Bibcode
van Dokkum, P. G.; Peletier, R. F.; de Grijs, R.; Balcells, M.
Bibliographical reference
Astronomy and Astrophysics (ISSN 0004-6361), vol. 286, no. 2, p. 415-425
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6
1994
Citations
29
Refereed citations
27
Description
The vertical stellar distribution of the edge-on spiral NGC 6504 is
examined in seven bands (U, B, R, I, J, H, K) by fitting model
distributions to the light profile at seven positions along the major
axis. In the inner parts of the disk the profile is well approximated by
an exponential distribution. At large galactocentric distances, the
profile is much less steep near the equatorial plane, being fitted
better by e.g. a sech distribution. We find an excess of light at large
z values, in all optical bands and at all radii. We confirm the
constancy of the scaleheight as a function of radius. Our best
explanation for the deviations from the sech distribution at small z is
dust extinction in combination with a young disk component. This young
disk component has a very small scaleheight (it is unresolved) and a
smaller scale-length than that of the (thin) disk. The excess at large z
can be modeled by a component that looks very much like the thick disk
in the Galaxy: scaleheight approximately 4 times the scaleheight of the
thin disk, and central surface brightness approximately 1% of the
brightness of the thin disk.