Distinguishing Tidal Disruption Events from Impostors

Abstract

Recent claimed detections of tidal disruption events (TDEs) in multi-wavelength data have opened potential new windows into the evolution and properties of otherwise dormant supermassive black holes (SMBHs) in the centres of galaxies. At present, there are several dozen TDE candidates, which share some properties and differ in others. The range in properties is broad enough to overlap other transient types, such as active galactic nuclei (AGN) and supernovae (SNe), which can make TDE classification ambiguous. A further complication is that "TDE signatures" have not been uniformly observed to similar sensitivities or even targeted across all candidates. This chapter reviews those events that are unusual relative to other TDEs, including the possibility of TDEs in pre-existing AGN, and summarises those characteristics thought to best distinguish TDEs from continuously accreting AGN, strongly flaring AGN, SNe, and Gamma-Ray Bursts (GRBs), as well as other potential impostors like stellar collisions, "micro-TDEs," and circumbinary accretion flows. We conclude that multiple observables should be used to classify any one event as a TDE. We also consider the TDE candidate population as a whole, which, for certain host galaxy or SMBH characteristics, is distinguishable statistically from non-TDEs, suggesting that at least some TDE candidates do in fact arise from SMBH-disrupted stars.

arXiv comment57 pages, 17 figures. Accepted for publication in Springer Space Science Reviews. Chapter in ISSI review "The Tidal Disruption of Stars by Massive Black Holes" vol. 79. Corrected several typos from previous submission

References in corpus (182)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• The Host Galaxies of AGN
• The Host Galaxies and Classification of Active Galactic Nuclei
• Composite Quasar Spectra From the Sloan Digital Sky Survey
• A Catalog of Quasar Properties from SDSS DR7
• The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III
• Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS
• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• Luminous Supernovae
• A relativistic jetted outburst from a massive black hole fed by a tidally disrupted star
• Discovery of the Onset of Rapid Accretion by a Dormant Massive Black Hole
• The Chandra Deep Field-South Survey: 4 Ms Source Catalogs
• What Drives the Growth of Black Holes?
• Hydrogen-poor superluminous stellar explosions
• Hydrodynamical Simulations to Determine the Feeding Rate of Black Holes by the Tidal Disruption of Stars: The Importance of the Impact Parameter and Stellar Structure
• A Decade of Short-duration Gamma-ray Burst Broad-band Afterglows: Energetics, Circumburst Densities, and Jet Opening Angles
• Optical Flares from the Tidal Disruption of Stars by Massive Black Holes
• Black Hole Mass and Eddington Ratio as Drivers for the Observable Properties of Radio-Loud and Radio-Quiet QSOs
• The Ensemble Photometric Variability of ~25000 Quasars in the Sloan Digital Sky Survey
• V1309 Scorpii: merger of a contact binary
• An ultraviolet-optical flare from the tidal disruption of a helium-rich stellar core
• A Continuum of H- to He-Rich Tidal Disruption Candidates With a Preference for E+A Galaxies
• Secular evolution of compact binaries near massive black holes: gravitational wave sources and other exotica
• The Birth of a Relativistic Outflow in the Unusual γ-ray Transient Swift J164449.3+573451
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• Massive black hole binary mergers within sub-pc scale gas discs
• An Eccentric Circumbinary Accretion Disk and the Detection of Binary Massive Black Holes
• Swift J2058.4+0516: Discovery of a Possible Second Relativistic Tidal Disruption Flare?
