Abstract
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 feature. We find that the photon ring is typically a factor of ≃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.
Original language | English (US) |
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Pages (from-to) | 4563-4575 |
Number of pages | 13 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 503 |
Issue number | 3 |
DOIs | |
State | Published - May 1 2021 |
Keywords
- Accretion
- Accretion discs
- Black hole physics
- MHD
- Polarization
- Radiative transfer
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science