A radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare states

Abstract

The nearby type-II AGN 1ES1927+654 went through a violent changing-look (CL) event beginning December 2017 during which the optical and UV fluxes increased by four magnitudes over a few months, and broad emission lines newly appeared in the optical/UV. By July 2018 the X-ray coronal emission had completely vanished, only to reappear a few months later. In this work we report the evolution of the radio, optical, UV and X-rays from the pre-flare state through mid-2021 with new and archival data from the Very Long Baseline Array (VLBA), the European VLBI Network, the Very Large Array (VLA), the Telescopio Nazionale Galileo (TNG), Gran Telescopio Canarias (GTC), The Neil Gehrels Swift observatory and XMM-Newton. The main results from our work are: (1) The source has returned to its pre-CL state in optical, UV, and X-ray; the disk-corona relation has been re-established as has been in the pre-CL state, with an ${\alpha }_{\mathrm{OX}}\sim 1.02$. The optical spectra are dominated by narrow emission lines. (2) The UV light curve follows a shallower slope of $\propto t^{-0.91\pm 0.04}$ compared to that predicted by a tidal disruption event. We conjecture that a magnetic flux inversion event is the possible cause for this enigmatic event. (3) The compact radio emission which we tracked in the pre-CL (2014), during CL (2018) and post-CL(2021) at spatial scales $<1$ pc was at its lowest level during the changing look event in 2018, nearly contemporaneous with a low $2-10$ keV emission. The radio to X-ray ratio of the compact source $L_{\mathrm{Radio}}/L_{\mathrm{X}-\mathrm{ray}}\sim 10^{-5.5}$, follows the Gudel-Benz relation, typically found in coronally active stars, and several AGN. (4) We do not detect any presence of nascent jets at the spatial scales of $\sim 5-10$ pc.

arXiv commentResubmitted to ApJ following minor comments from the referee

References in corpus (65)

• Correcting for the Effects of Interstellar Extinction
• The Swift X-ray Telescope
• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• The Host Galaxies and Classification of Active Galactic Nuclei
• The Swift Ultra-Violet/Optical Telescope
• Local Supermassive Black Holes, Relics of Active Galactic Nuclei and the X-ray Background
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• Improved Reflection Models of Black-Hole Accretion Disks: Treating the Angular Distribution of X-rays
• The XMM-Newton Optical/UV Monitor Telescope
• Intrinsic disc emission and the Soft X-ray Excess in AGN
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• The X-ray to optical-UV luminosity ratio of X-ray selected Type 1 AGN in XMM-COSMOS
• Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies
• The corona contracts in a black-hole transient
• A global look at X-ray time lags in Seyfert Galaxies
• Interferometric Imaging Directly with Closure Phases and Closure Amplitudes
• The tight relation between X-ray and ultraviolet luminosity of quasars
• On the origin of radio emission in radio quiet quasars
• AGN Type-casting: Mrk 590 No Longer Fits the Role
• 1ES 1927+654: An AGN Caught Changing Look on a Timescale of Months
• The Parsec-scale Radio Structure of NGC 1068 and the Nature of the Nuclear Radio Source
• Ionized outflows from active galactic nuclei as the essential elements of feedback
• Unabsorbed Seyfert 2 galaxies
• Warm absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert galaxies: I. A global view and frequency of occurrence of warm absorbers
• The destruction and recreation of the X-ray corona in a changing-look Active Galactic Nucleus
• Driving extreme variability: The evolving corona and evidence for jet launching in Markarian 335
• Radio Variability of Radio Quiet and Radio Loud Quasars
• The Soft-Excess in Mrk 509: Warm Corona or Relativistic Reflection?
• Tidal disruption events in active galactic nuclei
• The WISSH Quasars Project III. X-ray properties of hyper-luminous quasars
• Radio Variability in Seyfert Nuclei
• Flaring from the supermassive black hole in Mrk 335 studied with Swift and NuSTAR
• The Close AGN Reference Survey (CARS) - What is causing Mrk1018's return to the shadows after 30 years?
• A remarkable long-term light curve, and deep, low-state spectroscopy: Swift & XMM-Newton monitoring of the NLS1 galaxy Mkn 335
• The Bologna Complete Sample of Nearby Radio Sources
• Indecent Exposure in Seyfert 2 Galaxies: A Close Look
• The 450 days X-ray monitoring of the changing-look AGN 1ES 1927+654
• Eleven years of monitoring the Seyfert 1 Mrk 335 with Swift: Characterizing the X-ray and UV/optical variability
• Transient jet formation and state transitions from large-scale magnetic reconnection in black hole accretion discs
• Simultaneous X-ray and optical observations of true Type 2 Seyfert galaxies
• Magnetic flux inversion in a peculiar changing look AGN
• NuSTAR/XMM-Newton monitoring of the Seyfert 1 galaxy HE 1143-1810. Testing the two-corona scenario
• Evidence for an emerging disc wind and collimated outflow during an X-ray flare in the narrow-line Seyfert 1 galaxy Mrk 335
• The Changing-Look Quasar Mrk 590 is Awakening
• The variable and non-variable X-ray absorbers in Compton-thin type-II Active Galactic Nuclei
• HST unveils a compact mildly relativistic Broad Line Region in the candidate true type 2 NGC 3147
• Star formation in self-gravitating disks in active galactic nuclei. II. Episodic formation of broad line regions
• 1ES 1927+654: Persistent and rapid X-ray variability in an AGN with low intrinsic neutral X-ray absorption and narrow optical emission lines
• 1ES 1927+654: a bare Seyfert 2
• X-ray warm absorption and emission in the polar scattered Seyfert 1 galaxy MRK 704
• Long-term optical, UV, and X-ray continuum variations in the changing-look AGN HE 1136-2304
• An X-ray view of central engines of low luminosity quasars (LLQSO) in the local Universe
• Tracking the year-to-year variation in the spectral energy distribution of the Narrow-line Seyfert 1 Galaxy Mrk335
• The effect of UV/Soft X-ray excess emission on the warm absorber properties of Active Galactic Nuclei -- A case study of IRAS 13349+2438
• Daily variability at milli-arcsecond scales in the radio quiet NLSy1 Mrk 110
• The nature of the soft-excess and spectral variability in the Seyfert 1 galaxy Zw 229.015
• A broadband X-ray spectral study of the Seyfert 1 galaxy ESO 141--G055 with XMM-Newton and NuSTAR
• Multi-epoch X-ray spectral analysis of the narrow-line Seyfert 1 galaxy Mrk 478
• A parsec-scale faint jet in the nearby changing-look Seyfert galaxy Mrk 590
• Exploring the spectral variability of the Seyfert 1.5 galaxy Markarian 530 with Suzaku
• Investigating the origin of the Fe emission lines of the Seyfert 1 galaxy Mrk~205
• On the origin of the featureless soft X-ray excess emission from the Seyfert 1 galaxy ESO~198--G24
• A weakening Compton hump and soft X-ray excess detected in the Seyfert-1 galaxy MCG-02-58-22

Cited by in corpus (5)

• Evolution of a Relativistic Outflow and X-ray Corona in the Extreme Changing-Look AGN 1ES 1927+654
• Chandra, HST/STIS, NICER, Swift, and TESS Detail the Flare Evolution of the Repeating Nuclear Transient ASASSN-14ko
• The outburst of the changing-look AGN IRAS23226-3843 in 2019
• Multiple Flares in the Changing-Look AGN NGC 5273
• Quantum contribution to luminosity of quasars