We investigate the presence and spatial characteristics of the jet base emission in M87* at 230 GHz, enabled by the significantly enhanced (u,v) coverage in the 2021 Event Horizon Telescope (EHT) observations. The integration of the 12−m Kitt Peak Telescope (USA) and NOEMA (France) stations into the array introduces two critical intermediate-length baselines to SMT (USA) and IRAM 30−m (Spain), providing sensitivity to emission structures at spatial scales of ∼250 μas and ∼2500 μas (∼ 0.02 pc and ∼ 0.02 pc). Without these new baselines, previous EHT observations of the source in 2017 and 2018 lacked the capability to constrain emission on large scales, where a “missing flux” of order ∼1 Jy is expected to reside. To probe these scales, we analyzed closure phases–robust against station-based gain calibration errors–and model the jet base emission using a simple Gaussian component offset from the compact ring emission at spatial separations > 100 μas. Our analysis revealed a Gaussian feature centered at (ΔRA ≈ 320 μas, ΔDec. ≈ 60 μ as), projected separation of ≈ 5500 AU, with an estimated flux density of only ∼60 mJy, implying that most of the missing flux identified in previous EHT studies had to originate from different, larger scales. Brighter emission at the relevant spatial scales is firmly ruled out, and the data do not favor more complex models. This component aligns with the inferred position of the large-scale jet and is therefore physically consistent with the emission of the jet base. While our findings point to detectable jet base emission at 230 GHz, the limited coverage provided by only two intermediate baselines limits our ability to robustly reconstruct its morphology. Consequently, we treated the recovered Gaussian as an upper limit on the jet base flux density. Future EHT observations with expanded intermediate baseline coverage will be essential to constrain the structure and nature of this component with higher precision.
Sagittarius A* ( the supermassive black hole at the center of the Milky Way, provides a unique laboratory to study accretion dynamics and plasma processes near the event horizon. We investigated the variability and polarization properties of using ALMA observations during the 2018 Event Horizon Telescope campaign. We analyzed high-cadence full-polarization light curves from ALMA at millimeter wavelengths, performed time-series analysis, and investigated the temporal behavior during an X-ray flare observed by on 2018 April 24. The variability characteristics are compared with expectations from standard accretion flow models. Chandra We find low variability in total intensity (σ/μ < 10%), but significantly higher variability in linear and circular polarization (∼ 30% and ∼ 50%, respectively). A time-series analysis reveals red-noise variability, with power spectral densities between -2 and -3 across all Stokes parameters. Polarized intensity shows stable intra-day timescales, while total intensity exhibits more variable timescales, suggesting distinct emission regions, with polarization likely arising from a coherent structure. On April 24, a statistically significant inter-band delay in polarized intensity coincides with a near-simultaneous X-ray and millimeter peak that deviates from the typical delayed flare scenario. This event also features enhanced millimeter variability and coherent polarization loop evolution. The observed simultaneity challenges standard models of transient synchrotron emission with cooling delays, favoring instead a scenario of continuous energy injection in an optically thin region. Our results offer new constraints on the physical mechanisms driving variability in and provide key observational input for refining theoretical models of accretion and plasma behavior in the vicinity of supermassive black holes.
Space telescopes maintain optical alignment through periodic, resource-intensive wavefront calibration, leaving the optical state unobserved between corrections. We propose treating onboard engineering telemetry as an opportunistic wavefront sensor. Specifically, the high-cadence thermal and pointing signals already recorded by the James Webb Space Telescope may suffice to recover spatially resolved optical path difference at nanometer precision, without dedicated measurements. Our framework uses a two-stage gradient boosting regressor. It predicts optical path difference residuals for each mirror segment in a low-dimensional principal component basis. The model is trained and evaluated using data captured on-orbit during six months. Based on this limited data, optical path difference inference has high statistical significance in 13 out of 18 mirror segments. In 6 mirror segments, the model achieves explained variance above 50%. These results demonstrate feasibility for telemetry-driven wavefront estimation, as a low-overhead sensing modality. The study suggests a potential to support continuous monitoring and calibration scheduling for large segmented observatories.
