Galactic bulges from Hubble Space Telescope near-infrared camera multi-object spectrometer observations:: The lack of r1/4 bulges

被引:150
作者
Balcells, M
Graham, AW
Domínguez-Palmero, L
Peletier, RF
机构
[1] Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain
[2] Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England
关键词
galaxies : fundamental parameters; galaxies : nuclei; galaxies : photometry; galaxies : spiral; galaxies : structure;
D O I
10.1086/367783
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We use Hubble Space Telescope (HST) near-infrared imaging to explore the shapes of the surface brightness profiles of bulges of S0-Sbc galaxies at high resolution. Modeling extends to the outer bulge via bulge-disk decompositions of combined HST-ground-based profiles. Compact, central unresolved components similar to those reported by others are found in similar to84% of the sample. We also detect a moderate frequency (similar to34%) of nuclear components with exponential profiles that may be disks or bars. Adopting the Sersic r(1/n) functional form for the bulge, none of the bulges have an r(1/4) behavior; derived Sersic shape indices are <n>=1.7+/-0.7. For the same sample, fits to near-infrared ground-based profiles yield Sersic indices up to n=4-6. The high n of ground-based profiles are the result of nuclear point sources blending with the extended light of the bulge because of seeing. The low Sersic indices are not expected from violent relaxation in mergers.
引用
收藏
页码:L79 / L82
页数:4
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