3 The database

Figures 4 show the final CMDs for the 74 GGCs of our database in the F439W and F555W HST flight system. Note that the magnitude and color ranges covered by each figure are always of the same size (though magnitude and color intervals are different), with the exception only of NGC 6397. Typically from a few thousands to about 47 000 (e.g. in NGC 6388) stars have been measured in each cluster.

Table 3 shows an example of the final photometric file.

After the publication of the present paper, all the CMDs, the star positions, the magnitudes in both the F439W and F555W flight system and the B and V standard Johnson system can be retrieved from the Padova Globular Cluster Group Web pages at http://menhir.pd.astro.it. We will also make available the star-count completeness results of the single clusters, upon request to the first author. Anyone who uses the photometric data retrieved from the Web pages and the completeness corrections is kindly asked to cite the present paper.

In the file that gives the photometry we have included two sets of magnitudes in each of four photometric bands. We give magnitudes in the HST flight system (F439W, F555W), and the Johnson B and Vmagnitudes that result from the iterative procedure that uses the Harris (1996) reddening subtraction, as described in Sect. 2.4. We also give magnitudes in both systems before the reddening correction: ( $F439W_{\rm nr}$, $F555W_{\rm nr}$) and ( $B_{\rm nr}$,  $V_{\rm nr}$). In general we would advise the reader to use the $F439W_{\rm nr}$ and $F555W_{\rm nr}$ magnitudes (Cols. 12 and 13). If one needs to work in the Johnson system for highly reddened clusters, however, the only magnitudes which can be safely used are the B and Vmagnitudes resulting from the iterative calibration procedure (Cols. 4 and 5), though we cannot guarantee that the adopted reddening is correct.

Acknowledgements

The present work has been supported by the Italian Ministero della Università e della Ricerca under the program Stellar Dynamics and Stellar Evolution in Globular Clusters and by the Agenzia Spaziale Italiana. ARB wishes to thank the Istituto Nazionale di Astrofisica for support. IRK, SGD, CS, and RMR acknowledge support from the STScI grants GO-6095, GO-7470, GO-8118, and GO-8723.