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Villaescusa-Navarro, F., Vogelsberger, M., Viel, M., & Loeb, A. (2013). Neutrino signatures on the high-transmission regions of the Lyman alpha forest. Mon. Not. Roy. Astron. Soc., 431(4), 3670–3677.
Abstract: We quantify the impact of massive neutrinos on the statistics of low-density regions in the intergalactic medium as probed by the Lyman alpha forest at redshifts z = 2.2-4. Based on mock but realistic quasar (QSO) spectra extracted from hydrodynamic simulations with cold dark matter, baryons and neutrinos, we find that the probability distribution of weak Lyman alpha absorption features, as sampled by Lyman alpha flux regions at high transmissivity, is strongly affected by the presence of massive neutrinos. We show that systematic errors affecting the Lyman alpha forest reduce but do not erase the neutrino signal. Using the Fisher matrix formalism, we conclude that the sum of the neutrino masses can be measured, using the method proposed in this paper, with a precision smaller than 0.4 eV using a catalogue of 200 high-resolution (signal-to-noise ratio similar to 100) QSO spectra. This number reduces to 0.27 eV by making use of reasonable priors in the other parameters that also affect the statistics of the high-transitivity regions of the Lyman alpha forest. The constraints obtained with this method can be combined with independent bounds from the cosmic microwave background, large-scale structures and measurements of the matter power spectrum from the Lyman alpha forest to produce tighter upper limits on the sum of the masses of the neutrinos.
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Anderson, L. et al, de Putter, R., & Mena, O. (2012). The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Data Release 9 spectroscopic galaxy sample. Mon. Not. Roy. Astron. Soc., 427(4), 3435–3467.
Abstract: We present measurements of galaxy clustering from the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey III (SDSS-III). These use the Data Release 9 (DR9) CMASS sample, which contains 264 283 massive galaxies covering 3275 square degrees with an effective redshift z = 0.57 and redshift range 0.43 < z < 0.7. Assuming a concordance Lambda CDM cosmological model, this sample covers an effective volume of 2.2 Gpc(3), and represents the largest sample of the Universe ever surveyed at this density, (n) over bar approximate to 3 x 10(-4) h(-3) Mpc(3). We measure the angle-averaged galaxy correlation function and power spectrum, including density-field reconstruction of the baryon acoustic oscillation (BAO) feature. The acoustic features are detected at a significance of 5 sigma in both the correlation function and power spectrum. Combining with the SDSS-II luminous red galaxy sample, the detection significance increases to 6.7 sigma. Fitting for the position of the acoustic features measures the distance to z = 0.57 relative to the sound horizon D-V/r(s) = 13.67 +/ 0.22 at z = 0.57. Assuming a fiducial sound horizon of 153.19 Mpc, which matches cosmic microwave background constraints, this corresponds to a distance D-V (z = 0.57) = 2094 +/- 34 Mpc. At 1.7 per cent, this is the most precise distance constraint ever obtained from a galaxy survey. We place this result alongside previous BAO measurements in a cosmological distance ladder and find excellent agreement with the current supernova measurements. We use these distance measurements to constrain various cosmological models, finding continuing support for a flat Universe with a cosmological constant.
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Reid, B. A. et al, & de Putter, R. (2012). The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measurements of the growth of structure and expansion rate at z=0.57 from anisotropic clustering. Mon. Not. Roy. Astron. Soc., 426(4), 2719–2737.
