scholarly journals MEASURING MASS ACCRETION RATE ONTO THE SUPERMASSIVE BLACK HOLE IN M87 USING FARADAY ROTATION MEASURE WITH THE SUBMILLIMETER ARRAY

2014 ◽  
Vol 783 (2) ◽  
pp. L33 ◽  
Author(s):  
C. Y. Kuo ◽  
K. Asada ◽  
R. Rao ◽  
M. Nakamura ◽  
J. C. Algaba ◽  
...  
Keyword(s):  
Black Hole ◽  
Faraday Rotation ◽  
Accretion Rate ◽  
Mass Accretion Rate ◽  
Supermassive Black Hole ◽  
Rotation Measure

scholarly journals Observational signatures of magnetic field structure in relativistic AGN jets

2019 ◽  
Vol 622 ◽  
pp. A122 ◽  
Author(s):  
Christopher Prior ◽  
Konstantinos N. Gourgouliatos
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Magnetic Fields ◽  
Radio Emission ◽  
Faraday Rotation ◽  
Large Scale ◽  
Field Structure ◽  
Synchrotron Emission ◽  
Supermassive Black Hole ◽  
Rotation Measure

Context. Active galactic nuclei (AGN) launch highly energetic jets sometimes outshining their host galaxy. These jets are collimated outflows that have been accelerated near a supermassive black hole located at the centre of the galaxy. Their, virtually indispensable, energy reservoir is either due to gravitational energy released from accretion or due to the extraction of kinetic energy from the rotating supermassive black hole itself. In order to channel part of this energy to the jet, though, the presence of magnetic fields is necessary. The extent to which these magnetic fields survive in the jet further from the launching region is under debate. Nevertheless, observations of polarised emission and Faraday rotation measure confirm the existence of large scale magnetic fields in jets. Aims. Various models describing the origin of the magnetic fields in AGN jets lead to different predictions about the large scale structure of the magnetic field. In this paper we study the observational signatures of different magnetic field configurations that may exist in AGN jets in order to asses what kind of information regarding the field structure can be obtained from radio emission, and what would be missed. Methods. We explore three families of magnetic field configurations. First, a force-free helical magnetic field corresponding to a dynamically relaxed field in the rest frame of the jet. Second, a magnetic field with a co-axial cable structure arising from the Biermann-battery effect at the accretion disk. Third, a braided magnetic field that could be generated by turbulent motion at the accretion disk. We evaluate the intensity of synchrotron emission, the intrinsic polarization profile and the Faraday rotation measure arising from these fields. We assume that the jet consists of a relativistic spine where the radiation originates from and a sheath containing thermalised electrons responsible for the Faraday screening. We evaluate these values for a range of viewing angles and Lorentz factors. We account for Gaussian beaming that smooths the observed profile. Results. Radio emission distributions from the jets with dominant large-scale helical fields show asymmetry across their width. The Faraday rotation asymmetry is the same for fields with opposing chirality (handedness). For jets which are tilted towards the observer the synchrotron emission and fractional polarization can distinguish the field’s chirality. When viewed either side-on or at a Blazar type angle only the fractional polarization can make this distinction. Further this distinction can only be made if the direction of the jet propagation velocity is known, along with the location of the jet’s origin. The complex structure of the braided field is found not to be observable due to a combination of line of sight integration and limited resolution of observation. This raises the possibility that, even if asymmetric radio emission signatures are present, the true structure of the field may still be obscure.

scholarly journals Constraints on the Mass Accretion Rate onto the Supermassive Black Hole of Cygnus A Using the Submillimeter Array

2021 ◽  
Vol 911 (1) ◽  
pp. 35
Author(s):  
Wen-Ping Lo ◽  
Keiichi Asada ◽  
Satoki Matsushita ◽  
Masanori Nakamura ◽  
Hung-Yi Pu ◽  
...  
Keyword(s):  
Black Hole ◽  
Accretion Rate ◽  
Mass Accretion Rate ◽  
Supermassive Black Hole ◽  
Cygnus A

scholarly journals H2O maser emission from the Seyfert 2 galaxy IC 2560: evidence for a super-massive black hole and a probe for mass-accretion rate

2002 ◽  
Vol 206 ◽  
pp. 400-403
Author(s):  
Yuko Ishihara ◽  
Naomasa Nakai ◽  
Naoko Iyomoto ◽  
Kazuo Makishima ◽  
Phil Diamond ◽  
...  
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Accretion Rate ◽  
Rotating Disk ◽  
Massive Black Hole ◽  
Central Mass ◽  
Maser Emission ◽  
Mass Accretion Rate ◽  
Systemic Velocity ◽  
Velocity Drift

