空研究协会);NASA Marshall Space Flight Center(美国国家航空航天局马歇尔太空飞行中心);Institute of Astrophysics, Foundation for Research and Technology-Hellas(天体物理研究所,希腊研究与技术基金会);INAF Osservatorio Astronomico di Brera(意大利国家天体物理研究所布雷拉天文台);Department of Physics, University of Crete(克里特大学物理系);INAF Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台)
The spectral energy distributions (SEDs) of some blazars exhibit an ultraviolet (UV) and/or soft X-ray excess, which can be modelled with different radiation mechanisms. Polarization measurements of the UV/X-ray emission from blazars may provide new and unique information about the astrophysical environment of blazar jets, and could thus help to distinguish between different emission scenarios. In this paper, a new Monte-Carlo code -- MAPPIES (Monte-Carlo Applications for Partially Polarized Inverse External-Compton Scattering) -- for polarization-dependent Compton scattering is used to simula…
Energy-Dependent Polarization Angle Variability as a Robust Diagnostic for Blazar Flaring Mechanisms
University of Maryland Baltimore County(马里兰大学巴尔的摩县分校);NASA Goddard Space Flight Center(美国国家航空航天局戈达德太空飞行中心);Washington University in St Louis(华盛顿大学圣路易斯分校);Los Alamos National Lab(洛斯阿拉莫斯国家实验室);New Mexico Consortium(新墨西哥联盟)
Photopolarimetric Monitoring of Blazars in the Optical and Near-Infrared Bands with the Kanata Telescope. I. Correlations between Flux, Color, and Polarization
Peculiar Behavior of Optical Polarization in Blazar 1ES 1959+650: Role of Jet Magnetic Field and Geometry
Homi Bhabha National Institute(霍米·巴巴国立研究所);Astrophysical Sciences Division, Bhabha Atomic Research Centre(巴哈原子研究中心天体物理科学部);Aryabhatta Research Institute of Observational Sciences(阿耶波多观测科学研究所以)
Both leptonic and hadronic emission processes may contribute to blazar jet emission; which dominates in blazars's high energy emission component remains an open question. Some intermediate synchrotron peaked blazars transition from their low to high energy emission components in the X-ray band making them excellent laboratories to probe both components simultaneously, and good targets for the newly launched Imaging X-ray Polarimetry Explorer. We characterize the spectral energy distributions for three such blazars: CGRaBS~J0211+1051, TXS~0506+056, and S5~0716+714, predicting their X-ray polari…
Polarization Dynamics of X-Ray Synchrotron Emission from a Multi-Zone Blazar Jet
Washington University in St Louis(圣路易斯华盛顿大学);University of Maryland Baltimore County(马里兰大学巴尔的摩县分校);NASA Goddard Space Flight Center(美国国家航空航天局戈达德太空飞行中心)
Self-consistent modeling of energy-dependent synchrotron polarization in blazars with application to Mrk 421
Centre for Space Research, North-West University(北威特大学空间研究中心);Instituto de Física, Universidade Federal de Goiás(戈亚斯联邦大学物理研究所);Université Paris Cité, CNRS, Astroparticule et Cosmologie(巴黎西岱大学,法国国家科学研究中心,亚原子粒子与宇宙学);Ruhr Astroparticle and Plasma Physics Center (RAPP Center)(鲁尔天体粒子与等离子体物理中心(RAPP中心));Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute (AIRUB)(波鸿鲁尔大学,物理与天文学院,天文研究所(AIRUB))
Radiative Transfer Modeling of Radio-band Linear Polarization Observations as a Probe of the Physical Conditions in the Jets of Gamma-ray Flaring Blazars
Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability
Blazars are relativistic magnetized plasma outflows from supermassive black holes that point very close to our line of sight. Their emission is nonthermal dominated and highly variable across the entire electromagnetic spectrum. Relativistic magnetic reconnection has been proposed as the driver of particle acceleration during blazar flares. While recent particle-in-cell simulations have self-consistently studied the evolution of magnetic reconnection and particle acceleration therein, the resulting radiation signatures have not been systematically explored. In particular, the polarization sign…
We propose that the interaction between the axionlike particles (ALPs) and photons can be a possible origin of optical circular polarization (CP) in blazars. Given that there is no definite detection of optical CP at $\sim0.1\%$ level, a rough limit on ALP-photon coupling can be obtained, specifically $g_{aγ}\cdot B_\mathrm{T0}\lesssim7.9\times10^{-12}~\mathrm{G\cdot GeV}^{-1}$ for $m_{a}\lesssim 10^{-13}~\mathrm{eV}$, depending on the magnetic field configuration of the blazar jet. Obviously, for the blazar models with a larger magnetic field strength, such as hadronic radiation models, this …