Spiral Galaxies with WFPC2. III. Nuclear Cusp Slopes
Author(s) -
C. M. Carollo,
M. Stiavelli
Publication year - 1998
Publication title -
the astronomical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.61
H-Index - 271
eISSN - 1538-3881
pISSN - 0004-6256
DOI - 10.1086/300373
Subject(s) - physics , astrophysics , spiral galaxy , galaxy , surface brightness , cusp (singularity) , bulge , fundamental plane (elliptical galaxies) , luminosity , astronomy , elliptical galaxy , lenticular galaxy , geometry , mathematics
In this paper, the third of a series dedicated to the investigation of thenuclear properties of spiral galaxies, we have (i) modelled the WFPC2 F606Wnuclear surface brightness profiles of 41 spiral galaxies presented in Carolloet al. 1997c, 1998 with the analytical law introduced by Lauer et al. 1995, and(ii) deprojected these surface brightness profiles and their analytical fits,so as to estimate the nuclear stellar densities of bulges of spiral galaxies.We find that the nuclear stellar cusps (quantified by the average logarithmicslope of the surface brightness profiles within 0.1''-0.5'') are significantlydifferent for R^1/4-law and exponential bulges. The former have nuclearproperties similar to those of early-type galaxies, i.e. similar values ofnuclear cusps for comparable luminosities, and increasingly steeper stellarcusps with decreasing luminosity. By contrast, exponential bulges have(underlying the light contribution from photometrically distinct, centralcompact sources) comparative shallower stellar cusps, and likely lower nucleardensities, than R^1/4-law bulges.Comment: 22 pages, 8 figures - AJ in pres
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom