TY - JOUR
T1 - IPOLE - semi-analytic scheme for relativistic polarized radiative transport
AU - Mościbrodzka, M.
AU - Gammie, C. F.
N1 - Funding Information:
Monika Moscibrodzka acknowledges support from the European Research Council Synergy Grant ‘Black Hole Cam-Imaging the Event Horizon of Black Holes’ (Grant 610058). Charles F. Gam-mie acknowledges support from National Science Foundation grant AST-1333612 and AST-1716327, a Romano Professorial Scholarship, and the hospitality of the Flatiron Institute’s Center for Computational Astrophysics where some of this work was completed. The authors thank J. Dexter for his extensive help and guidance. The authors also thank B. Ryan, G. Janett, and the referee for their comments.
Publisher Copyright:
© 2017 The Author(s).
PY - 2018/3/21
Y1 - 2018/3/21
N2 - We describe IPOLE, a new public ray-tracing code for covariant, polarized radiative transport. The code extends the IBOTHROS scheme for covariant, unpolarized transport using two representations of the polarized radiation field: In the coordinate frame, it parallel transports the coherency tensor; in the frame of the plasma it evolves the Stokes parameters under emission, absorption, and Faraday conversion. The transport step is implemented to be as spacetime- and coordinate- independent as possible. The emission, absorption, and Faraday conversion step is implemented using an analytic solution to the polarized transport equation with constant coefficients. As a result, IPOLE is stable, efficient, and produces a physically reasonable solution even for a step with high optical depth and Faraday depth. We show that the code matches analytic results in flat space, and that it produces results that converge to those produced by Dexter's GRTRANS polarized transport code on a complicated model problem. We expect IPOLE will mainly find applications in modelling Event Horizon Telescope sources, but it may also be useful in other relativistic transport problems such as modelling for the IXPE mission.
AB - We describe IPOLE, a new public ray-tracing code for covariant, polarized radiative transport. The code extends the IBOTHROS scheme for covariant, unpolarized transport using two representations of the polarized radiation field: In the coordinate frame, it parallel transports the coherency tensor; in the frame of the plasma it evolves the Stokes parameters under emission, absorption, and Faraday conversion. The transport step is implemented to be as spacetime- and coordinate- independent as possible. The emission, absorption, and Faraday conversion step is implemented using an analytic solution to the polarized transport equation with constant coefficients. As a result, IPOLE is stable, efficient, and produces a physically reasonable solution even for a step with high optical depth and Faraday depth. We show that the code matches analytic results in flat space, and that it produces results that converge to those produced by Dexter's GRTRANS polarized transport code on a complicated model problem. We expect IPOLE will mainly find applications in modelling Event Horizon Telescope sources, but it may also be useful in other relativistic transport problems such as modelling for the IXPE mission.
KW - Black hole physics
KW - MHD
KW - Polarization
KW - Radiative transfer
KW - Relativistic processes
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U2 - 10.1093/mnras/stx3162
DO - 10.1093/mnras/stx3162
M3 - Article
AN - SCOPUS:85041328589
VL - 475
SP - 43
EP - 54
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
M1 - stx3162
ER -