Bibcode
Martinez-Roger, C.; Phillips, J. P.; Sanchez Magro, C.
Referencia bibliográfica
Astronomy and Astrophysics (ISSN 0004-6361), vol. 161, no. 2, June 1986, p. 237-243.
Fecha de publicación:
6
1986
Número de citas
9
Número de citas referidas
9
Descripción
Moderate resolution near-infrared mapping of the M31 bulge component is
presented, and the structure, and radial color index and surface
brightness variations are discussed. The near-infrared surface
brightness, mu(r), is matched well by Hubble and de Vaucouleurs
functions for major axis distances of r greater than 30 arcsec, although
they fail to explain the observed behavior at smaller radii. The
near-infrared radial gradient in mu is steeper than at visual
wavelengths, however, and this is also reflected in color index
variations. The metallicity adduced using single star burst models
appears to be reasonably large at the core (M/H of about 0.2), and
decreases slowly outwards; a result which confirms and supplements
various optical estimates. The present results also confirm a change of
apparent isophotal ellipticity compared with optical wavelengths, with
ellipticity taking a typical value epsilon of about 0.3. It is
postulated that this may be due to observation of a redder stellar
component of the bulge having a flatter oblate spheroidal distribution.