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تسجيل مستخدم جديدThe dynamical state of galaxy groups and their luminosity content
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تأليف
Hector J. Martinez
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We analyse the dependence of the luminosity function of galaxies in groups (LF) on group dynamical state. We use the Gaussianity of the velocity distribution of galaxy members as a measurement of the dynamical equilibrium of groups identified in the SDSS Data Release 7 by Zandivarez & Martinez. We apply the Anderson-Darling goodness-of-fit test to distinguish between groups according to whether they have Gaussian or Non-Gaussian velocity distributions, i.e., whether they are relaxed or not. For these two subsamples, we compute the $^{0.1}r-$band LF as a function of group virial mass and group total luminosity. For massive groups, ${mathcal M}>5 times 10^{13} M_{odot} h^{-1}$, we find statistically significant differences between the LF of the two subsamples: the LF of groups that have Gaussian velocity distributions have a brighter characteristic absolute magnitude ($sim0.3$ mag) and a steeper faint end slope ($sim0.25$). We detect a similar effect when comparing the LF of bright ($M^{group}_{^{0.1}r}-5log(h)<-23.5$) Gaussian and Non-Gaussian groups. Our results indicate that, for massive/luminous groups, the dynamical state of the system is directly related with the luminosity of its galaxy members.
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