Quasi-periodic flares from star-accretion-disc collisions

Dai, Lixin; Fuerst, Steven V.; Blandford, R. D.

doi:10.1111/j.1365-2966.2009.16038.x

Cited by 22 publications

(1 citation statement)

References 61 publications

(64 reference statements)

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“…Usually the hotspot scenario is employed to model a localized brightness excess within an accretion flow. A hotspot could arise through magnetic turbulence in a magneto-hydrodynamic accretion flow (Balbus & Hawley 1991;Armitage & Reynolds 2003), vortices and flux tubes (Abramowicz et al 1992), magnetic flares (Poutanen & Fabian 1999;Życki 2002), interactions of stars with an accretion disk (Dai et al 2010), or magnetic reconnection (Yuan et al 2009). According to Eckart et al (2012) it is most likely that the X-ray flares of Sgr A* (see also Eckart et al 2002;Baganoff et al 2001).…”

Section: Setup Of the Modelsmentioning

confidence: 99%

Bright X-ray flares from Sgr A*

Karssen

Bursa

Eckart

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We address a question whether the observed light curves of X-ray flares originating deep in galactic cores can give us independent constraints on the mass of the central supermassive black hole. To this end we study four brightest flares that have been recorded from Sagittarius A*. They all exhibit an asymmetric shape consistent with a combination of two intrinsically separate peaks that occur at a certain time-delay with respect to each other, and are characterized by their mutual flux ratio and the profile of raising/declining parts. Such asymmetric shapes arise naturally in the scenario of a temporary flash from a source orbiting near a supermassive black hole, at radius of only ∼ 10-20 gravitational radii. An interplay of relativistic effects is responsible for the modulation of the observed light curves: Doppler boosting, gravitational redshift, light focusing, and light-travel time delays. We find the flare properties to be in agreement with the simulations (our ray-tracing code sim5lib). The inferred mass for each of the flares comes out in agreement with previous estimates based on orbits of stars; the latter have been observed at radii and over time-scales two orders of magnitude larger than those typical for the X-ray flares, so the two methods are genuinely different. We test the reliability of the method by applying it to another object, namely, the Seyfert I galaxy RE J1034+396.

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Section: Setup Of the Modelsmentioning

confidence: 99%

Bright X-ray flares from Sgr A*

Karssen

Bursa

Eckart

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Tidal disruption events and quasi‐periodic eruptions

et al. 2023

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Tidal disruption events (TDEs) occur when a star passes close to a massive black hole so that the tidal forces of the black hole exceed the binding energy of a star and cause it to be ripped apart. Part of the matter will fall onto the black hole, causing a strong increase in luminosity. Such events are often seen in the optical or the x-ray (or both) or even at other wavelengths such as in the radio, where the diversity of observed emission is still poorly understood. The XMM-Newton catalog of approximately a million x-ray detections covering 1283 2 degrees of sky contains a number of these events. Here I will show the diverse nature of a number of TDEs discovered in the catalog and discuss their relationship with quasi-periodic eruptions.

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