Context. The archetypal blazar 3C 279 has a prominent relativistic jet and strong broadband variability across the electromagnetic spectrum. In April 2017, the Event Horizon Telescope (EHT) observed 3C 279 with an unprecedented angular resolution of about 20 μas, accompanied by one of the most extensive quasi-simultaneous multiwavelength (MWL) campaigns ever conducted, spanning from radio to TeV γ -ray energies. Aims. Taking advantage of this comprehensive MWL dataset, we investigated the physical processes governing 3C 279, with a particular focus on the formation, collimation, and acceleration of its relativistic jet and on the origin of its high-energy emission, including the underlying particle-acceleration mechanisms. Methods. We analyzed individual observations and multiband light curves. We also constructed a new quasi-simultaneous spectral energy distribution covering frequencies from the radio band to very high-energy (VHE) γ rays. We further performed a phenomenological modeling using the turbulent extreme multi-zone (TEMZ) model to constrain the fundamental physical properties of the source. Results. The EHT observations reveal a clear flux increase in the innermost core between April 5 and 11, 2017. Over a broader time span, radio observations at longer wavelengths reveal concurrent enhancements in the core flux and polarization around mid-April, coinciding with the ejection of a superluminal knot moving at (25 ± 2) c . Record UV–optical flares with strong polarization variability occurred in late March, followed by high-energy γ -ray activity that declined before the end of the EHT observing period. During this time, the source remained in a low X-ray state and exhibited no detectable VHE emission. Conclusions. The results of the TEMZ modeling indicate that the broadband spectrum and variability of 3C 279 might be explained with a jet scenario in which turbulent plasma cells are compressed by a stationary conical shock. Nonetheless, alternative interpretations, such as magnetic reconnection or a moving shock-in-jet event, remain possible. This coordinated MWL campaign advances our understanding of the origin of the jet and γ -ray emission in the blazar 3C 279, and it also provides a comprehensive publicly available dataset that will serve as a valuable reference for future studies.
With the success of static black-hole imaging, the next frontier is the dynamic and 3D imaging of black holes. Recovering the dynamic 3D gas near a black hole would reveal previously-unseen parts of the universe and inform new physics models. However, only sparse radio measurements from a single viewpoint are possible, making the dynamic 3D reconstruction problem significantly ill-posed. Previously, BH-NeRF addressed the ill-posed problem by assuming Keplerian dynamics of the gas, but this assumption breaks down near the black hole, where the strong gravitational pull of the black hole and increased electromagnetic activity complicate fluid dynamics. To overcome the restrictive assumptions of BH-NeRF, we propose PINeRF , a physics-informed approach that uses differentiable neural rendering to fit a 4D (time + 3D) emissivity field given EHT measurements. Our approach jointly reconstructs the 3D velocity field with the 4D emissivity field and enforces the velocity as a soft constraint on the dynamics of the estimated emissivity. In experiments on simulated data, we find significantly improved reconstruction accuracy over both BH-NeRF and a totally physics-agnostic approach. We demonstrate how our method can be used to estimate other physics parameters of the black hole, such as its spin.
Event Horizon Telescope (EHT) images of the supermassive black hole M87* depict an asymmetric ring of emission. General relativistic magnetohydrodynamic (GRMHD) models of M87* and its accretion disk predict that the amplitude and location of the ring's peak brightness asymmetry should fluctuate due to turbulence in the source plasma. We compare the observed distribution of brightness asymmetry amplitudes to the simulated distribution in GRMHD models, across varying black hole spin a(*). We show that, for strongly magnetized (MAD) models, three epochs of EHT data marginally disfavor divided by a(*)divided by less than or similar to 0.2. This is consistent with the Blandford-Znajek model for M87's jet, which predicts that M87* should have nonzero spin. We show quantitatively how future observations could improve spin constraints and discuss how improved spin constraints could distinguish between differing jet-launching mechanisms and black hole growth scenarios.
We present the first Event Horizon Telescope 1.3 mm observations of the supermassive binary black hole candidate OJ 287. The observations achieved an unprecedented angular resolution of 18 μas and reveal significant structural and polarization variability over just five days, marking the shortest timescale on which such changes have been directly imaged in this source. The inner jet exhibits a twisted ridgeline structure, with features displaying apparent superluminal motions up to about 22 c. The linear polarization maps reveal three main polarized features whose electric-vector position angles (EVPAs) change substantially over the time span of our observations, including a component with a radial polarization consistent with being produced by a recollimation shock. Most notably, we directly resolved two innermost jet components whose EVPAs rotate in opposite directions. The faster component, moving at 2.4 ± 0.9 μas/day (17.4 ± 6.5 c), exhibits counterclockwise EVPA swings of roughly 3.7° per day, while the slower component, with a proper motion of 1.4 ± 0.3 μas/day (10.2 ± 2.2 c), rotates clockwise at approximately 2.5° per day. Previous studies inferred helical magnetic fields in AGN jets from time-resolved or integrated polarization variability but lacked the angular resolution to directly image this effect. Our results provide spatially resolved evidence that a helical magnetic field threads the jet’s collimation and acceleration zone, ruling out models based on the superposition of unresolved components. Our analysis suggests that propagating shocks interact with a Kelvin–Helmholtz plasma instability, illuminating different phases of the helical magnetic field and producing the observed polarization spatial and temporal variability. Moreover, our model naturally accounts for the more rapid polarization rotation observed in the faster moving component. Our model predicts even more rapid swings in polarization, which could be tested with future observations featuring a more densely sampled time coverage.
Cloud droplet size plays a key role in precipitation formation, the cloud radiative effect, and the coupling of clouds to atmospheric turbulence. Due to this confluence of processes, measurements of droplet size are critical to our understanding of the climate system. Satellite remote sensing is the primary means of collecting these measurements over the globe and it is generally considered that multi-spectral or polarized measurements are required to isolate droplet size from droplet concentration. Here, we challenge this paradigm. We hypothesize that key information about the droplet size is encoded in the multi-scale structure of multi-angle imagery enabling the retrieval of droplet size from monochrome non-polarized measurements in the visible spectrum. We prove this hypothesis using forward and inverse (i.e., tomographic) 3D radiative transfer modeling based on realistic cloud models. We demonstrate that a vertical profile of droplet effective radius and the 3D volume extinction coefficient of the cloud can be retrieved using high-resolution (↭ 50 m) imagery at nine viewing angles using only the red channel. We attribute this success to the turbulent nature of cumuliform clouds that produces tenuous, optically thin regions at cloud edge that are only detectable at high spatial resolution. Observations of these regions are sensitive to scattering phase function, hence to droplet size, due to the dominance of low-order scattering. Finally, we verify that the addition of multi-spectral measurements in the shortwave infrared improves the tomographic retrieval of both the 1D droplet effective radius profile and the 3D extinction coefficient field through their improved sensitivity to regions where higher-order scattering dominates.
The 2021 Event Horizon Telescope observations resolve the innermost jet region of the blazar 3C279 with unprecedented detail. The reconstructed images consistently reveal a compact core elongated nearly orthogonal to the large-scale jet axis. This rarely observed morphology recurs across multiple epochs and from 22-230 GHz and is therefore intrinsic rather than an imaging artifact. Geometric model fitting identifies several components with apparent speeds up to 10c, requiring bulk Lorentz factors greater than 10.3 and constraining viewing angles to extremely small values (smaller than one degree). Rest-frame brightness temperatures are systematically low (between 10^9 and 10^10 K), consistent with optically thin emission at 230 GHz. These results suggest that the jet bends toward the observer on sub-parsec scales, producing strong relativistic beaming. Possible drivers of the observed jet bending and temporal evolution include the jet's interaction with the interstellar medium, kink or Kelvin–Helmholtz instabilities, magnetic reconnection near the horizon, or binary-induced precession. However, the current temporal coverage of VLBI data remains insufficient to distinguish between these mechanisms. Continued multifrequency VLBI monitoring will be essential to constraining the dynamics and geometry of the jet base in 3C279.
Supermassive black hole accretion and the ejection of collimated, relativistic jets of plasma are intrinsically dynamic processes shaped by large-scale magnetic fields1-4. Various algorithms have been developed to image these objects at different scales using radio interferometric observations5-8. However, there is a lack of imaging methods that can robustly resolve the temporal variability of the sources at high resolution. Here we present kine, a video reconstruction algorithm for very long baseline interferometry observations of variable sources. The kine algorithm uses a neural representation9 of the video to simultaneously process observations at different times, while learning and leveraging the spatio-temporal correlations present in the data. The algorithm reconstructs polarimetric time-continuous videos from single observations of fast-varying sources, such as horizon-scale observations of Sagittarius A* with the Event Horizon Telescope, or from repeated observations of slowly varying sources. In this work, we demonstrate the latter case, applying kine to multi-epoch Very Long Baseline Array observations of blazar 3C 345 (ref. 10). The time continuity of the video, combined with the resolution and dynamic range improvement achieved over traditional methods, enables the measurement of the local, instantaneous velocity of the plasma in the jet, in contrast to previous methods that track only discrete components. The proposed algorithm and methodology provide a transformative tool for kinematic jet analysis and can be applied to entire monitoring programs, providing a complete kinematic description of hundreds of sources, possibly leading to a reinterpretation of established models.
