The Effect Of Dynamical Interactions On Globular Clusters And Their Integrated Properties

Globular Clusters (GCs) are generally treated as natural validators of simplestellar population (SSP) models. However, there are still some diferences be-tween real GCs and SSPs. In this work we use a direct N-body simulation codeNbody6to study the infuences of dynamical interactions, metallicity and primor-dial binaries on Milky Way globular clusters’ integrated properties. Our modelsstart with N=100,000stars, covering a metallicity range Z=0.00010.02,Stellar evolution and external tidal feld representative for an average Milky WayGC are taken into consideration. A subset of our models contain primordial bi-naries, resulting in a binary fraction as currently observed at a model age of GCs.The integrated colours and Lick indices are calculated using BaSeL and Blueredstellar spectral libraries separately.By including dynamical interactions, our model clusters show integratedfeatures (colours become slightly bluer, Hβ up to0.1A greater and [MgFe]′0.05A smaller) making the clusters appear slightly younger than the model clusterswithout dynamical interactions. This efect is caused mainly by the preferentialloss of low-mass stars which have a stronger contribution to redder passbandsas well as diferent spectral features compared to higher-mass stars. In addition,this efect is larger at lower metallicities. On the contrary, the incorporation ofprimordial binaries reduces this efect.