MR. NILADRI PAUL

Data suggests that central galaxies have narrow width in their luminosity distribution function compared to that of the satellite galaxies. This leads to the debate on whether the luminosity of the centrals is drawn from some special luminosity distribution function. The speaker will show that the assumption of the luminosity of the centrals being the statistical extreme of a universal luminosity function is consistent with the narrow width in their luminosity distribution. In addition to that, this model can consistently predict the luminosity dependence of the two-point clustering of the galaxies. The speaker will show that one needs to incorporate halo-mass dependence in the universal luminosity distribution function to satisfy these requirements. This model reduces the complexity of the standard Halo Occupation Distribution (HOD) and the Conditional Luminosity Distribution Function (CLF) based approaches. The halo-mass dependence of the magnitude-gap between the brightest and the second brightest galaxy in a group will be discussed.