Scary Barbie: An Extremely Energetic, Long-duration Tidal Disruption Event Candidate without a Detected Host Galaxy at z = 0.995

Subrayan, B. M.; Milisavljevic, Dan; Chornock, R.; Margutti, R.; Alexander, K. D.; Ramakrishnan, Vandana; Duffell, Paul C.; A., Dickinson, Danielle; Lee, Kyoung-Soo; Giannios, Dimitrios; Lentner, Geoffery; Linvill, M.; Garretson, Braden; Graham, M. J.; Stern, Daniel; Brethauer, Daniel; Duong, Tien Q.; Jacobson-Galán, W. V.; Natalie, LeBaron,; Matthews, D. J.; Sears, Huei; Venkatraman, Padma

doi:10.3847/2041-8213/accf1a

“…For example, the ∼decades-long X-ray outburst from the galaxy GSN 069, which was recently found to exhibit quasiperiodic eruptions (Miniutti et al 2019(Miniutti et al , 2023a(Miniutti et al , 2023b, was argued to be due to the disruption of a massive star (Sheng et al 2021). Similar claims in the context of other putative TDEs have been made by Lin et al (2017), Yan & Xie (2018), Cao et al (2023), and Subrayan et al (2023). In Lin et al (2017) in particular, the authors note that the disruption of a 10 M e star can explain a long-duration X-ray flare lasting over ∼11 yr.…”

Section: Long-duration Tdes From the Disruption Of Massive Starsmentioning

confidence: 73%

The Peak of the Fallback Rate from Tidal Disruption Events: Dependence on Stellar Type

Bandopadhyay,

Fancher,

Athian

et al. 2024

ApJL

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A star completely destroyed in a tidal disruption event (TDE) ignites a luminous flare that is powered by the fallback of tidally stripped debris to a supermassive black hole (SMBH) of mass M •. We analyze two estimates for the peak fallback rate in a TDE, one being the “frozen-in” model, which predicts a strong dependence of the time to peak fallback rate, t peak, on both stellar mass and age, with 15 days ≲ t peak ≲ 10 yr for main sequence stars with masses 0.2 ≤ M ⋆/M ⊙ ≤ 5 and M • = 106 M ⊙. The second estimate, which postulates that the star is completely destroyed when tides dominate the maximum stellar self-gravity, predicts that t peak is very weakly dependent on stellar type, with t peak = 23.2 ± 4.0 days M • / 10 6 M ⊙ 1 / 2 for 0.2 ≤ M ⋆/M ⊙ ≤ 5, while t peak = 29.8 ± 3.6 days M • / 10 6 M ⊙ 1 / 2 for a Kroupa initial mass function truncated at 1.5M ⊙. This second estimate also agrees closely with hydrodynamical simulations, while the frozen-in model is discrepant by orders of magnitude. We conclude that (1) the time to peak luminosity in complete TDEs is almost exclusively determined by SMBH mass, and (2) massive-star TDEs power the largest accretion luminosities. Consequently, (a) decades-long extra-galactic outbursts cannot be powered by complete TDEs, including massive-star disruptions, and (b) the most highly super-Eddington TDEs are powered by the complete disruption of massive stars, which—if responsible for producing jetted TDEs—would explain the rarity of jetted TDEs and their preference for young and star-forming host galaxies.

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Demographics of tidal disruption events with L-Galaxies

Polkas,

Bonoli,

Bortolas

et al. 2024

A&A

1

0

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Stars can be ripped apart by tidal forces in the vicinity of a massive black hole (MBH), causing luminous flares known as tidal disruption events (TDEs). These events could be contributing to the mass growth of intermediate-mass MBHs. New samples from transient surveys can provide useful information on this unexplored growth channel. This work aims to study the demographics of TDEs by modeling the coevolution of MBHs and their galactic environments in a cosmological framework. We use the semianalytic galaxy formation model L-Galaxies BH, which follows the evolution of galaxies as well as of MBHs, including multiple scenarios for MBH seeds and growth, spin evolution, and binary MBH dynamics. We associated time-dependent TDE rates with each MBH depending on the stellar environment, following the solutions to the 1D Fokker Planck equation solved with PHASEFLOW. Our model produces volumetric rates that are in agreement with the latest optical and previous X-ray samples. This agreement requires a high occupation fraction of nuclear star clusters with MBHs since these star reservoirs host the majority of TDEs at all mass regimes. We predict that TDE rates are an increasing function of MBH mass up to ∼105.5 M⊙, beyond which the distribution flattens and eventually drops for > 107 M⊙. In general, volumetric rates are predicted to be redshift independent at z < 1. We discuss how the spin distribution of MBHs around the event horizon suppression can be constrained via TDE rates and the average contribution of TDEs to the MBH growth. In our work, the majority of low-mass galaxies host nuclear star clusters that have their loss-cone depleted by z = 0, explaining why TDEs are rare in these systems. This highlights how essential time-dependent TDE rates are for any model to be in good agreement with observations at all mass regimes.

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Candidate young stellar objects in the S-cluster: Kinematic analysis of a subpopulation of the low-mass G objects close to Sgr A*

Peißker,

Zajaček,

Melamed

et al. 2024

A&A

1

0

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Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole Sgr A* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H − K and K − L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and mid-infrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of Sgr A* are much shorter (≪2 yr) than the epochs covered by the observations (≈15 yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20°, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of Sgr A*. Alternatively, the gravitational influence of Sgr A* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement.

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Scary Barbie: An Extremely Energetic, Long-duration Tidal Disruption Event Candidate without a Detected Host Galaxy at z = 0.995

Cited by 7 publications

References 124 publications

The Peak of the Fallback Rate from Tidal Disruption Events: Dependence on Stellar Type

The Peak of the Fallback Rate from Tidal Disruption Events: Dependence on Stellar Type

Demographics of tidal disruption events with L-Galaxies

Candidate young stellar objects in the S-cluster: Kinematic analysis of a subpopulation of the low-mass G objects close to Sgr A*

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