Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk
Following a tidal disruption event (TDE), the accretion rate can evolve from quiescent to near-Eddington levels and back over timescales of months to years. This provides a unique opportunity to study the formation and evolution of the accretion flow around supermassive black holes (SMBHs). We prese...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Journal Article |
| Language: | English |
| Published: |
IOP Publishing Ltd
2021
|
| Subjects: | |
| Online Access: | http://purl.org/au-research/grants/arc/DP200102471 http://hdl.handle.net/20.500.11937/90030 |
| _version_ | 1848765314541551616 |
|---|---|
| author | Wevers, T. Pasham, D.R. Van Velzen, S. Miller-Jones, James Uttley, P. Gendreau, K.C. Remillard, R. Arzoumanian, Z. Löwenstein, M. Chiti, A. |
| author_facet | Wevers, T. Pasham, D.R. Van Velzen, S. Miller-Jones, James Uttley, P. Gendreau, K.C. Remillard, R. Arzoumanian, Z. Löwenstein, M. Chiti, A. |
| author_sort | Wevers, T. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Following a tidal disruption event (TDE), the accretion rate can evolve from quiescent to near-Eddington levels and back over timescales of months to years. This provides a unique opportunity to study the formation and evolution of the accretion flow around supermassive black holes (SMBHs). We present 2 yr of multiwavelength monitoring observations of the TDE AT2018fyk at X-ray, UV, optical, and radio wavelengths. We identify three distinct accretion states and two state transitions between them. These appear remarkably similar to the behavior of stellar-mass black holes in outburst. The X-ray spectral properties show a transition from a soft (thermal-dominated) to a hard (power-law-dominated) spectral state around L bol ∼ few × 10-2 L Edd and the strengthening of the corona over time ∼100-200 days after the UV/optical peak. Contemporaneously, the spectral energy distribution (in particular, the UV to X-ray spectral slope α ox) shows a pronounced softening as the outburst progresses. The X-ray timing properties also show a marked change, initially dominated by variability at long (>day) timescales, while a high-frequency (∼10-3 Hz) component emerges after the transition into the hard state. At late times (∼500 days after peak), a second accretion state transition occurs, from the hard into the quiescent state, as identified by the sudden collapse of the bolometric (X-ray+UV) emission to levels below 10-3.4 L Edd. Our findings illustrate that TDEs can be used to study the scale (in)variance of accretion processes in individual SMBHs. Consequently, they provide a new avenue to study accretion states over seven orders of magnitude in black hole mass, removing limitations inherent to commonly used ensemble studies. |
| first_indexed | 2025-11-14T11:33:17Z |
| format | Journal Article |
| id | curtin-20.500.11937-90030 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:33:17Z |
| publishDate | 2021 |
| publisher | IOP Publishing Ltd |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-900302023-02-07T06:36:37Z Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk Wevers, T. Pasham, D.R. Van Velzen, S. Miller-Jones, James Uttley, P. Gendreau, K.C. Remillard, R. Arzoumanian, Z. Löwenstein, M. Chiti, A. Science & Technology Physical Sciences Astronomy & Astrophysics ACTIVE GALACTIC NUCLEI X-RAY BINARIES BLACK-HOLE MASSES FUNDAMENTAL PLANE POWER SPECTRA COMPACT JET STELLAR EVOLUTION VARIABILITY AGN Following a tidal disruption event (TDE), the accretion rate can evolve from quiescent to near-Eddington levels and back over timescales of months to years. This provides a unique opportunity to study the formation and evolution of the accretion flow around supermassive black holes (SMBHs). We present 2 yr of multiwavelength monitoring observations of the TDE AT2018fyk at X-ray, UV, optical, and radio wavelengths. We identify three distinct accretion states and two state transitions between them. These appear remarkably similar to the behavior of stellar-mass black holes in outburst. The X-ray spectral properties show a transition from a soft (thermal-dominated) to a hard (power-law-dominated) spectral state around L bol ∼ few × 10-2 L Edd and the strengthening of the corona over time ∼100-200 days after the UV/optical peak. Contemporaneously, the spectral energy distribution (in particular, the UV to X-ray spectral slope α ox) shows a pronounced softening as the outburst progresses. The X-ray timing properties also show a marked change, initially dominated by variability at long (>day) timescales, while a high-frequency (∼10-3 Hz) component emerges after the transition into the hard state. At late times (∼500 days after peak), a second accretion state transition occurs, from the hard into the quiescent state, as identified by the sudden collapse of the bolometric (X-ray+UV) emission to levels below 10-3.4 L Edd. Our findings illustrate that TDEs can be used to study the scale (in)variance of accretion processes in individual SMBHs. Consequently, they provide a new avenue to study accretion states over seven orders of magnitude in black hole mass, removing limitations inherent to commonly used ensemble studies. 2021 Journal Article http://hdl.handle.net/20.500.11937/90030 10.3847/1538-4357/abf5e2 English http://purl.org/au-research/grants/arc/DP200102471 http://creativecommons.org/licenses/by/4.0/ IOP Publishing Ltd fulltext |
| spellingShingle | Science & Technology Physical Sciences Astronomy & Astrophysics ACTIVE GALACTIC NUCLEI X-RAY BINARIES BLACK-HOLE MASSES FUNDAMENTAL PLANE POWER SPECTRA COMPACT JET STELLAR EVOLUTION VARIABILITY AGN Wevers, T. Pasham, D.R. Van Velzen, S. Miller-Jones, James Uttley, P. Gendreau, K.C. Remillard, R. Arzoumanian, Z. Löwenstein, M. Chiti, A. Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk |
| title | Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk |
| title_full | Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk |
| title_fullStr | Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk |
| title_full_unstemmed | Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk |
| title_short | Rapid Accretion State Transitions following the Tidal Disruption Event AT2018fyk |
| title_sort | rapid accretion state transitions following the tidal disruption event at2018fyk |
| topic | Science & Technology Physical Sciences Astronomy & Astrophysics ACTIVE GALACTIC NUCLEI X-RAY BINARIES BLACK-HOLE MASSES FUNDAMENTAL PLANE POWER SPECTRA COMPACT JET STELLAR EVOLUTION VARIABILITY AGN |
| url | http://purl.org/au-research/grants/arc/DP200102471 http://hdl.handle.net/20.500.11937/90030 |