Bibcode
Tikhonov, N. A.; Galazutdinova, O. A.; Aparicio, A.
Referencia bibliográfica
Astronomy and Astrophysics, v.401, p.863-872 (2003)
Fecha de publicación:
4
2003
Revista
Número de citas
20
Número de citas referidas
19
Descripción
We report V -band and I -band CCD stellar and surface photometry of the
galaxy NGC 404 , taken with HST WFPC2 and the 2.5 m Nordic telescope.
The colour-magnitude diagram for the stars in this galaxy is typical of
that of spheroidal systems (i.e. it lacks luminous, young stars but
contains a large number of Asymptotic Giant Branch (AGB) and Red Giant
Branch (RGB) stars). The disk of the galaxy is mostly dominated by red
giant stars while its bulge consists of both the AGB and RGB population.
Using the distance indicator technique, based on the tip of the red
giant branch (TRGB), we find a distance of 3.42 +/- 0.25 Mpc for this
galaxy. Global photometric characteristic of this galaxy were then
measured out to a radius of 3arcmin , giving V = 10fm04 and I = 8fm95 .
We find (V-I) = 0.3 for the nucleus of NGC 404. The integral colour of
the galaxy changes slightly along the radius, and its mean value is
(V-I) = 1.1. On the HST images situated at 9arcmin from the galaxy
center there are many red giants. This means that the size of the disk
of NGC 404 exceeds 20 kpc. The value of the mean metallicity of the red
giants in the disk is [Fe/H] = -1.11.