In very-long baseline interferometric arrays, nearly co-located stations probe the largest scales and typically cannot resolve the observed source. In the absence of a large-scale structure, closure phases constructed with these stations are zero and, since they are independent of station-based errors, they can be used to probe data issues. Here, we show how these trivial closure phases become nonzero with a brightness distribution on smaller scales than their short baseline would suggest. When applied to sources that are made up of a bright compact and large-scale diffuse component, the trivial closure phases directly measure the centroid relative to the compact source and higher-order image moments. We present a technique to measure these image moments with minimal model assumptions and validate it on synthetic Event Horizon Telescope (EHT) data. We then apply this technique to 2017 and 2018 EHT observations of M87* and find a weak preference for extended emission in the direction of the large-scale jet. We also apply it to 2021 EHT data and measure the source centroid about 1 mas northwest of the compact ring, which is consistent with the jet observed at lower frequencies.
The Event Horizon Telescope (EHT) delivered the first image of a black hole by capturing the light from its surrounding accretion flow, revealing structure but not dynamics. Simulations of black hole accretion dynamics are essential for interpreting EHT images, though they are costly to generate and impractical for inference, as exploring many physical configurations remains computationally intractable. Consequently, EHT analyses often resort to comparing observations with libraries of precomputed models. Motivated by this bottleneck, BHCast presents a framework for forecasting black hole plasma dynamics from a single, blurry image, as those captured by the EHT. At its core, BHCast is a neural model that transforms a static image into forecasted future frames, revealing the underlying dynamics hidden within one snapshot. With a multi-scale pyramid loss, we demonstrate how autoregressive prediction can simultaneously super-resolve and evolve a blurry frame into a coherent, high-resolution movie that remains stable over long time horizons. By forecasting dynamics as a first step, we can then extract interpretable spatio-temporal features, such as pattern speed (rotation rate) and pitch angle. This two-step approach makes BHCast more versatile and interpretable than direct inference of such features. Finally, BHCast uses gradient-boosting trees to recover black hole properties from these plasma features, including the spin and viewing inclination angle. We demonstrate the effectiveness of BHCast on simulations of two distinct black hole accretion systems, Sagittarius A* and M87*, by testing on simulated frames blurred to EHT resolution. In addition, we show an application of our forecaster on real EHT images of M87* .
The prediction of climate has been a long-standing problem in contemporary science. One of the reasons stems from a gap in the ability to obtain 3D mapping of clouds, especially shallow scattered clouds. These clouds are strongly affected by mixing processes with their surroundings, rendering their internal volumetric structure highly heterogeneous. These heterogeneous clouds modulate the incoming solar energy and the outgoing long-wave radiation, thereby having a crucial role in the climate system. However, their 3D internal mapping is a major challenge. Here, we combine machine learning and space engineering to enable, for the first time, 3D mapping of scatterers in clouds. We employ ten nano-satellites in formation to simultaneously view the same clouds per scene from different angles and recover the 3D internal structure of shallow scattered clouds, from which we derive statistics, including uncertainty. We demonstrate this on real-world data. The results provide key features for predicting precipitation and renewable energy.
