|Constrained Realization Images|
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-more images (from Smoothed Density Fields & Voids)
Constrained Realization Images
These pages include:
High resolution versions of the Figures 1 and 3 of the paper "Simulating the Formation of the Local Galaxy Population" (astro-ph/0111099).
Figure 1 of the paper "Voids in the Simulated Local Universe"
see full size (1036x1036 pixels)
Detailed pictures of various sizes for the dark matter distribution, made by Volker Springel, are available here.
We have carried out two simulations that mimic the Local Universe, CR-TCDM and CR-LCDM. The initial conditions of these simulations have been constrained by the smoothed density field of the 1.2-Jy redshift survey of IRAS galaxies. As a result, the simulations develop the same prominent large-scale structure as observed in the Local Universe, i.e. the N-body models develop structures corresponding to the Great Attractor or the Cetus Wall. Also, clusters like Perseus-Pisces, Hercules-Centaurus, Pavo-Indus-Telescopium, Virgo, or Coma are all found at the right place.
The simulations follow the evolution of a comoving sphere of diameter 416 Mpc/h. In the central region of radius ~ 80 Mpc/h around 53 million particles are used, while the surrounding boundary region is sampled with 20 million particles. The gravitational softening in the high-resolution zone is 20 kpc/h. The simulations have been carried out with the GADGET code on the Garching T3E.
Each of the pictures available on this page shows the projected particle distribution of a slice of thickness 12 Mpc/h through the supergalactic plane. The pictures referred to as high-res-zone have a comoving side length of 170 Mpc/h and show the central high-resolution zone of the simulations. The images labelled full simulation are slices of side length 420 Mpc/h through the full (spherical) simulation volume.
Each of the pictures is available in two color scales (red and blue), and at two different resolutions (400x400 and 1500x1500 pixels). For the 1500x1500 pixel images (size ~ 1Mbyte), you should have a fast internet connection, a large color screen, and a good browser, preferably all three of these. I recommend that you start `netscape' with the `-install' option on 256 color displays, otherwise the colors might be compromised.
In the table below, just click on the links of the images you want to look at. A direct comparison of the low resolution images is also avaliable.
The color scale of the images maps the logarithmic surface mass density of the slices. In each case, the color scale extends from 0.01 times the mean density to the maximum surface density of the slice.
All slices are 30 Mpc/h thick, with normal direction supergalactic SGZ, SGY, SGX respectively. One side of a slice reaches 180 Mpc/h. The inner sphere of radius 90Mpc/h is resolved with higher resolution (factor 40 in mass) than the surrounding zone.
One can distinguish the nearby massive structures such as the Virgo cluster, the Pavo-Indus, Hydra-Centaurus, and Pisces-Perseus complexes. Further out lies the Coma cluster, just within the high-resolution zone.
Left slices show the dark matter distribution only, while right ones show the dark matter distribution with the galaxies obtained from the semi-analytic (SA) code plotted on top of it.
As the SA code follows the history of the high-resolution particles, galaxies mainly remain within the inner sphere. The galaxies' symbols scale in radius with their B band magnitude, in colour with the B-V index.
In these pictures, the luminosity cutoff in the B band is given by the morphological resolution of the simulations: -18.46 in LCDM, -20.61 in TCDM.
Click beneath the picture to get the full size image in different formats.
LCDM projected along Z
TCDM projected along Z
TCDM projected along X
In particular, one can study evolution in the abundances, luminosities, colours and spatial distributions of specific galaxy populations, such as early-type galaxies, star-forming systems, Lyman Break galaxies, starbursts, QSO hosts or Milky Way progenitors.
A particular virtue of the constrained realisations is that the spatial and kinematic distributions of these populations can be compared in detail with those of the corresponding real galaxies in the nearby universe.
The following slides (available in .gif format) illustrate the distribution of some of these populations in our flat, low density constrained realisation (for which Omega_m=0.3, Omega_L=0.7 and h=0.7). The region shown is a slice centred on the supergalacitc plane of thickness 30 Mpc/h. The galaxy population is followed out to a distance of 80 Mpc/h from the centre.
Colour symbols represent galaxies. In each image the size and colour of the symbols encode specific astrophysical properties. Download Details of this encoding.
WARNING : internet transfer rates can be slow, since a single .gif file is 0.9 Mbyte on average.Dark matter distribution
Dark matter distribution z=2.4 : gif
Dark matter distribution z=0.8 : gif
Dark matter distribution z=0. : gif Properties at z=0.
The absolute B magnitude : gif
A short movie shows the galaxy distribution on spherical shells. (caution : the movie will play at the rate of the connection). Projected (4KF) number of galaxies in a 200 km/s shell, from 1000 km/s to 7000 km/s.
Comments to: H. Mathis firstname.lastname@example.org