The population of tidal disruption events discovered with eROSITA

Abstract

This paper presents a systematic study of X-ray-selected canonical tidal disruption events (TDEs) discovered in the western Galactic hemisphere of the first two eROSITA all-sky surveys (eRASS1 and eRASS2) performed between Dec 2019 and Dec 2020. We compiled a TDE sample from the catalog of eROSITA's extragalactic transients and variables eRO-ExTra, which includes X-ray sources with a variability significance and fractional amplitude over four between eRASS1 and eRASS2, not associated with known AGNs. Each X-ray source is associated with an optical counterpart from the Legacy Survey DR10. Canonical TDEs were selected based on their X-ray light-curve properties (single flare or decline), soft X-ray spectra ($\Gamma >3$), and the absence of archival X-ray variability and AGN signatures in their host photometry and spectroscopy. The sample includes 31 X-ray-selected TDE candidates with redshifts of $0.02<z<0.34$ and luminosities of $5.7\times 10^{41}<L_X<5.3\times 10^{44}$ erg/s in the 0.2-6.0 keV rest frame, of which 30 are canonical TDEs and one is an off-nuclear TDE candidate. The derived X-ray luminosity function is best fit by a double power law with a luminosity break at $10^{44}$ erg/s, corresponding to the Eddington-limiting prediction. This corresponds to a TDE volumetric rate of $(2.3_{-0.9}^{+1.2})\times 10^{-7}Mp{c}^{-3}y{r}^{-1}$ ($\approx 1.2\times 10^{-5}$ events per galaxy per year). TDE host galaxies show a green-valley overdensity. In addition, 20%, 30%, and 15% of the sample exhibit flares in the optical, mid-infrared (mid-IR), or radio bands, respectively. We discuss the differences between X-ray, optical, and mid-IR TDE populations and the origins of multiwavelength flares in the context of the obscuring envelope and stream-stream collision models. Finally, we highlight TDE subpopulations that are not included in the canonical sample and should be explored in the future.

arXiv comment23 pages, 12 figures. Accepted for publication in A&A. Added a reference

References in corpus (95)

• emcee: The MCMC Hammer
• Planck 2015 results. XIII. Cosmological parameters
• Galactic Stellar and Substellar Initial Mass Function
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• The Swift X-ray Telescope
• The Optical and Near-Infrared Properties of Galaxies: I. Luminosity and Stellar Mass Functions
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• Overview of the DESI Legacy Imaging Surveys
• X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• ATLAS: A High-Cadence All-Sky Survey System
• The propagation of uncertainties in stellar population synthesis modeling III: model calibration, comparison, and evaluation
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Preliminary Results from NEOWISE: An Enhancement to the Wide-field Infrared Survey Explorer for Solar System Science
• The eROSITA X-ray telescope on SRG
• Relations Between Central Black Hole Mass and Total Galaxy Stellar Mass in the Local Universe
• Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS
• Stellar Population Inference with Prospector
• Discovery of the Onset of Rapid Accretion by a Dormant Massive Black Hole
• Optical Flares from the Tidal Disruption of Stars by Massive Black Holes
• A Continuum of H- to He-Rich Tidal Disruption Candidates With a Preference for E+A Galaxies
• Tidal Disruption Events
• Swift J2058.4+0516: Discovery of a Possible Second Relativistic Tidal Disruption Flare?
• The SRG X-ray orbital observatory, its telescopes and first scientific results
• Rates of Stellar Tidal Disruption as Probes of the Supermassive Black Hole Mass Function
• Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies
• The SRG/eROSITA all-sky survey: First X-ray catalogues and data release of the western Galactic hemisphere
• A unified model for tidal disruption events
• The eROSITA Final Equatorial Depth Survey (eFEDS): The X-ray catalog
• Multiband lightcurves of tidal disruption events
• PS1-10jh: The Disruption of a Main-Sequence Star of Near-Solar Composition
• The first XMM-Newton slew survey catalogue: XMMSL1
• The Ultraviolet-Optical Color-Magnitude Diagram III: Constraints on Evolution from the Blue to Red Sequence
• The Rapid ASKAP Continuum Survey I: Design and First Results
• A Bright Year for Tidal Disruptions?
• Optical Appearance of the Debris of a Star Disrupted by a Massive Black Hole
• A catalog of bulge, disk, and total stellar mass estimates for the Sloan Digital Sky Survey
• Large-Amplitude X-ray Outbursts from Galactic Nuclei: A Systematic Survey Using ROSAT Archival Data
• Tidal Disruption Events Prefer Unusual Host Galaxies
• The X-ray through Optical Fluxes and Line Strengths of Tidal Disruption Events
• Optical-Ultraviolet Tidal Disruption Events
• Finding counterparts for All-sky X-ray surveys with Nway: a Bayesian algorithm for cross-matching multiple catalogues
• Evolution of tidal disruption candidates discovered by XMM-Newton
• The destruction and recreation of the X-ray corona in a changing-look Active Galactic Nucleus
• Black hole masses of tidal disruption event host galaxies
• Prompt Radiation and Mass Outflows from the Stream-Stream Collisions of Tidal Disruption Events
• Soft X-ray Temperature Tidal Disruption Events from Stars on Deep Plunging Orbits
• X-ray Brightening and UV Fading of Tidal Disruption Event ASASSN-15oi
• Gaia Photometric Science Alerts
• The Host Galaxies of Tidal Disruption Events
• The eROSITA Final Equatorial-Depth Survey (eFEDS): Identification and characterization of the counterparts to the point-like sources
• The WISE Detection of an Infrared Echo in Tidal Disruption Event ASASSN-14li
• Tidal Disruption Event Host Galaxies in the Context of the Local Galaxy Population
• Partial Stellar Disruption by a Supermassive Black Hole: Is the Lightcurve Really Proportional to $t^{-9/4}$?
• Long-term stream evolution in tidal disruption events
• TDE Hosts are Green and Centrally Concentrated: Signatures of a Post-Merger System
• Disk Winds as an Explanation for Slowly Evolving Temperatures in Tidal Disruption Events
• Live to die another day: the rebrightening of AT2018fyk as a repeating partial tidal disruption event
• Infrared emission from tidal disruption events --- probing the pc-scale dust content around galactic nuclei
• An enhanced rate of tidal disruptions in the centrally overdense E+A galaxy NGC 3156
• Enhanced activity of massive black holes by stellar capture assisted by a self-gravitating accretion disc
• Deciphering the extreme X-ray variability of the nuclear transient eRASSt J045650.3-203750: A likely repeating partial tidal disruption event
• Rapid accretion state transitions following the tidal disruption event AT2018fyk
• Long-term X-ray variability of Swift J1644+57
• Radio and X-ray observations of the luminous Fast Blue Optical Transient AT2020xnd
• The Rapid ASKAP Continuum Survey IV: continuum imaging at 1367.5 MHz and the first data release of RACS-mid
• The NICER "Reverberation Machine": A Systematic Study of Time Lags in Black Hole X-Ray Binaries
• Tidal disruption rate of stars by supermassive black holes obtained by direct N-body simulations
• The UV/optical peak and X-ray brightening in TDE candidate AT2019azh: A case of stream-stream collision and delayed accretion
• Reverberation in tidal disruption events: dust echoes, coronal emission lines, multi-wavelength cross-correlations, and QPOs
• MUSE Reveals a Recent Merger in the Post-starburst Host Galaxy of the TDE ASASSN-14li
• The rebrightening of a ROSAT-selected tidal disruption event: repeated weak partial disruption flares from a quiescent galaxy?
• Discovery of a Mid-infrared Echo from the TDE candidate in the nucleus of ULIRG F01004-2237
• AT 2019avd: A novel addition to the diverse population of nuclear transients
• A radio-emitting outflow produced by the tidal disruption event AT2020vwl
• Stellar tidal disruption candidates found by cross-correlating the ROSAT Bright Source Catalogue and XMM-Newton observations
• XZ: Deriving redshifts from X-ray spectra of obscured AGN
• AT2019 avd: A tidal disruption event with a two-phase evolution
• Optical line spectra of tidal disruption events from reprocessing in optically thick outflows
• Rapid evolution of the recurrence time in the repeating partial tidal disruption event eRASSt J045650.3-203750
• Discovery of the luminous X-ray ignition eRASSt J234402.9$-$352640; I. Tidal disruption event or a rapid increase in accretion in an active galactic nucleus?
• Partial stellar tidal disruption events and their rates
• Forward Modeling Populations of Flares from Tidal Disruptions of Stars by Super-massive Black Holes
• X-Ray Emission from Star-Forming Galaxies - Signatures of Cosmic Rays and Magnetic Fields
• The radio detection and accretion properties of the peculiar nuclear transient AT 2019avd
• Stellar and gas dynamical model for tidal disruption events in a quiescent galaxy
• Gamma-Ray Bursts
• eRASSt J074426.3+291606: prompt accretion disc formation in a 'faint and slow' tidal disruption event
• CircleZ: Reliable Photometric redshifts for AGN computed using only photometry from Legacy Survey Imaging for DESI
• A maximum X-ray luminosity scale of disc-dominated tidal disruption events
• eRO-ExTra: eROSITA extragalactic non-AGN X-ray transients and variables in eRASS1 and eRASS2

Cited by in corpus (7)

• Counterpart identification and classification for eRASS1 and characterisation of the AGN content
• eROSITA-RU Tidal Disruption Events with Keck-I/LRIS: Sample Selection, Optical Properties, and Host Galaxy Demographics
• A new Bowen Fluorescence Flare and Extreme Coronal Line Emitter discovered by SRG/eROSITA
• TDE 2025abcr: A Tidal Disruption Event in the Outskirts of a Massive Galaxy
• Wind-mediated Eddington-limited emission in a $10^4{M}_{\odot }$ Black Hole Tidal Disruption Event
• Rate of Repeating Tidal Disruption Events with 5--19 years interval
• Early results in the search for extreme coronal line emitters with the Dark Energy Spectroscopic Instrument