• X-ray spectral properties of AGN in the Chandra Deep Field South
• Two ten-billion-solar-mass black holes at the centres of giant elliptical galaxies
• Star formation rate indicators in the Sloan Digital Sky Survey
• Nuclear Star Clusters
• Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies
• A unified model for tidal disruption events
• Optical discovery of probable stellar tidal disruption flares
• The Distance to SN 1999em in NGC 1637 from the Expanding Photosphere Method
• Multiband lightcurves of tidal disruption events
• Six Months of Multi-Wavelength Follow-up of the Tidal Disruption Candidate ASASSN-14li and Implied TDE Rates from ASAS-SN
• A Description of Quasar Variability Measured Using Repeated SDSS and POSS Imaging
• Caltech Core-Collapse Project (CCCP) observations of type IIn supernovae: typical properties and implications for their progenitor stars
• A new population of ultra-long duration gamma-ray bursts
• Three Dimensional MHD Simulation of Circumbinary Accretion Disks: Disk Structures and Angular Momentum Transport
• Accretion into the Central Cavity of a Circumbinary Disk
• On the triple origin of blue stragglers
• The Relationship of Hard X-ray and Optical Line Emission in Low Redshift Active Galactic Nuclei
• The evolution of a supermassive binary caused by an accretion disc
• The Nature of LINER-like Emission in Red Galaxies
• ASASSN-14ae: A Tidal Disruption Event at 200 Mpc
• The Quest for Dual and Binary Supermassive Black Holes: A Multi-Messenger View
• New physical insights about Tidal Disruption Events from a comprehensive observational inventory at X-ray wavelengths
• Changing look: from Compton-thick to Compton-thin, or the re-birth of fossil AGN
• Explaining changing-look AGN with state transition triggered by rapid mass accretion rate drop
• Weighing Black Holes using Tidal Disruption Events
• The Superluminous Transient ASASSN-15lh as a Tidal Disruption Event from a Kerr Black Hole
• Luminous Thermal Flares from Quiescent Supermassive Black Holes
• What the Optical Recombination Lines Can Tell Us About the Broad Line Regions of Active Galactic Nuclei
• Dusty Structure Around Type-I Active Galactic Nuclei: Clumpy Torus Narrow Line Region and Near-Nucleus Hot Dust
• Consequences of Strong Compression in Tidal Disruption Events
• Tidal Disruption Events Prefer Unusual Host Galaxies
• Flows of X-ray gas reveal the disruption of a star by a massive black hole
• A Near-Infrared Spectral Template for Quasars
• Size and Structure of the Narrow-Line Region of Quasars
• ASASSN-15lh: A Highly Super-Luminous Supernova
• The UV-bright, Slowly Declining Transient PS1-11af as a Partial Tidal Disruption Event
• The first month of evolution of the slow rising type II-P SN 2013ej in M74
• The Structure of the Broad Line Region in AGN: I. Reconstructed Velocity-Delay Maps
• Optical-Ultraviolet Tidal Disruption Events
• PS16dtm: A Tidal Disruption Event in a Narrow-line Seyfert 1 Galaxy
• 1ES 1927+654: An AGN Caught Changing Look on a Timescale of Months
• A Hubble Space Telescope Survey of Extended [OIII]5007A Emission in a Far-Infrared Selected Sample of Seyfert Galaxies: Results
• A Hubble Space Telescope Survey of Extended [OIII]5007A Emission in a Far-Infrared Selected Sample of Seyfert Galaxies: Observations
• ASASSN-15oi: A Rapidly Evolving, Luminous Tidal Disruption Event at 216 Mpc
• Quasars Are Not Light-Bulbs: Testing Models of Quasar Lifetimes with the Observed Eddington Ratio Distribution
• A tidal disruption flare in a massive galaxy? Implications for the fuelling mechanisms of nuclear black holes
• The destruction and recreation of the X-ray corona in a changing-look Active Galactic Nucleus
• Revisiting optical tidal disruption events with iPTF16axa
• Black hole masses of tidal disruption event host galaxies
• Radio Monitoring of the Tidal Disruption Event Swift J164449.3+573451. II. The Relativistic Jet Shuts Off and a Transition to Forward Shock X-ray/Radio Emission
