Bayesian TECHNIQUES for COMPARING TIME-DEPENDENT GRMHD SIMULATIONS to VARIABLE EVENT HORIZON TELESCOPE OBSERVATIONS

Junhan Kim, Daniel P. Marrone, Chi Kwan Chan, Lia Medeiros, Feryal Özel, Dimitrios Psaltis

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The Event Horizon Telescope (EHT) is a millimeter-wavelength, very-long-baseline interferometry (VLBI) experiment that is capable of observing black holes with horizon-scale resolution. Early observations have revealed variable horizon-scale emission in the Galactic Center black hole, Sagittarius A∗ (Sgr A∗). Comparing such observations to time-dependent general relativistic magnetohydrodynamic (GRMHD) simulations requires statistical tools that explicitly consider the variability in both the data and the models. We develop here a Bayesian method to compare time-resolved simulation images to variable VLBI data, in order to infer model parameters and perform model comparisons. We use mock EHT data based on GRMHD simulations to explore the robustness of this Bayesian method and contrast it to approaches that do not consider the effects of variability. We find that time-independent models lead to offset values of the inferred parameters with artificially reduced uncertainties. Moreover, neglecting the variability in the data and the models often leads to erroneous model selections. We finally apply our method to the early EHT data on Sgr A∗.

Original languageEnglish (US)
Article number156
JournalAstrophysical Journal
Volume832
Issue number2
DOIs
StatePublished - Dec 1 2016

Keywords

  • Galaxy: center
  • black hole physics
  • methods: statistical
  • submillimeter: general
  • techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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