Spatial source distribution of bulges from surface photometry: application to NGC 2841.

Varela, A. M.; Munoz-Tunon, C.; Simmoneau, E.
Bibliographical reference

Astronomy and Astrophysics, v.306, p.381

Advertised on:
2
1996
Number of authors
3
IAC number of authors
2
Citations
17
Refereed citations
17
Description
We tackle here the problem of obtaining the spatial density of sources ρ in the bulge of a spiral galaxy using bidimensional surface photometry. V,R,I,Z CCD images, taken with the 4.2m William Herschel Telescope at seeing limit resolution (0.5"-1.1"), yield the photometric parameters for the galaxy NGC 2841. The necessary procedure prior to obtaining a surface density distribution of luminosity σ corresponding to the bulge is explained and applied to this galaxy. A method is proposed to treat the integral relationship between the spatial distribution ρ(R) and the observed surface distribution σ(r). The analysis of the position angle and ellipticity variations with radius takes to the possible presence of a stellar bar structure within the inner ten arcseconds of the galaxy. In the case of NGC 2841, the misalignment between the position angle of the isophotes corresponding to the bulge and the disc components, gives evidence to support the presence of a non-axisymmetric bulge for the galaxy. For this galaxy, it is necessary to reproduce the light distribution of the bulge geometry consisting of a family of triaxial ellipsoids with variable axial ratios.