Evolve Me A Cluster of StarS (EMACSS) - version 3.10 By: Poul Alexander (University of Cambridge) Mark Gieles (University of Surrey) Henny Lamers (University of Amsterdam) Holger Baumgardt (University of Brisbane) EMACSS is a numerical integrator that solves for the differential equations: dE/dt = f(N,r,p) = - epsilon*E/t_rh' dN/dt = g(N,r,p) = - xi*N/t_rh' drh/dt = h(N,r,p) = mu*r/t_rh' drc/dt = h(N,r,p) = delta*r/t_rh' dmm/dt = i(N,r,p) = gamma*mm/t_rh' dk/dt = h(N,r,p) = lambda*r/t_rh' where epsilon = -lambda+mu+2xi xi = f(N,r,rt) mu = f(rh,rt,rc,N,kappa) delta = f(t_rh,t_rc,N,xi) lambda = f(rc,rh,kappa) gamma = f(N,r,rt,t) t_rh' = t_rh/psi(t) p is an array of variables defining the conditions at any given time. psi is a decreasing function of time. zeta defines the fractional flow of energy per half-mass relaxation time and stellar evolution. Full documentation is available in Alexander & Gieles 2012, Gieles, Alexander, Lamers and Baumgardt 2013, and Alexander, Gieles, Lamers and Baumgardt 2014. The options to specify a cluster (initial number of stars, half mass radius) can be specified with appropriate options (see below) The output is printed directly onto the command line; we therefore suggest piping this output into a file or plotting package. emacss [options] > [output] Although note that the output is formatted (see 'head' for the format of output files. Options: -help: Displays this file. -version: Displays the current version number and version log. -o: (Output) N-body or Real units. 0=N-body (see Heggie & Mathieu 1986) 1=Real [parsec, solar masses, Myr] 2=Real and N-body alternating -N: initial number of stars in cluster. -r: initial half-mass radius of cluster. -m: mean mass of stars [solar masses]. -R: initial ratio of half-mass to Jacobi radius. -g: Galaxy type: 0 - isolated, 1 = point mass, 2 = isothermal -M: mass of point mass galaxy around which the cluster is in orbit [units set by -o]. -d: distance to the point mass galaxy around which the cluster is in orbit [units set by -o]. -v: Orbital velocity of cluster around galaxy. [units set by -o] -z: value for zeta. Defaults to 0.111 for equal mass clusters. -s: Stellar Evolution flag (0 = off, equal mass, 1 = on, IMF). -u: Upper limit of IMF (M_sun) -l: Lower limit of IMF (M_sun) -f: (Experimental) Dynamical Friction flag (0 = off, 1 = on). Tidal field is specified first by MG and RG, if these are provided. If one or both are missing, the code will first attempt to use orbital velocity, then filling factor rhrj. When options are not defined a 64k isolated cluster is used. If used to represent clusters of equal mass stars, the code is only accurate from the start (i.e., throughout core collapse. The default output is N-body units. If option 2 is used N-body and real units alternate. Happy evolving!