• On the mass and luminosity functions of tidal disruption flares: rate suppression due to black hole event horizons
• Towards an Understanding of Changing-Look Quasars: An Archival Spectroscopic Search in SDSS
• Evidence for rapid disk formation and reprocessing in the X-ray bright tidal disruption event AT 2018fyk
• A luminous X-ray outburst from an intermediate-mass black hole in an off-centre star cluster
• Late-time UV observations of tidal disruption flares reveal unobscured, compact accretion disks
• HST-COS Observations of AGN. I. Ultraviolet Composite Spectra of the Ionizing Continuum and Emission Lines
• Variability in black hole accretion discs
• Near Infrared Spectroscopy of High Redshift Active Galactic Nuclei. II. Disappearing Narrow Line Regions and the Role of Accretion
• Size and properties of the narrow-line region in Seyfert-1 galaxies from spatially-resolved optical spectroscopy
• X-ray Brightening and UV Fading of Tidal Disruption Event ASASSN-15oi
• Circumbinary Accretion from Finite and Infinite Disks
• The Host Galaxies of Tidal Disruption Events
• Radiation pressure instability driven variability in the accreting black holes
• Galaxy Mergers Drive Shocks: an Integral Field Study of GOALS galaxies
• The Size of the Narrow-Line Emitting Region in the Seyfert 1 Galaxy NGC 5548 from Emission-Line Variability
• Understanding extreme quasar optical variability with CRTS: I. Major AGN flares
• An outflow powers the optical rise of the nearby, fast-evolving tidal disruption event AT2019qiz
• The spectral evolution of AT 2018dyb and the presence of metal lines in tidal disruption events
• On the Thermal Stability of Radiation Dominated Accretion Disks
• AGN Obscuration and the Unified Model
• The Analogous Structure of Accretion Flows in Supermassive and Stellar Mass Black Holes: New Insights from Faded Changing-Look Quasars
• Optical variability of AGN in the PTF/iPTF survey
• On The Nature of Low Luminosity Narrow Line AGN
• A New Class of Changing-Look LINERs
• Rates of Stellar Tidal Disruption
• Tidal Disruption Event Host Galaxies in the Context of the Local Galaxy Population
• The Broad Absorption Line Tidal Disruption Event iPTF15af: Optical and Ultraviolet Evolution
• PS18kh: A New Tidal Disruption Event with a Non-Axisymmetric Accretion Disk
• A new class of flares from accreting supermassive black holes
• Black hole masses of tidal disruption event host galaxies II
• THE UNUSUAL X-RAY AND OPTICAL PROPERTIES OF THE ULTRASOFT AGN ZWICKY 159.034 (RE J 1237+264)
• Micro - tidal disruption events by stellar compact objects and the production of ultra-long GRBs
• A likely decade-long sustained tidal disruption event
• The Discovery and Nature of Optical Transient CSS100217:102913+404220
• A New Paradigm for Gamma Ray Bursts: Long Term Accretion Rate Modulation by an External Accretion Disk
• Indicators of Intrinsic AGN Luminosity: a Multi-Wavelength Approach
• Tidal disruption events in active galactic nuclei
• H-alpha Spectral diversity of type II supernovae
• A Multiwavelength Study of the Relativistic Tidal Disruption Candidate Sw J2058+05 at Late Times
• Ultrafast Outflow in Tidal Disruption Event ASASSN-14li
• The Fate of Binaries in the Galactic Center: The Mundane and the Exotic
• A dependence of the tidal disruption event rate on global stellar surface mass density and stellar velocity dispersion
• SALT Long-slit Spectroscopy of Luminous Obscured Quasars: An Upper Limit on the Size of the Narrow-Line Region?
• Secular Evolution Of Binaries Near Massive Black Holes: Formation of compact binaries, merger/collision products and G2-like objects
• IC 751: a new changing-look AGN discovered by NuSTAR
• What Sets the Line Profiles in Tidal Disruption Events?
• Red giant stellar collisions in the Galactic Centre
• NTT, Spitzer and Chandra spectroscopy of SDSSJ095209.56+214313.3: the most luminous coronal-line supernova ever observed, or a stellar tidal disruption event ?
