http://arxiv.org/abs/1808.08559
We present an effective analytic model that can explain both of the tidally induced shape and spin alignments of the galactic halos with the large-scale tidal fields. We test this model against the numerical results obtained from the Small MultiDark Planck simulation on the galactic mass scale of $0.1\le M/(10^{12}\,h^{-1}\,M_{\odot})\le 5$ at redshift $z=0$. The numerical test clearly demonstrates the success of our model in describing simultaneously and consistently the amplitudes and behaviors of the probability density functions of three coordinates of the shape and spin vectors in the principal frame of the large scale tidal field. Dividing the samples of the galactic halos into multiple subsamples in three different mass ranges and four different types of the cosmic web, and also varying the smoothing scale of the tidal field from $5\,h^{-1}$Mpc to $10,\ 20,\ 30\,h^{-1}$Mpc, we perform repeatedly the numerical tests with each subsample at each scale. Our analytic model is found to match the numerical results without resorting to any fitting adjustment for all the cases of the mass range, smoothing scale and web type. It is particularly noted that the scale and web dependence of the spin flip phenomenon is properly captured by this model.
J. Lee
Tue, 28 Aug 18
40/53
Comments: submitted for publication in ApJS, 27 figures, comments welcome
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