Relative depolarization of the black hole photon ring in GRMHD models of Sgr A* and M87* [HEAP]

http://arxiv.org/abs/2103.06292


Using general relativistic magnetohydrodynamic simulations of accreting black holes, we show that a suitable subtraction of the linear polarization per pixel from total intensity images can enhance the photon ring features. We find that the photon ring is typically a factor of $\simeq 2$ less polarized than the rest of the image. This is due to a combination of plasma and general relativistic effects, as well as magnetic turbulence. When there are no other persistently depolarized image features, adding the subtracted residuals over time results in a sharp image of the photon ring. We show that the method works well for sample, viable GRMHD models of Sgr A* and M87*, where measurements of the photon ring properties would provide new measurements of black hole mass and spin, and potentially allow for tests of the “no-hair” theorem of general relativity.

Read this paper on arXiv…

A. Jiménez-Rosales, J. Dexter, S. Ressler, et. al.
Fri, 12 Mar 21
23/59

Comments: 13 pages, 12 figures, accepted for publication in MNRAS