• XMMSL1 J074008.2-853927: a tidal disruption event with thermal and non-thermal components
• X-ray spectral properties of the AGN sample in the northern XMM-XXL field
• A Remarkably Loud Quasi-Periodicity after a Star is Disrupted by a Massive Black Hole
• Implications from Late-Time X-ray Detections of Optically Selected Tidal Disruption Events: State Changes, Unification, and Detection Rates
• The evolution of large cavities and disc eccentricity in circumbinary discs
• Characteristic QSO Accretion Disk Temperatures from Spectroscopic Continuum Variability
• Evidence for Large Temperature Fluctuations in Quasar Accretion Disks From Spectral Variability
• An Ultraviolet Spectrum of the Tidal Disruption Flare ASASSN-14li
• A population of highly energetic transient events in the centres of active galaxies
• Comparison of the X-ray emission from Tidal Disruption Events with those of Active Galactic Nuclei
• The Ultraviolet Spectroscopic Evolution of the Low-Luminosity Tidal Disruption Event iPTF16fnl
• The Close AGN Reference Survey (CARS) - What is causing Mrk1018's return to the shadows after 30 years?
• Continuum-Fitting the X-ray Spectra of Tidal Disruption Events
• Gemini Long-slit Observations of Luminous Obscured Quasars: Further Evidence for an Upper Limit on the Size of the Narrow-Line Region
• Tidal break-up of binary stars at the Galactic center and its consequences
• AGN X-ray variability in the XMM-COSMOS survey
• The Long Term Evolution of ASASSN-14li
• Discovery of Highly Blueshifted Broad Balmer and Metastable Helium Absorption Lines in a Tidal Disruption Event
• Discovery of an Ultrasoft X-ray Transient Source in the 2XMM Catalog: a Tidal Disruption Event Candidate
• IC 3599 did it again: A second outburst of the X-ray transient Seyfert 1.9 Galaxy
• Multiple tidal disruption flares in the active galaxy IC 3599
• The Post-Starburst Evolution of Tidal Disruption Event Host Galaxies
• The Unusual Late-Time Evolution of the Tidal Disruption Event ASASSN-15oi
• The Clustering of High-Redshift (2.9 $\le$ z $\le$ 5.1) Quasars in SDSS Stripe 82
• X-rays from the location of the Bactrian Transient ASASSN-15lh
• The giant X-ray outbursts in NGC 5905 and IC 3599: Follow-up observations and outburst scenarios
• Evolution of the Fraction of Clumpy Galaxies at 0.2<z<1.0 in the COSMOS field
• GRB 110328A/Swift J164449.3+573451: The Tidal Obliteration of a Deeply Plunging Star?
• The Unexpected, Long-Lasting, UV Rebrightening of the Super-Luminous Supernova ASASSN-15lh
• Updating quasar bolometric luminosity corrections. II. Infrared bolometric corrections
• Simultaneous transverse and longitudinal oscillations in a quiescent prominence triggered by a coronal jet
• Recurring flares from supermassive black hole binaries: implications for tidal disruption candidates and OJ 287
• A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan Digital Sky Survey
• The Nature of the Giant Outbursts in the Bursting Pulsar GRO J 1744-28
• Late time multi wavelength observations of Swift J1644+5734: A luminous optical/IR bump and quiescent X-ray emission
• Was the soft X-ray flare in NGC 3599 due to an AGN disc instability or a delayed tidal disruption event?
