21 research outputs found
RSD measurements from BOSS galaxy power spectrum using the halo perturbation theory model
We present growth of structure constraints from the cosmological analysis of
the power spectrum multipoles of SDSS-III BOSS DR12 galaxies. We use the galaxy
power spectrum model of Hand et al. (2017), which decomposes the galaxies into
halo mass bins, each of which is modeled separately using the relations between
halo biases and halo mass. The model combines Eulerian perturbation theory and
halo model calibrated on -body simulations to model the halo clustering. In
this work, we also generate the covariance matrix by combining the analytic
disconnected part with the empirical connected part: we smooth the connected
component by selecting a few principal components and show that it achieves
good agreement with the mock covariance. Our analysis differs from recent
analyses in that we constrain a single parameter fixing everything
else to Planck+BAO prior, thereby reducing the effects of prior volume and
mismodeling. We find tight constraints on :
and
at $k_{\mathrm{max}} = 0.2\
h^{-1}P_4(k)k_{\mathrm{max}} = 0.4\ h^{-1}k_{\mathrm{max}}$
consistently and reliably remains the main challenge of RSD analysis methods.Comment: 21 pages, 13 figure
Towards Neutrino Mass from Cosmology without Optical Depth Information
With low redshift probes reaching unprecedented precision, uncertainty of the
CMB optical depth is expected to be the limiting factor for future cosmological
neutrino mass constraints. In this paper, we discuss to what extent
combinations of CMB lensing and galaxy surveys measurements at low redshifts
will be able to make competitive neutrino mass measurements
without relying on any optical depth constraints. We find that the combination
of LSST galaxies and CMB-S4 lensing should be able to achieve constraints on
the neutrino mass sum of 25meV without optical depth information, an
independent measurement that is competitive with or slightly better than the
constraint of 30meV possible with CMB-S4 and present-day optical depth
measurements. These constraints originate both in structure growth probed by
cross-correlation tomography over a wide redshift range as well as, most
importantly, the shape of the galaxy power spectrum measured over a large
volume. We caution that possible complications such as higher-order biasing and
systematic errors in the analysis of high redshift galaxy clustering are only
briefly discussed and may be non-negligible. Nevertheless, our results show
that new kinds of high-precision neutrino mass measurements at and beyond the
present-day optical depth limit may be possible.Comment: 8 pages, 6 figure