Our observations of H2O masers have detected some high-velocity features and a secular velocity drift of the systemic features in the Seyfert 2 Galaxy IC 2560. The high-velocity features were blue- and red-shifted from the systemic velocity of 220-420 km s−1 and 210-350 km s−1, respectively. The velocity of the systemic features drifted at a secular rate of 2.62 km s−1 yr−1. Assuming the existence of a compact rotating disk as in NGC 4258, IC 2560 possesses a nuclear disk with inner and outer radii of 0.07 pc and 0.26 pc, respectively, and a confined mass of 2.8 × 106M⊙ at the center, making the central density > 2.1 × 109M⊙ pc−3. Such a dense object cannot be a cluster of stars, and this strongly suggests that the central mass is a super-massive black hole. Since the 2-10 keV luminosity of IC 2560 is 1 × 1041 erg s−1, the mass accretion rate of the suggested black hole must be 2 × 10−5M⊙ yr−1.

scholarly journals Matter accretion onto a conformal gravity black hole

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
G. Abbas ◽  
A. Ditta
Keyword(s):  
Black Hole ◽  
Equations Of State ◽  
Accretion Rate ◽  
Black Hole Mass ◽  
Conformal Gravity ◽  
De Sitter ◽  
Schwarzschild Black Hole ◽  
Mass Rate ◽  
Mass Accretion Rate ◽  
The Impact

AbstractThe accretion of test fluids flowing onto a black hole is investigated. Particularly, by adopting a dynamical Hamiltonian approach, we are capable to find the critical points for various cases of black hole in conformal gravity. In these cases, we have analyzed the general solutions of accretion employing the isothermal equations of state. The steady state and spherically symmetric accretion of different test fluids onto the conformal gravity black hole has been considered. Further, we have classified these flows in the context of equations of state and the cases of conformal gravity black hole. The new behavior of polytropic fluid accretion is also discussed in all three cases of black hole. Black hole mass accretion rate is the most important part of this research in which we have investigated that the Schwarzschild black hole produce a typical signature than the conformal gravity black hole and Schwarzschild–de Sitter black hole. The critical fluid flow and the mass accretion rate have been presented graphically by the impact parameters $$\beta $$ β , $$\gamma $$ γ , k and these parameters have great significance. Additionally, the maximum mass rate of accretion fall near the universal and Killing horizons and minimum rate of accretion occurs in between these regions. Finally, the results are compared with the different cases of black hole available in the literature.

scholarly journals Deep Horizon: A machine learning network that recovers accreting black hole parameters

2020 ◽  
Vol 636 ◽  
pp. A94 ◽  
Author(s):  
Jeffrey van der Gucht ◽  
Jordy Davelaar ◽  
Luc Hendriks ◽  
Oliver Porth ◽  
Hector Olivares ◽  
...  
Keyword(s):  
Neural Networks ◽  
Black Hole ◽  
Event Horizon ◽  
Deep Neural Networks ◽  
Accretion Rate ◽  
Position Angle ◽  
Physical Parameters ◽  
Mass Accretion Rate ◽  
Parameter Estimations ◽  
Deep Horizon

Context. The Event Horizon Telescope recently observed the first shadow of a black hole. Images like this can potentially be used to test or constrain theories of gravity and deepen the understanding in plasma physics at event horizon scales, which requires accurate parameter estimations. Aims. In this work, we present Deep Horizon, two convolutional deep neural networks that recover the physical parameters from images of black hole shadows. We investigate the effects of a limited telescope resolution and observations at higher frequencies. Methods. We trained two convolutional deep neural networks on a large image library of simulated mock data. The first network is a Bayesian deep neural regression network and is used to recover the viewing angle i, and position angle, mass accretion rate Ṁ, electron heating prescription Rhigh and the black hole mass MBH. The second network is a classification network that recovers the black hole spin a. Results. We find that with the current resolution of the Event Horizon Telescope, it is only possible to accurately recover a limited number of parameters of a static image, namely the mass and mass accretion rate. Since potential future space-based observing missions will operate at frequencies above 230 GHz, we also investigated the applicability of our network at a frequency of 690 GHz. The expected resolution of space-based missions is higher than the current resolution of the Event Horizon Telescope, and we show that Deep Horizon can accurately recover the parameters of simulated observations with a comparable resolution to such missions.

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