Context. The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading to a number of unique studies on black holes and relativistic jets from active galactic nuclei (AGN). In total, eighteen sources were observed, including the main science targets, Sgr A* and M 87, and various calibrators. Sixteen sources were AGN. Aims. We investigated the morphology of the sixteen AGN in the EHT 2017 data set, focusing on the properties of the VLBI cores: size, flux density, and brightness temperature. We studied their dependence on the observing frequency in order to compare it with the Blandford-Konigl (BK) jet model. In particular, we aimed to study the signatures of jet acceleration and magnetic energy conversion. Methods. We modeled the source structure of seven AGN in the EHT 2017 data set using linearly polarized circular Gaussian components (1749+096, 1055+018, BL Lac, J0132-1654, J0006-0623, CTA 102, and 3C 454.3) and collected results for the other nine AGN from dedicated EHT publications, complemented by lower frequency data in the 2-86 GHz range. Combining these data into a multifrequency EHT+ data set, we studied the dependences of the VLBI core component flux density, size, and brightness temperature on the frequency measured in the AGN host frame (and hence on the distance from the central black hole), characterizing them with power law fits. We compared the observations with the BK jet model and estimated the magnetic field strength dependence on the distance from the central black hole. Results. Our observations spanning event horizon to parsec scales indicate a deviation from the standard BK model, particularly in the decrease of the brightness temperature with the observing frequency. Only some of the discrepancies may be alleviated by tweaking the model parameters or the jet collimation profile. Either bulk acceleration of the jet material, energy transfer from the magnetic field to the particles, or both are required to explain the observations. For our sample, we estimate a general radial dependence of the Doppler factor delta proportional to r(<= 0.5). This interpretation is consistent with a magnetically accelerated sub-parsec jet. We also estimate a steep decrease of the magnetic field strength with radius B proportional to r(-3), hinting at jet acceleration or efficient magnetic energy dissipation.
We report three epochs of polarized images of M87* at 230 GHz using data from the Event Horizon Telescope (EHT) taken in 2017, 2018, and 2021. The baseline coverage of the 2021 observations is significantly improved through the addition of two new EHT stations: the 12 m Kitt Peak Telescope and the Northern Extended Millimetre Array (NOEMA). All observations result in images dominated by a bright, asymmetric ring with a persistent diameter of 43.9 +/- 0.6 mu as, consistent with expectations for lensed synchrotron emission encircling the apparent shadow of a supermassive black hole. We find that the total intensity and linear polarization of M87* vary significantly across the three epochs. Specifically, the azimuthal brightness distribution of the total intensity images varies from year to year, as expected for a stochastic accretion flow. However, despite a gamma-ray flare erupting in M87 quasi-contemporaneously to the 2018 observations, the 2018 and 2021 images look remarkably similar. The resolved linear polarization fractions in 2018 and 2021 peak at similar to 5%, compared to similar to 15% in 2017. The spiral polarization pattern on the ring also varies from year to year, including a change in the electric vector position angle helicity in 2021 that could reflect changes in the magnetized accretion flow or an external Faraday screen. The improved 2021 coverage also provides the first EHT constraints on jet emission outside the ring, on scales of less than or similar to 1 mas. Overall, these observations provide strong proof of the reliability of the EHT images and probe the dynamic properties of the horizon-scale accretion flow surrounding M87*.
We investigate the origin of the elliptical ring structure observed in the images of the supermassive black hole M87*, aiming to disentangle contributions from gravitational, astrophysical, and imaging effects. Leveraging the enhanced capabilities of the Event Horizon Telescope (EHT)'s 2018 array, including improved (u,v)-coverage from the Greenland Telescope, we measured the ring's ellipticity using five independent imaging methods, obtaining a consistent average value of tau = 0.08(-0.02)(+0.03) with a position angle of xi = 50.1(-7.6)(+6.2) degrees. To interpret this measurement, we compared it to general relativistic magnetohydrodynamic (GRMHD) simulations spanning a wide range of physical parameters including the thermal or nonthermal electron distribution function, spins, and ion-to-electron temperature ratios in both low- and high-density regions. We find no statistically significant correlation between spin and ellipticity in GRMHD images. Instead, we identify a correlation between ellipticity and the fraction of non-ring emission, particularly in nonthermal models and models with higher jet emission. These results indicate that the ellipticity measured from the M87* emission structure is consistent with that expected from simulations of turbulent accretion flows around black holes, where it is dominated by astrophysical effects rather than gravitational ones. Future high-resolution imaging, including space very long baseline interferometry and long-term monitoring, will be essential to isolate gravitational signatures from astrophysical effects.
