Figure 1

The fraction of the total comoving volume of the observable Universe that is available up to a redshift $z$.Reuse & Permissions

Figure 2

The number of modes $N$ within a wave number bin of width $\Delta k=k/10$ centered on $k$ that are available in different cosmological surveys. The thick dashed gray line corresponds to the spectroscopic LRG sample of SDSS [16], while the thick solid line (marked HRG for “high redshift galaxies”) corresponds to a future spectroscopic survey at $2.5<z<3.5$ covering 1000 square degrees with a comoving galaxy density equal to the LRG sample. The thick dark line corresponds to a CMB data set with $f_{\mathrm{sky}}=0.65$. The thin lines show the number of modes accessible in a 21 cm survey (including the limit on large-scale modes due to foreground removal [12]) covering $f_{\mathrm{sky}}=0.65$ within a redshift range spanning a factor of 3 in $(1+z)$, and centered on $z=1.5$, 3.5, and 6.5. For $z\le 1.5$, we have truncated the curves at $k=0.2\mathrm{Mp}{\mathrm{c}}^{-1}$ to illustrate the smaller range of $k$ accessible within the linear regime at lower redshifts [33].Reuse & Permissions

Figure 3

The fractional change in the amplitude of the power spectrum owing to the presence of a massive neutrino (horizontal gray lines, asymptoting towards a constant at high $k$ values). The case shown, $f_{\nu }=0.004$, corresponds to $m_{\nu }=0.05\mathrm{eV}$. For comparison, the limits imposed by cosmic variance on measurements of the power spectrum from the SDSS-LRG and a future 1000 square degree galaxy survey at $2.5<z<3.5$ are marked by the thick dashed and solid gray lines, respectively. The $U$-shaped error curves correspond to an all-sky 21 cm survey [$f_{\mathrm{sky}}=0.65$ over a redshift range spanning a factor of 3 in $(1+z)$] with MWA5000 and a ${10}^3\mathrm{h}$ integration per field (line styles for $z=1.5$, 3.5, 6.5 as in Fig. 2). The noise is plotted in bins of size $\Delta k/k=0.1$. The inset shows these results on logarithmic axes that span a larger dynamic range of achievable precision. The straight thin lines in the inset show the cosmic-variance uncertainty in the power-spectrum measurement owing only to the number of available modes. For $z\le 1.5$, we have truncated the curves at $k=0.2{\mathrm{Mpc}}^{-1}$ to illustrate the smaller range of $k$ accessible within the linear regime at lower redshifts [33].Reuse & Permissions