scholarly journals Simulating disc formation in tidal disruption events

2020 ◽  
Vol 495 (1) ◽  
pp. 1374-1391 ◽  
Author(s):  
Clément Bonnerot ◽  
Wenbin Lu
Keyword(s):  
Black Hole ◽  
Initial Conditions ◽  
Large Fraction ◽  
Compact Object ◽  
Intersection Point ◽  
Tidal Disruption ◽  
Bolometric Luminosity ◽  
Supermassive Black Hole ◽  
Distribution Features ◽  
Early Radiation

ABSTRACT A star coming too close to a supermassive black hole gets disrupted by the tidal force of the compact object in a tidal disruption event, or TDE. Following this encounter, the debris evolves into an elongated stream, half of which coming back to pericentre. Relativistic apsidal precession then leads to a self-crossing shock that initiates the formation of an accretion disc. We perform the first simulation of this process considering a parabolic encounter with a supermassive black hole, which has so far eluded investigations for computational reasons. This numerical issue is alleviated by using as initial conditions the outflow launched by the self-crossing shock according the local simulation of Lu & Bonnerot (2020). We find that the gas leaving the intersection point experiences numerous secondary shocks that result in the rapid formation of a thick and marginally bound disc. The mass distribution features two overdensities identified as spiral shocks that drive slow gas inflow along the mid-plane. Inward motion primarily takes place along the funnels of the newly formed torus, from which a fraction of the matter can get accreted. Further out, the gas moves outward forming an extended envelope completely surrounding the accretion flow. Secondary shocks heat the debris at a rate of a few times $10^{44} \, \rm erg\, s^{-1}$ with a large fraction likely participating to the bolometric luminosity. These results pave the way towards a complete understanding of the early radiation from TDEs that progressively becomes accessible from observations.

scholarly journals The ecology of the galactic centre: Nuclear stellar clusters and supermassive black holes

2019 ◽  
Vol 14 (S351) ◽  
pp. 80-83 ◽  
Author(s):  
Melvyn B. Davies ◽  
Abbas Askar ◽  
Ross P. Church
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Large Fraction ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Galactic Centre ◽  
Stellar Clusters ◽  
Stellar Cluster ◽  
Supermassive Black Hole ◽  
Multiple Clusters

AbstractSupermassive black holes are found in most galactic nuclei. A large fraction of these nuclei also contain a nuclear stellar cluster surrounding the black hole. Here we consider the idea that the nuclear stellar cluster formed first and that the supermassive black hole grew later. In particular we consider the merger of three stellar clusters to form a nuclear stellar cluster, where some of these clusters contain a single intermediate-mass black hole (IMBH). In the cases where multiple clusters contain IMBHs, we discuss whether the black holes are likely to merge and whether such mergers are likely to result in the ejection of the merged black hole from the nuclear stellar cluster. In some cases, no supermassive black hole will form as any merger product is not retained. This is a natural pathway to explain those galactic nuclei that contain a nuclear stellar cluster but apparently lack a supermassive black hole; M33 being a nearby example. Alternatively, if an IMBH merger product is retained within the nuclear stellar cluster, it may subsequently grow, e.g. via the tidal disruption of stars, to form a supermassive black hole.

scholarly journals Tidal disruption events on to stellar black holes in triples

2019 ◽  
Vol 489 (1) ◽  
pp. 727-737 ◽  
Author(s):  
Giacomo Fragione ◽  
Nathan W C Leigh ◽  
Rosalba Perna ◽  
Bence Kocsis
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Force ◽  
Main Sequence ◽  
Initial Conditions ◽  
Main Sequence Stars ◽  
Tidal Disruption ◽  
Mean Velocity ◽  
Massive Black Holes ◽  
The Mean

