Bibcode
                                    
                            del Rio, M. S.; Brinks, E.; Cepa, J.
    Referencia bibliográfica
                                    "IX Latin American Regional IAU Meeting, "Focal Points in Latin American Astronomy", held in Tonantzintla, Mexico, Nov 9-13, 1998, Eds: Aguilar, A.; Carramiñana, A.; Revista Mexicana de Astronomia y Astrofisica Serie de Conferencias, p. 121."
Fecha de publicación:
    
                        7
            
                        2001
            
  Número de citas
                                    0
                            Número de citas referidas
                                    0
                            Descripción
                                    We present high resolution (15'' and 2.5 km/s) HI observations of the S0
gal axy NGC 404. We derive an HI mass of MHI = 6.7 ×
107 Msolar, in good agreement with previous
measurements. The HI is distributed in a broad annulus and extends out
to a diameter of 9', well beyond the optical diameter of 6'. The
velocity field is regular and shows, surprisingly, a declining rotation
curve. This decline is purely Keplerian, strongly suggesting that all
the mass is contained within the inner 200''.