One-dimensional collapse: dependence of various quantities on the perturbation length scale L for simulations without (•), with ( × ) cooling and heating, and with cooling and heating and thermal conduction ( + ). Panel A): central temperature (the dotted line represents T_c ∝ L^-0.38; Panel B): central hydrogen number density (the dotted line represents n_H ∝ L^2.38); Panel C): core size (the dotted line represents λ° ∝ L^-1.38); Panel D): temperature at the core boundary (the dotted line represents T° ∝ L³). In the upper panels the data points with thermal conduction are identical to those without and are therefore omitted.