The road to $H_0$, ${\mathrm{\Omega }}_m$, and $w$ with a global neutrino-telescope network

The newly measured correlation between the neutrino and X-ray luminosities of Seyfert galaxies has yielded the first neutrino-based measurement of the Hubble constant. Building on this result, we forecast the reach of a global neutrino-telescope network by 2030, utilizing full-sky IceCube exposures combined with KM3NeT-ARCA and Baikal-GVD. We find that this 2030 configuration sharpens the neutrino-measured Hubble constant from today’s $H_0=66_{-37}^{+44}$ to $H_0=66_{-13}^{+15}$ km s${}^{-1}$ Mpc${}^{-1}$. Additionally, we project that the disk-corona slope of the neutrino X-ray luminosity relation ($L_{\nu }\propto L_X^{\beta }$) will reach $\beta =0.72\pm 0.04$, enabling a $\ge \text{\hspace{0.17em}⁣}5\sigma$ exclusion of the calorimetric value $\beta =1$. Finally, we show that, if a high-redshift population of neutrino sources, such as JWST’s “little red dots,” is identified and obeys the same luminosity relation, we can obtain a new independent measurement of the matter density ${\mathrm{\Omega }}_m$ and the dark energy equation-of-state parameter $w$.