Surface Photometry of Edge-on Galaxies. VI. NGC 4452 and NGC 4762
Abstract
High-resolution photographic surface photometry of a perfectly edge-on lenticular galaxy NGC 4452 has been carried out and its structure was compared with that of another perfectly edge-on lenticular galaxy NGC 4762. The analysis of the family of luminosity profiles both parallel and perpendicular to its galactic plane suggests that, as in the case of NGC 4762, this galaxy consists of four distinct components whose vertical structures are different from each other: the four are the nuclear bulge, the lens, the outer halo, and an unknown extremely thin (a vertical scale length z^bar^ ~ 1.1" = 77 pc) component which is embedded in the lens. The vertical luminosity profile of the lenses of NGC 4452 and NGC 4762 are less steep than a self-gravitating isothermal sheet model of a constant thickness, whereas those of the ordinary spiral galaxies with small bulges, e.g., NGC 4244, NGC 5023, and NGC 5907, are well described by the model described by van der Kruit and Searle in 1981 and 1982. As for the nature of the extremely thin disk components, we give the following possible interpretation. The two galaxies could be classified as early-type barred lenticular galaxies and the extremely thin components should be identified as their bar components. Hence, barred galaxies in general have quite different vertical structures from those of ordinary spiral galaxies. If this is the case, about one-half of lenticulars should have such thin disks. However, it is unclear how common the presence of these thin disks is among lenticulars. Many more observations of edge-on lenticular galaxies with high spatial resolutions are required to clarify the nature of extremely thin components.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1989
- DOI:
- Bibcode:
- 1989ApJ...339..783H
- Keywords:
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- Astronomical Photometry;
- Barred Galaxies;
- Galactic Structure;
- Lenticular Bodies;
- Astronomical Photography;
- Brightness Distribution;
- Galactic Bulge;
- Optical Thickness;
- Astrophysics;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4452;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4762;
- GALAXIES: PHOTOMETRY;
- GALAXIES: STRUCTURE