Abstract: We analyse the anisotropic clustering of massive galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) sample, which consists of 264-283 galaxies in the redshift range 0.43 < z < 0.7 spanning 3275 deg(2). Both peculiar velocities and errors in the assumed redshiftdistance relation (AlcockPaczynski effect) generate correlations between clustering amplitude and orientation with respect to the line of sight. Together with the sharp baryon acoustic oscillation (BAO) standard ruler, our measurements of the broad-band shape of the monopole and quadrupole correlation functions simultaneously constrain the comoving angular diameter distance (2190 +/- 61 Mpc) to z = 0.57, the Hubble expansion rate at z = 0.57 (92.4 +/- 4.5 km s(-1) Mpc(-1)) and the growth rate of structure at that same redshift (d(sigma 8)/d ln a = 0.43 +/- 0.069). Our analysis provides the best current direct determination of both DA and H in galaxy clustering data using this technique. If we further assume a cold dark matter expansion history, our growth constraint tightens to d(sigma 8)/d ln a = 0.415 +/- 0.034. In combination with the cosmic microwave background, our measurements of D-A,H and d(sigma 8)/d ln a all separately require dark energy at z > 0.57, and when combined imply Omega(A) = 0.74 +/- 0.016, independent of the Universe's evolution at z < 0.57. All of these constraints assume scale-independent linear growth, and assume general relativity to compute both O(10 per cent) non-linear model corrections and our errors. In our companion paper, Samushia et al., we explore further cosmological implications of these observations.
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Vagnozzi, S., Visinelli, L., Mena, O., & Mota, D. F. (2020). Do we have any hope of detecting scattering between dark energy and baryons through cosmology? Mon. Not. Roy. Astron. Soc., 493(1), 1139–1152.
Abstract: We consider the possibility that dark energy and baryons might scatter off each other. The type of interaction we consider leads to a pure momentum exchange, and does not affect the background evolution of the expansion history. We parametrize this interaction in an effective way at the level of Boltzmann equations. We compute the effect of dark energy-baryon scattering on cosmological observables, focusing on the cosmic microwave background (CMB) temperature anisotropy power spectrum and the matter power spectrum. Surprisingly, we find that even huge dark energy-baryon cross-sections sigma(xb) similar to O(b), which are generically excluded by non-cosmological probes such as collider searches or precision gravity tests, only leave an insignificant imprint on the observables considered. In the case of the CMB temperature power spectrum, the only imprint consists in a sub-per cent enhancement or depletion of power (depending whether or not the dark energy equation of state lies above or below -1) at very low multipoles, which is thus swamped by cosmic variance. These effects are explained in terms of differences in how gravitational potentials decay in the presence of a dark energy-baryon scattering, which ultimately lead to an increase or decrease in the late-time integrated Sachs-Wolfe power. Even smaller related effects are imprinted on the matter power spectrum. The imprints on the CMB are not expected to be degenerate with the effects due to altering the dark energy sound speed. We conclude that, while strongly appealing, the prospects for a direct detection of dark energy through cosmology do not seem feasible when considering realistic dark energy-baryon cross-sections. As a caveat, our results hold to linear order in perturbation theory.
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Manera, M., Scoccimarro, R., Percival, W. J., Samushia, L., McBride, C. K., Ross, A. J., et al. (2013). The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: a large sample of mock galaxy catalogues. Mon. Not. Roy. Astron. Soc., 428(2), 1036–1054.
Abstract: We present a fast method for producing mock galaxy catalogues that can be used to compute the covariance of large-scale clustering measurements and test analysis techniques. Our method populates a second-order Lagrangian perturbation theory (2LPT) matter field, where we calibrate masses of dark matter haloes by detailed comparisons with N-body simulations. We demonstrate that the clustering of haloes is recovered at similar to 10 per cent accuracy. We populate haloes with mock galaxies using a halo occupation distribution (HOD) prescription, which has been calibrated to reproduce the clustering measurements on scales between 30 and 80 h(-1) Mpc. We compare the sample covariance matrix from our mocks with analytic estimates, and discuss differences. We have used this method to make catalogues corresponding to Data Release 9 of the Baryon Oscillation Spectroscopic Survey (BOSS), producing 600 mock catalogues of the 'CMASS' galaxy sample. These mocks have enabled detailed tests of methods and errors, and have formed an integral part of companion analyses of these galaxy data.
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