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Monika Moscibrodzka

Astrophysicist enjoying numerical astrophysics, modeling fluid dynamics, imaging black hole shadows, chasing accelerated particles


 





Here I list four main research projects that I'm leading or I'm involved in. Astronomy/physics students who would like to work with me on any of the listed topics are welcome to contact me.

1. Hunting for Black Hole Shadows in the Centers of the Milky Way and M87 Galaxy

Both observationally and theoretically, the study of gas flows near black holes is on the verge of a breakthrough. Observationally, the Event Horizon Telescope will soon make for the first time resolved images of the black holes at event horizon scales in the centers of the Milky Way and the M87 galaxy. I am involved in all these efforts through the ERC Black Hole Camera collaboration.

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This is not a real picture of a black hole shadow. This is a theoretical prediction of apperance of the black hole event horizon in the center of the Milky Way at mm wavelength at which EHT operates. See one of my articles in Astronomy and Astrophysics for more details.

2. Constraining Physics of Accretion and Jets in Low Luminosity Active Galactic Nuclei

Recent improvements in theoretical modeling for the first time allow for realistic and detailed predictions of the observational signatures of accretion flows and jets near a black hole. High performance computations allow us now to follow the dynamics of plasma and magnetic fields in the vicinity of the black hole in great detail. However, coupling these simulations properly to observations via radiation remained a problem for a long time. The main source of uncertainty is the thermodynamics of radiating electrons. I have recently found a natural way to parametrize the electron thermodynamics which properly recovers the basic observational characteristics of black hole systems.



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Movie

Click on the figure above to follow the evolution of realistic model of accreting black hole as seen by observer on earth. The movie starts when the black hole is surrounded by a ring of magnetized plasma. Due to viscous forces caused by magnetic turbulence the plasma looses angular momentum and falls onto the black hole event horizon. In a later stage a relativistic jet is formed. The movie is a result of combing 3D general relativistic MHD simulations of fluid dynamics around Kerr black hole (with HARM-3D code) with general relativistic radiative transfer model. We will confront this and other models of accretion with various radio/millimeter VLBI and high energy (like in Near Infrared and X-ray bands) observations and estimate the properties of plasma and black hole spin in aforementioned astrophysical systems.

3. Covariant Polarized Radiative Transfer

To confront MHD accretion theory with astrophysical observations a good model of radiative transfer is required. I have developed and co-developed (with graduate students) a few various state-of-the-art codes for simulating radiative transfer through astrophysical plasma in strong gravitational field. My latest development is ipole - a semianalytic, covariant (i.e., independent of geometry of spacetime) general relativistic code for polarized radiative transport. My code is public and free to use, it will be available here. The code documentation is published in Monthly Notices of Royal Astronomical Society. How a magnetized accretion flow onto a black hole looks like in polarized light? The figure below shows one of the World most accurate images of that based on ipole calculation.

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The information about geometry of magnetic fields is in polarized component of radiation (Stokes Q, U, and V). Modeling the polarized electromagnetic counterparts of accreting black holes is the most promissing way to learn about magnetizm of compact objects. This study is crucial to find out, for example, how relativistic jets, that we do observe in many astrophysical systems, are launched and powered.

4. Radiation-driven Outflows from Active Galactic Nuclei

What is the role of supermassive black holes in shaping the galaxies and influence the evolution of the Universe ? There is a growing observational evidence that their role is significant. Numerical models of gas accretion in Active Galactic Nuclei (AGN) that cover a radial range between 0.1-200 pc may allow to link the galactic/cosmological simulations with small scale black hole accretion disk models within a few hundreds of Schwarschild radii. We study the dynamics of accretion flows and associated outflows in numerical simulations which example is shown below. See my article in Astrophysical Journal for more details.

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Click here to see the growth of thermal instability and development of outflows in gas accreting onto supermassive black hole in AGN. The accreting gas breaks into a two-phase medium because it is illuminated and photo-ionized by central source of high energy emission. In collaboration with partners from UNLV, we will examine the details of gas and light interations in the near future study.



















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