Migkas et al. (2021) cluster bulk flow direction/speed be confirmed by an independent method (e.g., kSZ) by EOY 2028?

Resolution criteria This market resolves to YES if, on or before December 31, 2028, a peer-reviewed scientific paper (or a pre-print on arXiv that is subsequently peer-reviewed) is published confirming the large-scale bulk flow direction and/or speed reported by Migkas et al. (2021) using an independent observational method. To qualify as confirmation, the paper must: Utilize an independent method that does not rely on the same galaxy cluster scaling relations analyzed in Migkas et al. (2021) (e.g., using the kinetic Sunyaev-Zel'dovich (kSZ) effect, peculiar velocity reconstructions, or Type Ia supernovae). Report a coherent bulk flow pointing in a direction consistent with the Migkas et al. coordinates of $(l, b) \approx (280^\circ \pm 35^\circ, -15^\circ \pm 20^\circ)$. Confirm a bulk flow speed consistent with their estimate of $\sim 900 \pm 200\text{ km/s}$ extending to at least $500\text{ Mpc}$ ($z \approx 0.12$), at a statistical significance of at least $3\sigma$. Explicitly conclude that the results confirm or are strongly consistent with the bulk flow/anisotropy findings of Migkas et al. (2021). If no such independent confirmation is published by December 31, 2028, or if studies within this timeframe rule out or fail to find statistically significant evidence for this specific bulk flow at these scales, the market resolves to NO. In the event of ambiguity or dispute over whether a study constitutes "confirmation," the market creator will resolve the market based on the consensus of the astrophysics community, or via a public poll if a clear consensus is absent. Background In their 2021 study, "Cosmological implications of the anisotropy of ten galaxy cluster scaling relations" (Migkas et al., A&A 649, A151), the authors utilized up to 570 galaxy clusters to detect a $9%$ spatial variation in the local Hubble constant $H_0$ toward Galactic coordinates $(l, b) \sim (280^\circ, -15^\circ)$ with a statistical significance of $>5\sigma$. This apparent anisotropy can be explained by a cosmic bulk flow of $\sim 900\text{ km/s}$ extending out to at least $\sim 500\text{ Mpc}$ ($z \approx 0.12$). Because such a large and deep bulk flow poses a severe challenge to the standard $\Lambda$CDM cosmological model (which expects bulk flows of $\lesssim 200\text{ km/s}$ at these scales), confirming these results with an independent probe is highly critical. One proposed independent method is the kinetic Sunyaev-Zel'dovich (kSZ) effect, which isolates the Doppler shifting of CMB photons scattered by the free electron plasma in moving clusters to measure their peculiar velocities directly. Other potential independent approaches include large-scale peculiar velocity reconstructions from deep galaxy surveys. This description was generated by AI.