Chandra, HST/STIS, NICER, Swift, and TESS Detail the Flare Evolution of the Repeating Nuclear Transient ASASSN-14ko

Payne, A. V.; Auchettl, Katie; Shappee, B. J.; Kochanek, C. S.; Boyd, Patricia T.; Holoien, Thomas W. -S.; Fausnaugh, Michael; Ashall, C.; Hinkle, J.; Vallely, P.; Z., Stanek, K.; Thompson, Todd A.

doi:10.48550/arxiv.2206.11278

Cited by 3 publications

(4 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to studying supernovae (SNe; e.g., Bose et al 2018Bose et al , 2019Hoeflich et al 2021;Chen et al 2022), ASAS-SN obtains data for a broad range of transients, multi-messenger searches, and variable sources. For transients, these include tidal disruption events (TDEs; e.g., Holoien et al 2019b,c, 2020, Hinkle et al 2021, Payne et al 2022, novae (e.g., Kawash et al 2021bKawash et al , 2022, dwarf novae (e.g., Kawash et al 2021a), and changing look or other active galactic nuclei (AGN; e.g., Neustadt et al 2020, Hinkle et al 2022, Holoien et al 2022. There are multi-messenger searches associated with both neutrino (e.g., IceCube Collaboration et al 2018, Necker et al 2022) and gravitational wave (e.g., de Jaeger et al 2022) events.…”

mentioning

confidence: 99%

The ASAS-SN bright supernova catalogue – V. 2018–2020

Neumann

Holoien

Kochanek

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We catalog the 443 bright supernovae discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) in 2018 − 2020 along with the 519 supernovae recovered by ASAS-SN and 516 additional mpeak ≤ 18 mag supernovae missed by ASAS-SN. Our statistical analysis focuses primarily on the 984 supernovae discovered or recovered in ASAS-SN g-band observations. The complete sample of 2427 ASAS-SN supernovae includes earlier V-band samples and unrecovered supernovae. For each supernova, we identify the host galaxy, its UV to mid-IR photometry, and the supernova’s offset from the center of the host. Updated peak magnitudes, redshifts, spectral classifications, and host galaxy identifications supersede earlier results. With the increase of the limiting magnitude to g ≤ 18 mag, the ASAS-SN sample is nearly complete up to mpeak = 16.7 mag and is $90{{\%}}$ complete for mpeak ≤ 17.0 mag. This is an increase from the V-band sample where it was roughly complete up to mpeak = 16.2 mag and $70{{\%}}$ complete for mpeak ≤ 17.0 mag.

show abstract

mentioning

confidence: 99%

The ASAS-SN bright supernova catalogue – V. 2018–2020

Neumann

Holoien

Kochanek

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…However, when the delay due to circularization is comparable to the fallback timescale, the resulting TDE light curve will be drastically flattened (Mockler et al 2019), resulting in a much shallower rise in luminosity than the one observed in ASASSN-14ko. In addition, the bright, fast evolving X-ray emission in ASASSN-14ko (Payne et al 2022a(Payne et al , 2022b) also indicates efficient disk formation. Hence, for ASASSN-14ko, the circularization delay and the viscous timescale are both expected to be negligible.…”

Section: Constraints On the Mean Stellar Densitymentioning

confidence: 99%

“…where κ T is the Thomson opacity for electron scattering, M env ≈ ΔM is the mass of the outflow, and r in and r out are the inner and outer radius of the wind. Payne et al (2022a) estimated the blackbody radius of the photosphere during a single flare using UV data, which expands from 10 14.2 -10 14.9 cm as the luminosity rises to its maximum. This means r in of the reprocessing layer where the wind originates is 10 14.2 cm and r out ≈ 10 14.9 cm when the UV luminosity reaches its peak value.…”

Section: Constraints On the Stellar Massmentioning

confidence: 99%

Tidal Disruption Events from Eccentric Orbits and Lessons Learned from the Noteworthy ASASSN-14ko

