Astronomy & Astrophysics

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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{1450fig1.eps}\hspace*{6mm} \includegraphics[width=7.8cm,clip]{1450fig2.eps} \end{figure}$ Figure 1: Evolution of the linear bias with no coupling between the galaxy species or to the dark matter present; the number of galaxies is hence conserved. One curve from the right and one curve from the left panel always belong together for one plotted model, twelve models are presented (roman numbers). The left panel shows the bias b evolving for three quadruple of models from the initial values b=2, 1, 0.5 at redshift z=5 to z=0; the curves of each quadruple belong to initially (from upper to lower): r=0.75, 0.5, -0.5, -0.75. In the right panel we depict the corresponding correlation parameter.
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In the text

$\begin{figure} \includegraphics[width=7.8cm,clip]{1450fig3.eps}\hspace*{6mm} \includegraphics[width=7.8cm,clip]{1450fig4.eps} \end{figure}$ Figure 2: Evolution of the relative linear bias between two galaxy species, both starting off at z=10 with b₁=b₂=4. The correlation of one species to the dark matter is always r₁=1, whereas the second species has r₂=0.6,0.4,0.2,0.0,-0.2,-0.4,-0.6 for the curves in the left panel (upper to lower). The initial correlations between the galaxies where chosen to be r₁₂=0.6,0.4,0.2,0.0,-0.2,-0.4,-0.6. The left panel plots the evolution of b₁₂, the right panel r₁₂, same roman numbers correspond to one model. No coupling is present, hence the galaxy number is conserved.
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In the text

$\begin{figure} \par\includegraphics[width=8.1cm,clip]{1450fig5.eps} \end{figure}$ Figure 3: Estimated fluctuations $\left\langle \delta_{\rm m}^2 \right\rangle$ , Eq. (45), of the dark matter density field for different cutoffs $R_{\rm int}$ using the PD96 prescription for the non-linear clustering regime; see Sect. 4 for cosmological parameters.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{1450fig6.eps} \end{figure}$ Figure 4: Weighting factors $w\left (k\right )$ (in arbitrary units, see Eq. (47)) for different redshifts, the window $\tilde{W}\left(k\right)$ was set to one. The weight maximum stays roughly at the same scale in the plotted redshift interval; the peak is quite broad however. Also plotted here is the window function $\left\vert\tilde{W}\left(k\right)\right\vert^2$ (not normalised) of a top hat $W\left (r\right )$ with $R_{\rm int}=100~\rm kpc/h$ which would cut-off the weights beyond $k_{\rm int}/2\pi=10~\rm Mpc^{-1}~h$ . See Sect. 4 for cosmological parameters; the PD96 prescription was used for non-linear regime.
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In the text

$\begin{figure} \par\hspace*{2mm}\includegraphics[width=7.3cm,clip]{1450fig7.eps}... ...ps}\hspace*{7mm} \includegraphics[width=7.1cm,clip]{1450fig12.eps} \end{figure}$ Figure 5: Example evolutionary tracks of two galaxy populations POPI and POPII subject to different "interactions''. All scenarios share same initial conditions at z=2 (POPI: $b_{\rm I}=4$ , $r_{\rm I}=0.5$ ; POPII: $b_{{\rm II}}=2$ , $r_{{\rm II}}=0$ ; $r_{{\rm I/II}}=0.5$ ). Depicted are as a function of redshift (upper to lower row): bias factors $b_{\rm I}$ and $b_{{\rm II}}$ with respect to dark matter, correlations $r_{\rm I}$ and $r_{{\rm II}}$ to the dark matter field, and correlation $r_{{\rm I/II}}$ between the two galaxy fields (Sects. 4.2 and 4.3 for details). Left column (linear couplings): (arbitrary units) M0: interaction free case; MA: constant creation of galaxies with $A_{\rm I}=A_{{\rm II}}=10$ ; MB: POPII galaxies being transformed to POPI galaxies with $B_{\rm I}^{{\rm II}}=-B_{{\rm II}}^{{\rm II}}=10$ ; MC: linear coupling of both POPI and POPII to dark matter field with $C_{\rm I}=C_{{\rm II}}=10$ . Right column (quadratic couplings): (arbitrary units) M0: interaction free evolution; MD: "colliding'' POPII galaxies are transfered to POPI with $D_{\rm I}^{{\rm II~II}}=-D_{{\rm II}}^{{\rm II~II}}=10^{-4}$ ; ME: both populations are coupled to $\rho _{\rm m}^2$ with $E_{\rm I}=E_{{\rm II}}=1$ ; MF: POPI galaxies are produced by $\Phi _{\rm I}\propto {n}_{{\rm II}}\rho _{\rm m}$ as much as POPII galaxies are destroyed, $F_{\rm I}^{{\rm II}}=-F_{{\rm II}}^{{\rm II}}=0.1$ .
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In the text

$\begin{figure} \par\includegraphics[width=7.2cm,clip]{1450fig13.eps} \end{figure}$ Figure 6: Sketch illustrating the effect of clustering and correlation on the mean interaction rate $\left\langle \Phi \right\rangle$ , thus mean density evolution for quadratic couplings ("collisions'') $\Phi _{12}\propto n_1n_2$ between bright and dark particles. The space is divided into two cells only whose size corresponds to some typical interaction distance $R_{\rm int}$ ; interactions take place between particles within the same cell. From top to bottom: homogeneous distribution, strong clustering and high correlation between particles, strong clustering and high anti-correlation between particles. Strong clustering and high correlation obviously results in the highest interaction rate and hence influences the mean density evolution the most.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{1450fig14.eps} \end{figure}$ Figure 7: Evolutionary tracks of the bias factor with respect to the dark matter of two galaxy populations POPI and POPII for two scenarios MX and MY (initially at z=1: deterministic bias $b_{\rm I}=b_{{\rm II}}=1.2$ , $\bar{n}_{\rm I}=1$ and $\bar{n}_{{\rm II}}=10^{-1}$ ). Both scenarios assume that collisions of POPII galaxies create POPI with $D_{\rm I}^{{\rm II~II}}=-D_{{\rm II}}^{{\rm II~II}}\equiv D$ ; colliding galaxies are removed. MX: sets $\left\langle \delta_{\rm m}^2 \right\rangle=0$ or equivalently $\widehat{b_{\rm I} b_{{\rm II}} r_{{\rm I/II}}}=0$ and D=0.1; MY: sets $\left\langle \delta_{\rm m}^2 \right\rangle$ according to Fig. 3 with $\rm R_{\rm int}=1$ Mpc and D=0.01 in order to have roughly the same evolution of $\bar{n}_{\rm I}$ and $\bar{n}_{{\rm II}}$ as MX.
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In the text

$\begin{figure} \par\includegraphics[width=8.1cm,clip]{1450fig5.eps} \end{figure}$	Figure 3: Estimated fluctuations $\left\langle \delta_{\rm m}^2 \right\rangle$ , Eq. (45), of the dark matter density field for different cutoffs $R_{\rm int}$ using the PD96 prescription for the non-linear clustering regime; see Sect. 4 for cosmological parameters.
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