Candidate Tidal Disruption Event AT2019fdr Coincident with a High-Energy Neutrino

Reusch, Simeon; Stein, R.; Kowalski, M.; Velzen, S. van; Franckowiak, A.; Lunardini, Cecilia; Murase, Kohta; Winter, Walter; Miller-Jones, J. C. A.; Kasliwal, M. M.; Gilfanov, M.; Garrappa, S.; Paliya, Vaidehi S.; Ahumada, Tomás; Anand, Shreya; Barbarino, C.; Bellm, Eric C.; Brinnel, V.; Buson, S.; Cenko, S. B.; Coughlin, M. W.; De, Kishalay; Dekany, Richard; Frederick, Sara; Gal‐Yam, A.; Gezari, Suvi; Giroletti, M.; Graham, M. J.; Karambelkar, Viraj; Kimura, Shigeo S.; Kong, A. K. H.; Kool, Erik C.; Laher, Russ R.; Медведев, П. С.; Necker, Jannis; Nordin, J.; Perley, D.; Rigault, M.; Schulze, S.; Schweyer, T.; Singer, L. P.; Sollerman, J.; Strotjohann, N. L.; Sunyaev, R.; Santen, J. V.; Walters, Richard; Zhang, B. Theodore; Zimmerman, E.

doi:10.1103/physrevlett.128.221101

“…TDEs have been suggested as candidates for producing highenergy protons and neutrinos (Murase et al 2020b), which is also supported by recently reported neutrino events associated with TDEs (e.g., Reusch et al 2022;Stein et al 2021;van Velzen et al 2021). However, with a steep spectrum of highenergy protons, it would be difficult for TDE outflows to account for the observed PeV neutrinos (Wu et al 2022).…”

Section: Discussionsupporting

confidence: 56%

Quasi-perpendicular Shock Acceleration and Tidal Disruption Event Radio Flares

Xu

2022

ApJ

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Delayed radio flares of optical tidal disruption events (TDEs) indicate the existence of nonrelativistic outflows accompanying TDEs. The interaction of TDE outflows with the surrounding circumnuclear medium creates quasi-perpendicular shocks in the presence of toroidal magnetic fields. Because of the large shock obliquity and large outflow velocity, we find that the shock acceleration induced by TDE outflows generally leads to a steep particle energy spectrum, with the power-law index significantly larger than the “universal” index for a parallel shock. The measured synchrotron spectral indices of recently detected TDE radio flares are consistent with our theoretical expectation. It suggests that the particle acceleration at quasi-perpendicular shocks can be the general acceleration mechanism accounting for the delayed radio emission of TDEs.

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“…We speculate that these could arise from jets or winds from the inner accretion disk that suddenly become more powerful as the SMBH accretion rate rises rapidly near the termination of the envelope cooling −contraction phase. Shocks driven by such outflows into the surrounding wind/envelope material could in principle accelerate relativistic ions, generating a source of high-energy gamma-rays and neutrinos (Lunardini & Winter 2017;Senno et al 2017;Guépin et al 2018;Fang et al 2020;Murase et al 2020), perhaps explaining the significant observed delay between the high-energy neutrino detections from a growing sample of TDE and the optical light-curve maximum (van Velzen et al 2021b;Stein et al 2021;Reusch et al 2022).…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, several TDEs exhibit late-time radio flares, indicating mildly relativistic material ejected from the vicinity of the SMBH, but delayed from the optical peak by several months to years (e.g., Horesh et al 2021aHoresh et al , 2021bCendes et al 2022;Sfaradi et al 2022). A potentially related occurrence is the coincident detection of high-energy neutrinos from three optical TDEs by IceCube (van Velzen et al 2021b;Stein et al 2021;Reusch et al 2022), each of which also arrived several months after the optical peak. State transitions in the accretion flow offer one potential explanation for the delayed onset of jetted accretion activity (e.g., Tchekhovskoy et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Cooling Envelope Model for Tidal Disruption Events

