Structural properties of disk galaxies: The intrinsic equatorial ellipticity of bulges
Structural properties of disk galaxies: The intrinsic equatorial ellipticity of bulges
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DOI：
10.1051/0004-6361:20078089
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发表时间：
2008-01
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影响因子：
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通讯作者：
J. Méndez-Abreu;J. Aguerri;E. Corsini;E. Simonneau
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文献类型：
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作者：
J. Méndez-Abreu;J. Aguerri;E. Corsini;E. Simonneau
本文推导了148个无闩S0-Sb星系等限样本的结构参数，研究了凸起与圆盘参数的相关性以及凸起本征赤道椭圆率的概率分布函数。采用一种新的算法（GASP2D）对从2MASS巡天档案中提取的j波段星系图像进行二维凸盘分解。本征椭圆率的PDF是由观测到的凸点椭圆率的分布和凸点与圆盘之间的不对准得到的。约80%的凸起不是扁圆的，而是三轴椭球体。它们在赤道面的平均轴比为=0.85。它们的PDF对形貌、光浓度或光度没有显著的依赖性。这必须用不同的隆起形成情景来解释。
The structural parameters of a magnitude-limited sample of 148 unbarred S0-Sb galaxies were derived to study the correlations between bulge and disk parameters as well as the probability distribution function (PDF) of the intrinsic equatorial ellipticity of bulges. A new algorithm (GASP2D) was used to perform the bidimensional bulge-disk decomposition of the J-band galaxy images extracted from the archive of the 2MASS survey. The PDF of intrinsic ellipticities was derived from the distribution of the observed ellipticities of the bulges and misalignments between the the bulges and disks. About 80% of the observed bulges are not oblate but triaxial ellipsoids. Their mean axial ratio in the equatorial plane is =0.85. There is not significant dependence of their PDF on morphology, light concentration or luminosity. This has to be explained by the different scenarios of bulge formation.