pro prob_z,logzn,lprobz ; This routine accepts a vector logzn(npt) containing values of log(Z) ; (relative to solar abundance), and returns lprobz(npt), containing the ; ln of the unnormalized probability that a star has this logz, per unit logz. ; Method is evaluation of a polynomial with linear extension to extreme ; values of logz. The polynomial was derived from a simple fit to a histogram ; of abundance values from Nordstrom et al. 2001, obtained through Vizier ; and read with the routine rd_nord.pro. ; constants cc=[6.79395,-3.50625,-14.5389,-4.41683,6.50095,4.97298,0.886019,-0.125414,$ -0.0377715] zmin=-3. slmin=3. zmax=0.9 slmax=-20. lp0=-3.8 ; get sizes npt=n_elements(logzn) lprobz=fltarr(npt) s=where(logzn ge zmin and logzn le zmax,ns) if(ns gt 0) then lprobz(s)=poly(logzn(s),cc) s=where(logzn lt zmin,ns) if(ns gt 0) then lprobz(s)=lp0+(logzn(s)-zmin)*slmin s=where(logzn gt zmax,ns) if(ns gt 0) then lprobz(s)=lp0+(logzn(s)-zmax)*slmax end