On The Reliability of photometric and spectroscopic traces of halo relaxation

محمد حسین ژولیده حقیقی 

(پژوهشکده نجوم پژوهشگاه دانش های بنیادی IPM )

Abstract: Characterizing the relaxation state of galaxy systems is a necessary step for probing the role of environment and halo dynamics in the evolution of galaxies. In this presentation, we will provide an assessment of the reliability of both the photometric and spectroscopic probes. We quantify the correlations between the halo relaxation or the dynamical age, which is defined based on the halo mass assembly in the cosmological simulations, with two spectroscopic indicators, namely the Anderson Darling statistic of the galaxy velocity distribution, A2, and the velocity-segregation, ∆V. We also talk about the correlation of the halo relaxation with photometric indicators which are primarily the luminosity gap between the two most luminous galaxies within half the virial radius of a group, complemented with the off-set between brightest group galaxies and the luminosity centroid. We will explain how a combination of ∆m12 and off-set, correlates more strongly with the dynamical age of the halo than the A2, thus offering a reliable yet fast and economical method of quantifying the relaxation of galaxy systems.

یکشنبه ۴ اسفند ۱۳۹۸، ساعت ۱۵:۰۰

دانشکده فیزیک، طبقه چهارم تالار پرتوی