WiggleZ Dark Energy Survey: Cosmological neutrino mass constraint from blue high-redshift galaxies

The absolute neutrino mass scale is currently unknown, but can be constrained by cosmology. The WiggleZ high redshift, star-forming, and blue galaxy sample offers a complementary data set to previous surveys for performing these measurements, with potentially different systematics from nonlinear structure formation, redshift-space distortions, and galaxy bias. We obtain a limit of $\sum _{}^{}{m}_{\nu }<0.60\mathrm{eV}$ (95% confidence) for $\mathrm{WiggleZ}+\mathrm{Wilkinson}\mathrm{Microwave}\mathrm{Anisotropy}\mathrm{Probe}$. Combining with priors on the Hubble parameter and the baryon acoustic oscillation scale gives $\sum _{}^{}{m}_{\nu }<0.29\mathrm{eV}$, which is the strongest neutrino mass constraint derived from spectroscopic galaxy redshift surveys.

Figure 1

The ratio between the simulated WiggleZ halo power spectrum (from GiggleZ) and the corresponding linear power spectrum (normalized to the first bin) at $z=0.2$ (blue dashed) and $z=0.6$ (black solid) and for luminous red galaxies (dotted red). The vertical lines indicate our fitting range of $k=0.02–0.3h{\mathrm{Mpc}}^{-1}$. Nonlinear corrections are clearly less significant for the high-redshift, low-bias WiggleZ halos than at lower redshifts.

Figure 2

A weighted average of the WiggleZ power spectra in the survey regions and redshifts, and the six models for the best fit cosmology of model F). The models are (A) blue dotted, (B) green dashed, (C) magenta dot-dashed, (D) cyan triple dot-dashed, (E) red long dashed, (F) thick orange solid. The vertical lines are $k=0.02h{\mathrm{Mpc}}^{-1}$ and $k=0.3h{\mathrm{Mpc}}^{-1}$. The divergence between the models at large $k$ is clear and demonstrates the importance of careful modeling.

Figure 3

Upper: Reduced ${\chi }^2$ of models A)–F) fitted to the $N$-body simulation halo catalogue for the GiggleZ fiducial cosmology values. In absence of systematic errors the models should recover the input cosmology with ${\chi }^2/\mathrm{dof}=1$. Lower: Difference in reduced ${\chi }^2$ values when using the GiggleZ fiducial cosmological parameters and the best fit values. The models are (A) blue dotted, (B) green dashed, (C) magenta dot-dashed, (D) cyan triple dot-dashed, (E) red long dashed, (F) thick orange solid.

Figure 4

Upper: Reduced ${\chi }^2$ as a function of $k_{\max }$ for each of the six approaches. Lower: Upper limits on $\sum _{}^{}{m}_{\nu }$ as a function of $k_{\max }$. The models are: A) blue dotted, (B) green dashed, (C) magenta dot-dashed, (D) cyan triple dot-dashed, (E) red long dashed, (F) thick orange solid. The dashed grey line is the lower limit from oscillation experiments, and the black lines are upper limits from $\mathrm{WMAP}+\mathrm{BAO}+H_0$ (dotted) and $\mathrm{WiggleZ}+\mathrm{WMAP}+\mathrm{BAO}+H_0$ (solid).

Figure 5

The relative probability distribution of $\sum _{}^{}{m}_{\nu }$ from fitting model F) with $k_{\max }=0.3h{\mathrm{Mpc}}^{-1}$ for WMAP (dotted orange), $\mathrm{WiggleZ}+\mathrm{WMAP}$ (solid orange), $\mathrm{WMAP}+\mathrm{BAO}+H_0$ (dotted black) and $\mathrm{WiggleZ}+\mathrm{WMAP}+\mathrm{BAO}+H_0$ (solid black). The dashed grey line is the lower limit from oscillation experiments, and the vertical lines are 95% confidence upper limits.