Thumbnail
Access Restriction
Open

Author Gold, Roman ♦ McKinney, Jonathan C. ♦ Johnson, Michael D. ♦ Doeleman, Sheperd S.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ACCRETION DISKS ♦ BLACK HOLES ♦ COMPARATIVE EVALUATIONS ♦ ELECTRON TEMPERATURE ♦ EMISSION ♦ FLOW MODELS ♦ GALAXIES ♦ GHZ RANGE ♦ LIMITING VALUES ♦ MAGNETIC FIELDS ♦ MAGNETOHYDRODYNAMICS ♦ MASS ♦ POLARIZATION ♦ RADIANT HEAT TRANSFER ♦ RELATIVISTIC RANGE ♦ SIMULATION ♦ TELESCOPES ♦ THREE-DIMENSIONAL CALCULATIONS ♦ TIME DEPENDENCE
Abstract Magnetic fields are believed to drive accretion and relativistic jets in black hole accretion systems, but the magnetic field structure that controls these phenomena remains uncertain. We perform general relativistic (GR) polarized radiative transfer of time-dependent three-dimensional GR magnetohydrodynamical simulations to model thermal synchrotron emission from the Galactic Center source Sagittarius A* (Sgr A*). We compare our results to new polarimetry measurements by the Event Horizon Telescope (EHT) and show how polarization in the visibility (Fourier) domain distinguishes and constrains accretion flow models with different magnetic field structures. These include models with small-scale fields in disks driven by the magnetorotational instability as well as models with large-scale ordered fields in magnetically arrested disks. We also consider different electron temperature and jet mass-loading prescriptions that control the brightness of the disk, funnel-wall jet, and Blandford–Znajek-driven funnel jet. Our comparisons between the simulations and observations favor models with ordered magnetic fields near the black hole event horizon in Sgr A*, though both disk- and jet-dominated emission can satisfactorily explain most of the current EHT data. We also discuss how the black hole shadow can be filled-in by jet emission or mimicked by the absence of funnel jet emission. We show that stronger model constraints should be possible with upcoming circular polarization and higher frequency (349 GHz) measurements.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-03-10
Publisher Place United States
Journal Astrophysical Journal
Volume Number 837
Issue Number 2


Open content in new tab

   Open content in new tab