Aims. We investigated the polarization and Faraday properties of Messier 87 (M87) and seven other radio-loud active galactic nuclei (AGNs) at λ 0.87 mm (345 GHz) using the Atacama Large Millimeter/submillimeter Array (ALMA). Our goal was to characterize the linear polarization (LP) fractions, measure Faraday rotation measures (RMs), and examine the magnetic field structures in the emission regions of these AGNs. Methods. We conducted full-polarization observations as part of the ALMA Band 7 very long baseline interferometry (VLBI) commissioning during the April 2021 Event Horizon Telescope (EHT) campaign. We analyzed the LP fractions and RMs to assess the nature of Faraday screens and magnetic fields in the submillimeter emission regions. Results. We find LP fractions between 1% and 17% and RMs exceeding 10 5 rad m −2 , which are 1–2 orders of magnitude higher than typically observed at longer wavelengths ( λ >3 mm). This suggests denser Faraday screens or stronger magnetic fields. Additionally, we present the first submillimeter polarized images of the M87 jet and the observed AGNs, revealing RM gradients and sign reversals in the M87 jet indicative of a kiloparsec-scale helical magnetic field structure. Conclusions. Our results provide essential constraints for calibrating, analyzing, and interpreting VLBI data from the EHT at 345 GHz, representing a critical step toward submillimeter VLBI imaging.
Protoplanetary disks are the birthplaces of planets, and resolving their three-dimensional structure is key to understanding disk evolution. The unprecedented resolution of ALMA demands modeling approaches that capture features beyond the reach of traditional methods. We introduce a computational framework that integrates physics-constrained neural fields with differentiable rendering and present RadJAX, a GPU-accelerated, fully differentiable line radiative transfer solver achieving up to 10,000x speedups over conventional ray tracers, enabling previously intractable, high-dimensional neural reconstructions. Applied to ALMA CO observations of HD 163296, this framework recovers the vertical morphology of the CO-rich layer, revealing a pronounced narrowing and flattening of the emission surface beyond 400 au - a feature missed by existing approaches. Our work establish a new paradigm for extracting complex disk structure and advancing our understanding of protoplanetary evolution.
A variety of high-energy astrophysical phenomena are powered by the release-via magnetic reconnection-of the energy stored in oppositely directed fields. Single-fluid resistive magnetohydrodynamic (MHD) simulations with uniform resistivity yield dissipation rates that are much lower (by nearly 1 order of magnitude) than equivalent kinetic calculations. Reconnection-driven phenomena could be accordingly modeled in resistive MHD employing a nonuniform, "effective" resistivity informed by kinetic calculations. In this work, we analyze a suite of fully kinetic particle-in-cell (PIC) simulations of relativistic pair-plasma reconnection-where the magnetic energy is greater than the rest mass energy-for different strengths of the guide field orthogonal to the alternating component. We extract an empirical prescription for the effective resistivity, eta eff=alpha B0 divided by J divided by p/divided by J divided by p+1+entcp+1 , where B0 is the reconnecting magnetic field strength, J is the current density, nt is the lab-frame total number density, e is the elementary charge, and c is the speed of light. The guide field dependence is encoded in alpha and p, which we fit to PIC data. This resistivity formulation-which relies only on single-fluid MHD quantities-successfully reproduces the spatial structure and strength of nonideal electric fields and thus provides a promising strategy for enhancing the reconnection rate in resistive MHD simulations.
The Event Horizon Telescope (EHT) observation of M87* in 2018 has revealed a ring with a diameter that is consistent with the 2017 observation. The brightest part of the ring is shifted to the southwest from the southeast. In this paper, we provide theoretical interpretations for the multi-epoch EHT observations for M87* by comparing a new general relativistic magnetohydrodynamics model image library with the EHT observations for M87* in both 2017 and 2018. The model images include aligned and tilted accretion with parameterized thermal and nonthermal synchrotron emission properties. The 2018 observation again shows that the spin vector of the M87* supermassive black hole is pointed away from Earth. A shift of the brightest part of the ring during the multi-epoch observations can naturally be explained by the turbulent nature of black hole accretion, which is supported by the fact that the more turbulent retrograde models can explain the multi-epoch observations better than the prograde models. The EHT data are inconsistent with the tilted models in our model image library. Assuming that the black hole spin axis and its large-scale jet direction are roughly aligned, we expect the brightest part of the ring to be most commonly observed 90 deg clockwise from the forward jet. This prediction can be statistically tested through future observations.