The Accretion Flow in M87 is Really MAD

Yuan, Feng; Wang, Haiyang; Yang, Hai Tao

doi:10.3847/1538-4357/ac4714

Cited by 26 publications

(20 citation statements)

References 50 publications

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“…The observationally measured ejection velocity of 0.4, 0.5, and 0.2 of the speed of light for the ejected plasmoids in Sgr A * , M81, and M87 is also quantitatively similar to what we have obtained in the case of MAD, as shown in Figure 9, which is about 0.3 of the speed of light. The "MAD" nature of the accretion flow in M81 and M87 is consistent with most recent studies (Event Horizon Telescope Collaboration et al 2021;Shi et al 2021;Yuan et al 2022).…”

Section: Periodic Flares and The Hot Spot In Sgr A * And Other Black ...supporting

confidence: 90%

Formation of Episodic Jets and Associated Flares from Black Hole Accretion Systems

Čemeljić

Yang

Yuan

et al. 2022

ApJ

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Episodic ejections of blobs (episodic jets) are widely observed in black hole sources and usually associated with flares. In this paper, by performing and analyzing three-dimensional general relativity magnetohydrodynamical numerical simulations of accretion flows, we investigate their physical mechanisms. We find that magnetic reconnection occurs in the accretion flow, likely due to the turbulent motion and differential rotation of the accretion flow, resulting in flares and formation of flux ropes. Flux ropes formed inside of 10–15 gravitational radii are found to mainly stay within the accretion flow, while flux ropes formed beyond this radius are ejected outward by magnetic forces and form the episodic jets. These results confirm the basic scenario proposed in Yuan et al. Moreover, our simulations find that the predicted velocity of the ejected blobs is in good consistency with observations of Sgr A*, M81, and M87. All of the processes were found to occur quasiperiodically, with the period being the orbital time at the radius where the flux rope is formed. The predicted period of the flares and ejections is consistent with those found from the light curves or image of Sgr A*, M87, and PKS 1510–089. The possible applications to protostellar accretion systems are discussed.

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Section: Periodic Flares and The Hot Spot In Sgr A * And Other Black ...supporting

confidence: 90%

Formation of Episodic Jets and Associated Flares from Black Hole Accretion Systems

Čemeljić

Yang

Yuan

et al. 2022

ApJ

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show abstract

“…The observationally measured ejection velocity of 0.4, 0.5, and 0.2 of the speed of light for the ejected plasmoids in Sgr A*, M81 and M87 is also quantitatively similar to what we have obtained in the case of MAD, as shown in Figure 9, which is about 0.3 of the speed of light. The "MAD" nature of the accretion flow in M81 and M87 is consistent with most recent studies (Shi et al 2021;Event Horizon Telescope Collaboration et al 2021;Yuan et al 2022).…”

Section: Ejected Blobs In Sgr A* M81 and M87: Origin Velocity And The...supporting

confidence: 89%

Formation of episodic jets and associated flares from black hole accretion systems

Cemeljic,

Yang,

Yuan

et al. 2022

Preprint

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Episodic ejections of blobs (episodic jets) are widely observed in black hole sources and usually associated with flares. In this paper, by performing and analyzing three dimensional general relativity magnetohydrodynamical numerical simulations of accretion flows, we investigate their physical mechanisms. We find that magnetic reconnection occurs in the accretion flow, likely due to the turbulent motion and differential rotation of the accretion flow, resulting in flares and formation of flux ropes. Flux ropes formed inside of 10-15 gravitational radii are found to mainly stay within the accretion flow, while flux ropes formed beyond this radius are ejected outward by magnetic forces and form the episodic jets. These results confirm the basic scenario proposed in Yuan et al. (2009). Moreover, our simulations find that the predicted velocity of the ejected blobs is in good consistency with observations of Sgr A*, M81, and M87. The whole processes are found to occur quasi-periodically, with the period being the orbital time at the radius where the flux rope is formed. The predicted period of flares and ejections is consistent with those found from the light curves or image of Sgr A*, M87, and PKS 1510-089. The possible applications to protostellar accretion systems are discussed.

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“…The estimated magnetic field for M87 * appears to be 1 − 30 Gauss, and the observed polarization map possibly resulted due to ordered radial and/or vertical magnetic fields present in the emission region. Recently, simulation studies of magnetically arrested disk (MAD; Igumenshchev et al 2003;Narayan et al 2003) successfully reproduced the similar polarimetric signatures (Palumbo et al 2020;Narayan et al 2021;Yuan et al 2022), which eventually indicate that the magnetic fields are dynamically important in the near-horizon region. Also, it is worth mentioning that the structure of seed magnetic fields plays an important role in governing the accretion-ejection mechanism around black hole.…”

mentioning

confidence: 80%

Study of general relativistic magnetohydrodynamic accretion flow around black holes

Mitra¹,

Maity²,

Dihingia³

et al. 2022

Preprint

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We present a novel approach to study the global structure of steady, axisymmetric, advective, geometrically thin, magnetohydrodynamic (MHD) accretion flow around black holes in full general relativity (GR). Considering ideal MHD conditions and relativistic equation of state (REoS), we solve the governing equations to obtain all possible smooth global accretion solutions. We examine the dynamical and thermodynamical properties of accreting matter in terms of the flow parameters, namely energy (E), angular momentum (L), and local magnetic fields. For a thin GRMHD flow, we observe that toroidal component (b φ ) of the magnetic fields generally dominates over radial component (b r ) at the disk equatorial plane. This evidently suggests that toroidal magnetic field indeed plays important role in regulating the disk dynamics. We further notice that the disk remains mostly gas pressure (p gas ) dominated (β = p gas /p mag > 1, p mag refers magnetic pressure) except at the near horizon region, where magnetic fields become dynamically important (β ∼ 1). We observe that Maxwell stress is developed that eventually yields angular momentum transport inside the disk. Towards this, we calculate the viscosity parameter (α) that appears to be radially varying. In addition, we examine the underlying scaling relation between α and β, which clearly distinguishes two domains coexisted along the radial extent of the disk. Finally, we discuss the utility of the present formalism in the realm of GRMHD simulation studies.

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The Accretion Flow in M87 is Really MAD

Cited by 26 publications

References 50 publications

Formation of Episodic Jets and Associated Flares from Black Hole Accretion Systems

Formation of Episodic Jets and Associated Flares from Black Hole Accretion Systems

Formation of episodic jets and associated flares from black hole accretion systems

Study of general relativistic magnetohydrodynamic accretion flow around black holes

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