Calibrating the tip of the red giant branch and measuring Magellanic Cloud distances to ∼ 2% exclusively with Gaia

We have calibrated the tip of the red giant branch (TRGB) using our recent catalogue of homogeneous globular cluster (GC) distances. The GC distances were determined via a global joint fit to optical period--Wesenheit relations of their member RR Lyrae stars and type-II Cepheids, anchored by trigonometric parallaxes; all data were taken from the ESA = mission's (early) third data release (GDR3). Using I-band measurements of 48 GCs from P. Stetson's database, we determined M_ I,0 ( = in distance). Calibrating the TRGB using homogeneous, space-based RP photometry of 53 GCs, we found M_ RP,0 ( The stated uncertainties include statistical and systematic effects, including the correlated nature of the GC distances. The robustness of our calibrations was evaluated via tests against small-number statistics and analysis choices. Within the (small) uncertainties, no significant metallicity effect is detected in our sample of old, low-metallicity GCs. We measured ∼ 2% distances to the Large and Small Magellanic Clouds, (48.9± 0.9,kpc) and (60.2± 1.4,kpc), respectively, using a single photometric system: RP (spectro-)photometry from GDR3. Our new TRGB distances, whose absolute scale derives from parallaxes, are fully independent of the well-known detached eclipsing binary (DEB) distances and agree with them to within the uncertainties. Combining our new TRGB and existing DEB distances, we illustrate how additional constraints can be incorporated into the Local Distance Network and obtain H_0=73.52 . Expected improvements thanks to the upcoming fourth -1 ,Mpc^ -1 data release are discussed.