Constraints on Black Hole Jet Models Used As Diagnostic Tools of Event Horizon Telescope Observations of M87

Abstract

Jet models of Event Horizon Telescope (EHT) data should also conform to the observed jet profiles just downstream. This study evaluates conformance of models of black hole jets to images of the innermost jet of M87. This is a basic test that should be passed before using them to perform a physical interpretation of EHT data. Recent 86 GHz Very Long Baseline Interferometry observations of M87 have revealed the morphology and size of the jet near its source (< 65 M, or 0.06 lt-yrs after correcting for line of sight to the jet, where M is the black hole mass in geometrized units) for the first time. Current transverse resolution indicates that this region is dominated by flux emanating from the edge of the jet. The observed inner jet profiles are compared to all existing published synthetic radio images constructed from "state of the art" 3-D numerical simulations of the black hole accretion system in M87. Despite efforts to produce the characteristic wide, edge dominated jet, these models are too narrow (by a factor of ∼ 2) in the region 0.06 -0.32 lt-yrs from the source, even though the jets (spine and/or sheath) in the image plane might appear conformant farther downstream. Furthermore, the synthetic radio images are not edge dominated 0.06 -0.32 lt-yrs from the source, but spine dominated. Analyses that implement these models as physical diagnostics of EHT visibility amplitudes are therefore suspect. Thus, these inner jet characteristics are important considerations before applying simulations to the EHT data.

The Details of Limb Brightening Reveal the Structure of the Base of the Jet in M87 for the First Time

“…It was previously noted that synthetic images of numerically simulated jets (typical of those in the EHT Collaboration library) were much narrower (about a factor of 0.4-0.7) compared to 86 GHz VLBI observations of jets for z 0.25 mas (Punsly 2019;Cruz-Osorio et al 2022). However, the apparent nonexistent limb brightening for z < 0.6 mas could not be quantified in an easy to grasp format since the raw data of the simulations were not made public (Mościbrodzka et al 2016;Chael et al 2019;Punsly 2019).…”

“…It was previously noted that synthetic images of numerically simulated jets (typical of those in the EHT Collaboration library) were much narrower (about a factor of 0.4-0.7) compared to 86 GHz VLBI observations of jets for z 0.25 mas (Punsly 2019;Cruz-Osorio et al 2022). However, the apparent nonexistent limb brightening for z < 0.6 mas could not be quantified in an easy to grasp format since the raw data of the simulations were not made public (Mościbrodzka et al 2016;Chael et al 2019;Punsly 2019). Fortunately, publicly shared synthetic image (Flexible Image Transport System, "FITS") files generated from general relativistic simulations were recently created with the same restoring beam as the 86 GHz VLBI observation in Figure 1 (Cruz-Osorio et al…”

“…The simulated jets have a peak in the middle and the VLBI jet has a deep trough in the middle. The simulated jet also fades too rapidly with z; both properties appear in other published numerically simulated synthetic images (Mościbrodzka et al 2016;Chael et al 2019;Punsly 2019;Fromm et al 2022). The EHT Collaboration have assessed their large library of simulations and have determined that only their simulations of magnetically arrested accretion (MAD) can explain the coarse properties of the annulus and produce a jet with enough power (Event Horizon Telescope Collaboration et al 2019Collaboration et al , 2021.…”

Verification of Radiative Transfer Schemes for the EHT

“…Many of our physical assumptions are fairly established. However, one can identify open challenges with regards to the validity of the theoretical description for what the EHT sees and the connection to larger-scale jet structure (Chael et al 2019;Punsly 2019;Davelaar et al 2019). The GRMHD simulations model the matter as a single fluid that effectively describes the behavior of the protons.…”

Testing the Schwarzschild metric in a strong field region with the Event Horizon Telescope

“…In this paper, we assume the standard thin accretion disk model, i.e., the disk is optically thick and geometrically thin [40][41][42][43][44]. We also neglect the influence of the jet [45] on the black hole image. For the Schwarzschild metric, [46,47] calculated the structure of an optically thick and geometrically thin accretion disk, and [11] simulated a photograph of such black holeaccretion disk system.…”