Academia.eduAcademia.edu

Figure 7 – uploaded by Simon White

See full PDFdownloadDownload figure
‘ig. 6.— As Figure 5, but for the concentration parameter c.

Figure 5 ‘ig. 6.— As Figure 5, but for the concentration parameter c.

Related Figures (14)

A good numerical approximation to the Q-dependence of the critical threshold for spherical ‘ollapse is given by
A good numerical approximation to the Q-dependence of the critical threshold for spherical ‘ollapse is given by
Fig. 1.— Particle plots illustrating the time evolution of halos of different mass in an Qo = 1, n = —1 cosmology. Box sizes of each column are chosen so as to include approximately the same number of particles. At zo = 0 the box size corresponds to about 6 xX ra99. Time runs from top to bottom. Each snapshot is chosen so that M, increases by a factor of 4 between each row. Low mass halos assemble earlier than their more massive counterparts. This is true for every cosmological scenario in our series.
Fig. 1.— Particle plots illustrating the time evolution of halos of different mass in an Qo = 1, n = —1 cosmology. Box sizes of each column are chosen so as to include approximately the same number of particles. At zo = 0 the box size corresponds to about 6 xX ra99. Time runs from top to bottom. Each snapshot is chosen so that M, increases by a factor of 4 between each row. Low mass halos assemble earlier than their more massive counterparts. This is true for every cosmological scenario in our series.
Fig. 3. The fits to the density profiles of Figure 2, scaled to the virial radius, ra99, of each system and to the critical density of the universe at z = 0. Solid and dashed lines correspond to the low- and high-mass systems, respectively. Note that low-mass systems are denser than high-mass systems near the center, indicating that the characteristic density of a halo increases as the halo mass decreases.
Fig. 3. The fits to the density profiles of Figure 2, scaled to the virial radius, ra99, of each system and to the critical density of the universe at z = 0. Solid and dashed lines correspond to the low- and high-mass systems, respectively. Note that low-mass systems are denser than high-mass systems near the center, indicating that the characteristic density of a halo increases as the halo mass decreases.
Fig. 8 The characteristic density of all halos in our series as a function of the redshift at which half of the final mass is in collapsed progenitors more massive than 10% of the final mass. Solid circles correspond to all our runs with 09 = 1, open circles to our runs with 9 = 0.1 and A = 0, and starred symbols to the CDMA runs (Qo = 0.25, A = 0.75). The solid line shows the “natural” scaling, 6. x Qo(1 + z)° expected if the characteristic density of a halo is directly proportional to the mean matter density of the universe at the time of collapse.
Fig. 8 The characteristic density of all halos in our series as a function of the redshift at which half of the final mass is in collapsed progenitors more massive than 10% of the final mass. Solid circles correspond to all our runs with 09 = 1, open circles to our runs with 9 = 0.1 and A = 0, and starred symbols to the CDMA runs (Qo = 0.25, A = 0.75). The solid line shows the “natural” scaling, 6. x Qo(1 + z)° expected if the characteristic density of a halo is directly proportional to the mean matter density of the universe at the time of collapse.
Fig. 10.— The 6,-deviation from the fits shown in Figure 5 (for f = 0.01) plotted versus the deviation from the mean relation between the collapse redshift, 1+ z..1 (Figure 8), and the mass of a system. Note that systems assembled earlier (later) than the average tend to have characteristic densities above (below) the mean. The correlation between the 6. and 1+ Zo residuals follows the “natural” scaling, Alog 6. = 3Alog(1 + Zou), as shown by the solid line. Only the results corresponding to Q9 = 1 are shown.
Fig. 10.— The 6,-deviation from the fits shown in Figure 5 (for f = 0.01) plotted versus the deviation from the mean relation between the collapse redshift, 1+ z..1 (Figure 8), and the mass of a system. Note that systems assembled earlier (later) than the average tend to have characteristic densities above (below) the mean. The correlation between the 6. and 1+ Zo residuals follows the “natural” scaling, Alog 6. = 3Alog(1 + Zou), as shown by the solid line. Only the results corresponding to Q9 = 1 are shown.
Fig. 12.— Circular velocity profiles of M, halos formed in simulations with different power spectra in an Einstein-de Sitter universe. The curves were computed using eq. 3 and the values of the concentration c obtained from the fits in Figure 9. Radii are in units of the virial radius and circular speeds in units of the circular velocity at the virial radius. Note that, because of the use of linear units, the fact that all curves have the same shape (eq. 3) is not immediately apparent.
Fig. 12.— Circular velocity profiles of M, halos formed in simulations with different power spectra in an Einstein-de Sitter universe. The curves were computed using eq. 3 and the values of the concentration c obtained from the fits in Figure 9. Radii are in units of the virial radius and circular speeds in units of the circular velocity at the virial radius. Note that, because of the use of linear units, the fact that all curves have the same shape (eq. 3) is not immediately apparent.
Related topics:
Organic ChemistryAstrophysical PlasmaGalaxy ClustersCold Dark Matter
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved