The calibration of the RGB Tip as a Standard Candle*
Extension to Near Infrared colors and higher metallicity
INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: email@example.com
2 Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: firstname.lastname@example.org
Accepted: 28 April 2004
New empirical calibrations of the Red Giant Branch Tip in the I, J, H and K bands based on two fundamental pillars, namely ω Centauri and 47 Tucanae, have been obtained by using a large optical and near infrared photometric database. Our best estimates give , , and at (ω Cen) and , , and at (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 ()).
Key words: distance scale / globular clusters: individual: NGC 5139; NGC 104 / stars: Population II / Magellanic Clouds
© ESO, 2004