EDP Sciences
Free access
Volume 421, Number 2, July II 2004
Page(s) 603 - 612
Section Galactic structure, stellar clusters and populations
DOI http://dx.doi.org/10.1051/0004-6361:20034498

A&A 421, 603-612 (2004)
DOI: 10.1051/0004-6361:20034498

The distance to NGC 5904 (M 5) via the subdwarf main sequence fitting method

V. Testa1, A. Chieffi2, M. Limongi1, G. Andreuzzi1, 3 and G. Marconi1, 4

1  INAF - OAR, via Frascati 33, 00040 Monteporzio Catone, Italy
2  IASF - CNR, via del Fosso del Cavaliere, 00100, Roma, Italy
3  INAF - TNG, Santa Cruz de La Palma, Canary Islands, Spain
4  ESO - Chile, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19, Chile

(Received 13 October 2003 / Accepted 4 March 2004)

We present a determination of the distance modulus of the globular cluster NGC 5904 (M 5), obtained by means of the subdwarf main-sequence fitting on the (V,V-I) color-magnitude diagram. The subdwarf sample has been selected from the HIPPARCOS catalog in a metallicity range homogeneous with the cluster ([Fe/H] $\simeq$ -1.1). Both the cluster and the subdwarfs have been observed with the same telescope+instrument+filters setup (namely, ESO-NTT equipped with the SUSI2 camera), in order to preserve homogeneity and reduce systematic uncertainties. A set of archival HST data has then been used to obtain a deep and precise ridge line. These have been accurately calibrated in the ground photometric system by using the NTT data and used to fit the cluster distance modulus. By adopting the most commonly accepted values for the reddening, E(B-V) = 0.035 and 0.03, we obtain respectively $\mu_0
= 14.44 \pm 0.09 \pm 0.07$ and $\mu_0 = 14.41 \pm 0.09 \pm 0.07$, in agreement with recent determinations.

Key words: Galaxy: globular clusters: individual: NGC 5904 (M 5) -- stars: distances

Offprint request: V. Testa, testa@mporzio.astro.it

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© ESO 2004