| Abstract | New empirical calibrations of the Red Giant Branch Tip in the I, J, H and K bands based on two fundamental pillars, namely Ω0 Centauri and 47 Tucanae, have been obtained by using a large optical and near infrared photometric database. Our best estimates give MITRGB = -4.05 ± 0.12, MJTRGB = -5.20 ± 0.16, MHTRGB = -5.94 ± 0.18 and MKTRGB = -6.04 ± 0.16 at [M/H]≃-1.5 (Ω0 Cen) and MITRGB = -3.91 ± 0.13, MJTRGB = -5.47 ± 0.25, MHTRGB = -6.35 ± 0.30 and MKTRGB = -6.56 ± 0.20 at [M/H]≃-0.6 (47 Tuc). With these new empirical calibrations we also provide robust relations of the TRGB magnitude in the I, J, H, and K bands as a function of the global metallicity. It has also been shown that our calibrations self-consistently provide a distance modulus of the Large Magellanic Cloud in good agreement with the standard value ((m-M)0≃ 18.50)). Based on observations collected at ESO, La Silla, Chile. |
