Astronomy & Astrophysics

All Figures

$\begin{figure} \par\includegraphics[angle=270,width=8cm,clip]{1168fig1.ps} \end{figure}$ Figure 1: Comparison between various flat models and the observational data. The observational data points, shown with error-bars, are obtained from the "gold'' sample of Riess et al. (2004). The most recent points, obtained from HST, are shown in red. (This figure is available in color in electronic form.)
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In the text

$\begin{figure} \par\includegraphics[angle=270,width=17cm,clip]{1168fig2.ps} \end{figure}$ Figure 2: The observed supernova data points in the $\dot{a} - a$ plane for flat models. The error bars for the data points are correlated (see text for detailed description). The solid curves, from bottom to top, are for flat cosmological models with $\Omega _{\rm m} = 0.00, 0.16, 0.32, 0.48, 0.64, 0.80, 1.00$ respectively. The left, middle and right panels show data points for the data sets RIESS, RIESS(w/o HST) and TONRY respectively. The vertical dashed line shows the redshift z = 0.34.
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In the text

$\begin{figure} \par\includegraphics[angle=270,width=15cm,clip]{1168fig3.ps} \end{figure}$ Figure 3: Confidence region ellipses in the $\Omega _{\rm m} - {\cal M}_{1,2}$ plane for flat models with non-relativistic matter and a cosmological constant. The ellipses corresponding to the 68, 90 and 99 per cent confidence regions are shown. The top, middle and bottom rows show data points for the data sets RIESS, RIESS(w/o HST) and TONRY respectively. In the left panels, all the data points in the data set are used. In the middle panel, data points with z < 0.34 are used, while in the right panel, we have used data points with z > 0.34. We have indicated the best-fit values of $\Omega _{\rm m}$ and ${\cal M}_{1,2}$ (with 1 $\sigma$ errors).
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In the text

$\begin{figure} \par\includegraphics[angle=270,width=16.2cm,clip]{1168fig4.ps} \end{figure}$ Figure 4: Confidence region ellipses in the $\Omega _{\rm m} - \Omega _{\Lambda }$ plane for models with non-relativistic matter and a cosmological constant. The ellipses corresponding to the 68, 90 and 99 per cent confidence regions are shown. The confidence regions are obtained after marginalizing over ${\cal M}_{1,2}$ . The dashed line corresponds to the flat model $(\Omega _{\rm m} + \Omega _{\Lambda } = 1)$ . The unbroken slanted line corresponds to the contour of constant luminosity distance, Q(z) = constant. The top, middle and bottom rows show data points for the data sets RIESS, RIESS(w/o HST) and TONRY respectively. In the left panels, all the data points in the data set are used. In the middle panel, data points with z < 0.34 are used, while in the right panel, we have used data points with z > 0.34. The values of the best-fit parameters, with 1 $\sigma$ errors are indicated in the respective panels.
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In the text

$\begin{figure} \par\includegraphics[angle=270,width=16cm,clip]{1168fig5.ps} \end{figure}$ Figure 5: Confidence region ellipses in the $\Omega _{\rm m} - \Omega _{\Lambda }$ plane for models with non-relativistic matter and a cosmological constant, allowing for possibly different ${\cal M}_{1,2}$ for the different redshift subsamples. It is assumed that supernovae at z < 0.34 have ${\cal M}_{1,2}^{\rm low}$ , while those at z > 0.34 have ${\cal M}_{1,2}^{\rm high}$ . The ellipses corresponding to the 68, 90 and 99 per cent confidence regions are shown. The confidence regions are obtained after marginalizing over ${\cal M}_{1,2}$ . The dashed line corresponds to the flat model $(\Omega _{\rm m} + \Omega _{\Lambda } = 1)$ . The dot-dashed line denotes the models having zero deceleration at the present epoch (i.e., q₀ = 0), with the region below this line representing the non-accelerating models. The left, middle and right panels show data points for the data sets RIESS, RIESS(w/o HST) and TONRY respectively. The values of the best-fit parameters, with 1 $\sigma$ errors are indicated in the respective panels.
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In the text

$\begin{figure} \par\includegraphics[angle=270,width=15cm,clip]{1168fig6.ps} \end{figure}$ Figure 6: Confidence region ellipses in the w₀ - w₁ plane for flat models with a fixed value of $\Omega _{\rm m}$ , as indicated in the frames. The confidence regions are obtained after marginalizing over ${\cal M}_{1,2}$ . The ellipses corresponding to the 68, 90 and 99 per cent confidence regions are shown. The square point denotes the equation of state for a universe with a non-evolving dark energy component (the cosmological constant). The unbroken slanted line corresponds to the contour of constant luminosity distance, Q(z) = constant. The top, middle and bottom rows show data points for the data sets RIESS, RIESS(w/o HST) and TONRY respectively. The best-fit values of the fitted parameters w₀ and w₁ are indicated in the panels, alongwith the corresponding errors.
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In the text

$\begin{figure} \par\includegraphics[angle=270,width=16cm,clip]{1168fig7.ps} \end{figure}$ Figure 7: Confidence region ellipses in the $\Omega _{\rm m} - \Omega _{\Lambda }$ plane for models with non-relativistic matter and a cosmological constant for different selection criteria based on extinction for the TONRY data set. The ellipses corresponding to the 68, 90 and 99 per cent confidence regions are shown. The confidence regions are obtained after marginalizing over ${\cal M}_1$ . The dashed line corresponds to the flat model $(\Omega _{\rm m} + \Omega _{\Lambda } = 1)$ . The left panel shows results when only those points with $A_{\rm V} < 0.5$ are included, the middle panel considers only points which have $A_{\rm V} < 0.3$ , while the right panel includes all the points irrespective of the value of $A_{\rm V}$ . The values of the best-fit parameters, with 1 $\sigma$ errors are indicated in the respective panels.
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In the text

$\begin{figure} \par\includegraphics[angle=270,width=8cm,clip]{1168fig1.ps} \end{figure}$	Figure 1: Comparison between various flat models and the observational data. The observational data points, shown with error-bars, are obtained from the "gold'' sample of Riess et al. (2004). The most recent points, obtained from HST, are shown in red. (This figure is available in color in electronic form.)
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