%0 Generic %1 einasto2020evolution %A Einasto, Jaan %A Hütsi, Gert %A Liivamägi, L. J. %A Einasto, Maret %D 2020 %K tifr %T Evolution of skewness and kurtosis of cosmic density fields %U http://arxiv.org/abs/2011.13292 %X We perform numerical simulations of the evolution of the cosmic web for the conventional $Łambda$CDM model in box sizes $L_0=256,~512,~1024$~\Mpc. We calculate models, corresponding to the present epoch $z=0$, and to redshifts $z=1,~3,~5,~10,~30$. We calculate density fields with various smoothing levels to find the dependence of the density field on smoothing. We calculate PDF and its moments -- variance, skewness and kurtosis. The dimensionless skewness $S$ and the dimensionless kurtosis $K$ characterise symmetry and flatness properties of the 1-point PDF of the cosmic web. Relations $S =S_3 \sigma$, and $K=S_4 \sigma^2$ are now tested in standard deviation $\sigma$ range, $0.015 10$, and in redshift $z$ range $0 z 30$. Reduced skewness $S_3$ and reduced kurtosis $S_4$ described in log-log format. Data show that these relations can be extrapolated to earlier redshifts $z$, and to smaller $\sigma$, as. well as to smaller and larger smoothing lengths $R$. Reduced parameters depend on basic parameters of models. The reduced skewness: $S_3 = f_3(R) +g_3(z)\,\sigma^2$, and the reduced kurtosis: $S_4 = f_4(R) +g_4(z)\,\sigma^2$, where $f_3(R)$ and $f_4(R)$ are parameters, depending on the smoothing length, $R$, and $g_3(z)$ and $g_4(z)$ are parameters, depending on the evolutionary epoch $z$. The lower bound of the amplitude parameters are, $f_3(R) 3.5$ for reduced skewness, and $f_4(R) 16$ for reduced kurtosis, for large smoothing lengths, $R32$~\Mpc. With decreasing smoothing length $R$ the skewness and kurtosis values for given redshift $z$ turn upwards.

@misc{einasto2020evolution, abstract = {We perform numerical simulations of the evolution of the cosmic web for the conventional $\Lambda$CDM model in box sizes $L_0=256,~512,~1024$~\Mpc. We calculate models, corresponding to the present epoch $z=0$, and to redshifts $z=1,~3,~5,~10,~30$. We calculate density fields with various smoothing levels to find the dependence of the density field on smoothing. We calculate PDF and its moments -- variance, skewness and kurtosis. The dimensionless skewness $S$ and the dimensionless kurtosis $K$ characterise symmetry and flatness properties of the 1-point PDF of the cosmic web. Relations $S =S_3 \sigma$, and $K=S_4 \sigma^2$ are now tested in standard deviation $\sigma$ range, $0.015 \le \sigma \le 10$, and in redshift $z$ range $0 \le z \le 30$. Reduced skewness $S_3$ and reduced kurtosis $S_4$ described in log-log format. Data show that these relations can be extrapolated to earlier redshifts $z$, and to smaller $\sigma$, as. well as to smaller and larger smoothing lengths $R$. Reduced parameters depend on basic parameters of models. The reduced skewness: $S_3 = f_3(R) +g_3(z)\,\sigma^2$, and the reduced kurtosis: $S_4 = f_4(R) +g_4(z)\,\sigma^2$, where $f_3(R)$ and $f_4(R)$ are parameters, depending on the smoothing length, $R$, and $g_3(z)$ and $g_4(z)$ are parameters, depending on the evolutionary epoch $z$. The lower bound of the amplitude parameters are, $f_3(R) \approx 3.5$ for reduced skewness, and $f_4(R) \approx 16$ for reduced kurtosis, for large smoothing lengths, $R\approx 32$~\Mpc. With decreasing smoothing length $R$ the skewness and kurtosis values for given redshift $z$ turn upwards.}, added-at = {2020-12-01T07:00:23.000+0100}, author = {Einasto, Jaan and Hütsi, Gert and Liivamägi, L. J. and Einasto, Maret}, biburl = {https://www.bibsonomy.org/bibtex/26b03b9e67ead79475e44b1d1e136a338/citekhatri}, description = {Evolution of skewness and kurtosis of cosmic density fields}, interhash = {b01fe9737cb266d9c58ed9dac02b2304}, intrahash = {6b03b9e67ead79475e44b1d1e136a338}, keywords = {tifr}, note = {cite arxiv:2011.13292Comment: 11 pages, 8 figures, submitted to Astronomy and Astrophysics}, timestamp = {2020-12-01T07:00:23.000+0100}, title = {Evolution of skewness and kurtosis of cosmic density fields}, url = {http://arxiv.org/abs/2011.13292}, year = 2020 }