Astron. Astrophys. 330, 453-463 (1998)

The stellar content of the Sagittarius Dwarf Galaxy ^*

G. Marconi ¹, R. Buonanno ¹, M. Castellani ^{1, 2}, G. Iannicola ¹, P. Molaro ³, L. Pasquini ⁴ and L. Pulone <sup>1

1</sup> Osservatorio Astronomico di Roma, Via dell'Osservatorio 2, Monte Porzio Catone, I-00040 Roma, Italy ([marconi,buonanno,mkast,iannicola,pulone]@coma.mporzio.astro.it)
² Universita' "La Sapienza", Istituto Astronomico, Via Lancisi 29, I-00161 Roma, Italy
³ Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, I-34131 Trieste, Italy
⁴ ESO, La Silla

Received 17 March 1997 / Accepted 4 September 1997

Abstract

We present V,I deep CCD photometry for three fields of the dwarf galaxy in Sagittarius (Sgr), located at l=5.6^o, b=-14.1^o. One of the fields is centered on the globular cluster NGC 6715 (M54), which lies in one of the dense clumps of the Sgr galaxy. Comparing the CMD of Sgr with those of globular clusters which are believed to be kinematically associated with the dwarf galaxy (Da Costa & Armandroff 1995), we conclude that the stellar population of Sgr presents a spread in metallicity of -0.71 [Fe/H] -1.58, and that the dominant population ( 10 Gyr old) is extremely similar to the star content of the associated globular cluster Terzan 7. The estimated distance to Sgr is d 24.55 Kpc.

Key words: techniques: photometry stars: HR-diagrams stars: luminosity function galaxies: irregular galaxies: stellar content

* Based on observations collected at the European Southern Observatory, La Silla, Chile.

Send offprint requests to: G. Marconi

© European Southern Observatory (ESO) 1998

Online publication: January 16, 1998
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