• Simulations of galaxies formed in warm dark matter halos of masses at the filtering scale
• The supermassive black hole coincident with the luminous transient ASASSN-15lh
• Periodic accretion-powered flares from colliding EMRIs as TDE Imposters
• Optical follow-up of the tidal disruption event iPTF16fnl: new insights from X-shooter observations
• Discovery and Follow-up of the Unusual Nuclear Transient OGLE17aaj
• Insight Into "Changing-Look" AGN Mrk 1018 from the Fe K$\alpha$ Line: The Reprocessing Gas Has Yet to Fully Respond to the Fading of the AGN
• Updating quasar bolometric luminosity corrections. III. [O III] bolometric corrections
• Superluminous transients at AGN centers from interaction between black-hole disk winds and broad-line region clouds
• Tidal disruption by extreme mass ratio binaries and application to ASASSN-15lh
• Light curves of tidal disruption events in active galactic nuclei
• ASASSN-15lh: a TDE about a maximally rotating $10^9{M}_{\odot }$ black hole
• Extreme variability in an active galactic nucleus: Gaia16aax
• Spectral features of tidal-disruption candidates and alternative origins for such transient flares
• Gaia transients in galactic nuclei
• Tidal disruption of stars in a supermassive black hole binary system: the influence of orbital properties on fallback and accretion rates
• The GALEX Time Domain Survey. II. Wavelength-Dependent Variability of Active Galactic Nuclei in the Pan-STARRS1 Medium Deep Survey
• Gaia transient detection efficiency: hunting for nuclear transients
• Some statistical properties of spiral galaxies
• RX J1624.9+7554: A new X-ray transient AGN
• Emission line taxonomy and the nature of AGN-looking galaxies in the SDSS

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• Reverberation in tidal disruption events: dust echoes, coronal emission lines, multi-wavelength cross-correlations, and QPOs
• The rebrightening of a ROSAT-selected tidal disruption event: repeated weak partial disruption flares from a quiescent galaxy?
• After The Fall: Resolving the Molecular Gas in Post-Starburst Galaxies
• The nuclear transient AT 2017gge: a tidal disruption event in a dusty and gas-rich environment and the awakening of a dormant SMBH
• The rise and fall of the iron-strong nuclear transient PS16dtm
• Mid-InfraRed Outbursts in Nearby Galaxies (MIRONG). II. Optical Spectroscopic Follow-up
• Lightcurve Evolution of the nearest Tidal Disruption Event: A late-time, radio-only flare
• Searching for Ultra-light Bosons and Constraining Black Hole Spin Distributions with Stellar Tidal Disruption Events
• Recurring tidal disruption events a decade apart in IRAS F01004-2237
• Embers of Active Galactic Nuclei: Tidal Disruption Events and Quasiperiodic Eruptions
• The transient event in NGC 1566 from 2017 to 2019 -- I. An eccentric accretion disk and a turbulent, disk-dominated broad-line region unveiled by double-peaked Ca II and O I lines
• SDSS1335+0728: The awakening of a $\sim 10^6{M}_{\odot }$ black hole
• Discovery and Follow-up of ASASSN-23bd (AT 2023clx): The Lowest Redshift and Least Luminous Tidal Disruption Event To Date
• AT2018dyk Revisited: a Tidal Disruption Event Candidate with Prominent Infrared Echo and Delayed X-ray Emission in a LINER Galaxy
• The fall of CSS100217: a tidal disruption-induced low state in an apparently hostless active galactic nucleus
• The Simulated Catalogue of Optical Transients and Correlated Hosts (SCOTCH)
• The nascent milliquasar VT J154843.06+220812.6: tidal disruption event or extreme accretion-state change?
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• Linear and circular polarimetry of the optically bright relativistic Tidal Disruption Event AT 2022cmc
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• A Mid-infrared Flare in the Seyfert Galaxy NGC 3786: A Changing-look Event Triggered by an Obscured Tidal Disruption Event?
• X-ray Unveiling Events in a z~1.6 Active Galactic Nucleus in the 7 Ms Chandra Deep Field-South
• Unveiling the Cosmic Dance of Repeated Nuclear Transient ASASSN-14ko: Insights from Multiwavelength Observations
• Insights from the "Red devil" AT 2022fpx: A Dust-reddened Family of Tidal Disruption Events Excluded by Their Apparent Red Color?
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• Rates of Strongly Lensed Tidal Disruption Events
• Long-term Mid-infrared Color Variations of Narrow-Line Seyfert 1 Galaxies
• AT 2021hdr: A candidate tidal disruption of a gas cloud by a binary super massive black hole system
• Radio and X-ray flux rebrightening six years after outburst in a partially-obscured extreme changing-look AGN
• Rate of Repeating Tidal Disruption Events with 5--19 years interval