Liu

Mockler

Ramírez-Ruiz

et al. 2023

ApJ

View full text Add to dashboard Cite

Stars grazing supermassive black holes (SMBHs) on bound orbits may survive tidal disruption, causing periodic flares. Inspired by the recent discovery of the periodic nuclear transient ASASSN-14ko, a promising candidate for a repeating tidal disruption event (TDE), we study the tidal deformation of stars approaching SMBHs on eccentric orbits. With both analytical and hydrodynamic methods, we show the overall tidal deformation of a star is similar to that in a parabolic orbit provided that the eccentricity is above a critical value. This allows one to make use of existing simulation libraries from parabolic encounters to calculate the mass fallback rate in eccentric TDEs. We find the flare structures of eccentric TDEs show a complicated dependence on both the SMBH mass and the orbital period. For stars orbiting SMBHs with relatively short periods, we predict significantly shorter-lived duration flares than those in parabolic TDEs, which can be used to predict repeating events if the mass of the SMBH can be independently measured. Using an adiabatic mass-loss model, we study the flare evolution over multiple passages, and show the evolved stars can survive many more passages than main-sequence stars. We apply this theoretical framework to the repeating TDE candidate ASASSN-14ko and suggest that its recurrent flares originate from a moderately massive (M ≳ 1 M ⊙), extended (likely ≈10 R ⊙), evolved star on a grazing, bound orbit around the SMBH. Future hydrodynamic simulations of multiple tidal interactions will enable realistic models on the individual flare structure and the evolution over multiple flares.

show abstract

“…Additionally, several other nuclear transients have had rise slopes measured with TESS, with flatter rises than these TDEs. These include the repeating TDE ASASSN-14ko, with a rise slope of α = 1.01 ± 0.07 (51) for the first flare observed by TESS when assuming a single power-law model, and α = 1.10 ± 0.04 and α = 1.50 ± 0.10 for the first and the second flares observed by TESS, respectively, when assuming a curved power-law model (88), and the ANT ASASSN-20hx, with a rise slope of α = 1.05 ± 0.06 (89).…”

Section: Tessmentioning

confidence: 99%

A Case for a Binary Black Hole System Revealed via Quasi-Periodic Outflows

Pasham¹,

Tombesi

Suková

et al. 2022

Preprint

View full text Add to dashboard Cite

Binary black hole systems in close orbits are thought to be the precursors of gravitational wave events and their identification has fundamental implications for our understanding of black hole growth and evolution. However, a gravitationally bound companion orbiting closer than about a milli-parsec to an accreting supermassive black hole (SMBH, mass ≥106 solar masses) in an external galaxy cannot be spatially resolved with present-day instruments. Instead, its detection requires a combination of indirect observational methods and advanced modelling. Here we report the detection of quasi-periodic variability in X-ray spectral features after an outburst from a previously low-luminosity Active Galactic Nucleus (AGN) in a galaxy at redshift z=0.056. We interpret this variability as due to Quasi-Periodic Outflows (QPOuts) from the SMBH. The puzzling phenomenon repeats roughly once every 8.5 days and photo-ionization modeling of the energy spectra implies that the outflowing material moves with a high velocity of about a third of the speed of light. The mass of the central black hole, roughly 30 million solar masses, as derived from the optical broad line--SMBH mass scaling relation, implies that the outflows are launched from a few tens of gravitational radii from the SMBH event horizon. By performing 2D and 3D general relativistic magnetohydrodynamic (GRMHD) simulations and by comparing their results over a broad range of the system parameters we show that these QPOuts can be explained with an orbiting intermediate-mass black hole (IMBH) secondary (mass range of 100--10,000 solar masses) at a distance of about 100 gravitational radii (less than a milli-parsec) from the primary SMBH. Outflows are naturally enhanced when the secondary object punches through the SMBH's inner accretion disc during each orbital period and this is revealed as regular increases in X-ray absorption along our line of sight. The overall optical, UV and X-ray outburst properties indicate that a major accretion episode -- perhaps from a stellar tidal disruption by the SMBH -- could have provided the gas to illuminate the presence of the pre-existing IMBH secondary. Our work highlights the new astrophysical phenomenon of QPOuts and the importance of high cadence X-ray monitoring observations to potentially uncover electromagnetic signatures of such tight binary black hole systems.

show abstract

Chandra, HST/STIS, NICER, Swift, and TESS Detail the Flare Evolution of the Repeating Nuclear Transient ASASSN-14ko

Cited by 3 publications

References 68 publications

The ASAS-SN bright supernova catalogue – V. 2018–2020

The ASAS-SN bright supernova catalogue – V. 2018–2020

Tidal Disruption Events from Eccentric Orbits and Lessons Learned from the Noteworthy ASASSN-14ko

A Case for a Binary Black Hole System Revealed via Quasi-Periodic Outflows

Contact Info

Product

Resources

About