Metzger

¹

2022

ApJL

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We present a toy model for the thermal optical/UV/X-ray emission from tidal disruption events (TDEs). Motivated by recent hydrodynamical simulations, we assume that the debris streams promptly and rapidly circularize (on the orbital period of the most tightly bound debris), generating a hot quasi-spherical pressure-supported envelope of radius R v ∼ 1014 cm (photosphere radius ∼1015 cm) surrounding the supermassive black hole (SMBH). As the envelope cools radiatively, it undergoes Kelvin–Helmholtz contraction R v ∝ t −1, its temperature rising T eff ∝ t 1/2 while its total luminosity remains roughly constant; the optical luminosity decays as ν L ν ∝ R v 2 T eff ∝ t − 3 / 2 . Despite this similarity to the mass fallback rate M ̇ fb ∝ t − 5 / 3 , envelope heating from fallback accretion is subdominant compared to the envelope cooling luminosity except near optical peak (where they are comparable). Envelope contraction can be delayed by energy injection from accretion from the inner envelope onto the SMBH in a regulated manner, leading to a late-time flattening of the optical/X-ray light curves, similar to those observed in some TDEs. Eventually, as the envelope contracts to near the circularization radius, the SMBH accretion rate rises to its maximum, in tandem with the decreasing optical luminosity. This cooling-induced (rather than circularization-induced) delay of up to several hundred days may account for the delayed onset of thermal X-rays, late-time radio flares, and high-energy neutrino generation, observed in some TDEs. We compare the model predictions to recent TDE light-curve correlation studies, finding both agreement and points of tension.

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“…Since the first detection of highenergy neutrinos of astrophysical origin by the IceCube Neutrino Observatory, the follow-up searches are ongoing to pinpoint the electromagnetic counterparts associated to the IceCube neutrino events (Abbasi et al 2021a;Garrappa et al 2019;Acciari et al 2021;Necker et al 2022;Stein et al 2022). A dozen of the neutrino events have been associated in likely coincidence with blazars, tidal disruption events, or superluminous SNe (Aartsen et al 2018a;Giommi et al 2020;Franckowiak et al 2020;Garrappa et al 2019;Krauß et al 2018;Kadler et al 2016;Stein et al 2021;Reusch et al 2022;Pitik et al 2022). As for LFBOTs, the IceCube Neutrino Observatory reported the detection of two track-like muon neutrino events in spatial coincidence with AT2018cow in the 3.5 days following the optical detection.…”

Section: Introductionmentioning

confidence: 99%

Neutrino Emission from Luminous Fast Blue Optical Transients

Guarini

¹

,

Tamborra

²

,

Margutti

³

2022

ApJ

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Mounting evidence suggests that luminous fast blue optical transients (LFBOTs) are powered by a compact object, launching an asymmetric and fast outflow responsible for the radiation observed in the ultraviolet, optical, infrared, radio, and X-ray bands. Proposed scenarios aiming to explain the electromagnetic emission include an inflated cocoon, surrounding a jet choked in the extended stellar envelope. Alternatively, the observed radiation may arise from the disk formed by the delayed merger of a black hole with a Wolf–Rayet star. We explore the neutrino production in these scenarios, i.e., internal shocks in a choked jet and interaction between the outflow and the circumstellar medium (CSM). If observed on axis, the choked jet provides the dominant contribution to the neutrino fluence. Intriguingly, the IceCube upper limit on the neutrino emission inferred from the closest LFBOT, AT2018cow, excludes a region of the parameter space otherwise allowed by electromagnetic observations. After correcting for the Eddington bias on the observation of cosmic neutrinos, we conclude that the emission from an on-axis choked jet and CSM interaction is compatible with the detection of two track-like neutrino events observed by the IceCube Neutrino Observatory in coincidence with AT2018cow, and otherwise considered to be of atmospheric origin. While the neutrino emission from LFBOTs does not constitute the bulk of the diffuse background of neutrinos observed by IceCube, the detection prospects of nearby LFBOTs with IceCube and the upcoming IceCube-Gen2 are encouraging. Follow-up neutrino searches will be crucial for unraveling the mechanism powering this emergent transient class.

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Candidate Tidal Disruption Event AT2019fdr Coincident with a High-Energy Neutrino

Cited by 70 publications

References 133 publications

Quasi-perpendicular Shock Acceleration and Tidal Disruption Event Radio Flares

Quasi-perpendicular Shock Acceleration and Tidal Disruption Event Radio Flares

Cooling Envelope Model for Tidal Disruption Events

Neutrino Emission from Luminous Fast Blue Optical Transients

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