ABSTRACT Stars passing too close to a black hole can produce tidal disruption events (TDEs), when the tidal force across the star exceeds the gravitational force that binds it. TDEs have usually been discussed in relation to massive black holes that reside in the centres of galaxies or lurk in star clusters. We investigate the possibility that triple stars hosting a stellar black hole (SBH) may be sources of TDEs. We start from a triple system made up of three main-sequence stars and model the supernova (SN) kick event that led to the production of an inner binary comprised of an SBH. We evolve these triples with a high-precision N-body code and study their TDEs as a result of Kozai–Lidov oscillations. We explore a variety of distributions of natal kicks imparted during the SN event, various maximum initial separations for the triples, and different distributions of eccentricities. We show that the main parameter that governs the properties of the SBH–MS binaries that produce a TDE in triples is the mean velocity of the natal kick distribution. Smaller σ’s lead to larger inner and outer semimajor axes of the systems that undergo a TDE, smaller SBH masses, and longer time-scales. We find that the fraction of systems that produce a TDE is roughly independent of the initial conditions, while estimate a TDE rate of $2.1\times 10^{-4}{\!-\!}4.7 \, \mathrm{yr}^{-1}$, depending on the prescriptions for the SBH natal kicks. This rate is almost comparable to the expected TDE rate for massive black holes.

scholarly journals X-ray flares from the stellar tidal disruption by a candidate supermassive black hole binary

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xinwen Shu ◽  
Wenjie Zhang ◽  
Shuo Li ◽  
Ning Jiang ◽  
Liming Dou ◽  
...  
Keyword(s):  
Black Hole ◽  
X Rays ◽  
Tidal Disruption ◽  
Massive Black Hole ◽  
Ultraviolet Emission ◽  
X Ray ◽  
Black Hole Binaries ◽  
Supermassive Black Hole ◽  
Black Hole Binary

AbstractOptical transient surveys have led to the discovery of dozens of stellar tidal disruption events (TDEs) by massive black hole in the centers of galaxies. Despite extensive searches, X-ray follow-up observations have produced no or only weak X-ray detections in most of them. Here we report the discovery of delayed X-ray brightening around 140 days after the optical outburst in the TDE OGLE16aaa, followed by several flux dips during the decay phase. These properties are unusual for standard TDEs and could be explained by the presence of supermassive black hole binary or patchy obscuration. In either scenario, the X-rays can be produced promptly after the disruption but are blocked in the early phase, possibly by a radiation-dominated ejecta which leads to the bulk of optical and ultraviolet emission. Our findings imply that the reprocessing is important in the TDE early evolution, and X-ray observations are promising in revealing supermassive black hole binaries.

scholarly journals Tidal disruption as a probe for supermassive black hole binaries

2014 ◽  
Vol 10 (S312) ◽  
pp. 43-47
Author(s):  
Shuo Li ◽  
Fukun Liu ◽  
Peter Berczik ◽  
Rainer Spurzem
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Galactic Center ◽  
Galaxy Mergers ◽  
Tidal Disruption ◽  
Black Hole Binaries ◽  
Supermassive Black Hole ◽  
Before And After ◽  
Many Core ◽  
Disruption Event

AbstractSupermassive black hole binaries (SMBHBs) are the products of frequent galaxy mergers. It is very hard to be detected in quiescent galaxy. By using one million particle direct N-body simulations on special many-core hardware (GPU cluster), we study the dynamical co-evolution of SMBHB and its surrounding stars, specially focusing on the evolution of stellar tidal disruption event (TDE) rates before and after the coalescence of the SMBHB. We find a boosted TDE rate during the merger of the galaxies. After the coalescence of two supermassive black holes (SMBHs), the post-merger SMBH can get a kick velocity due to the anisotropic GW radiations. Our results about the recoiling SMBH, which oscillates around galactic center, show that most of TDEs are contributed by unbound stars when the SMBH passing through galactic center. In addition, the TDE light curve in SMBHB system is significantly different from the curve for single SMBH, which can be used to identify the SMBHB.

scholarly journals Tidal disruption events from supermassive black hole binaries

2016 ◽  
Vol 465 (4) ◽  
pp. 3840-3864 ◽  
Author(s):  
Eric R. Coughlin ◽  
Philip J. Armitage ◽  
Chris Nixon ◽  
Mitchell C. Begelman
Keyword(s):  
Black Hole ◽  
Tidal Disruption ◽  
Black Hole Binaries ◽  
Supermassive Black Hole

scholarly journals Ultraviolet Detection of the Tidal Disruption of a Star by a Supermassive Black Hole

2006 ◽  
Vol 653 (1) ◽  
pp. L25-L28 ◽  
Author(s):  
S. Gezari ◽  
D. C. Martin ◽  
B. Milliard ◽  
S. Basa ◽  
J. P. Halpern ◽  
...  
Keyword(s):  
Black Hole ◽  
Tidal Disruption ◽  
Ultraviolet Detection ◽  
Supermassive Black Hole
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