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Probing dark energy and neutrino mass from upcoming lensing experiments of CMB and galaxies  [PDF]
Toshiya Namikawa,Shun Saito,Atsushi Taruya
Physics , 2010, DOI: 10.1088/1475-7516/2010/12/027
Abstract: We discuss the synergy of the cosmic shear and CMB lensing experiments to simultaneously constrain the neutrino mass and dark energy properties. Taking fully account of the CMB lensing, cosmic shear, CMB anisotropies, and their cross correlation signals, we clarify a role of each signal, and investigate the extent to which the upcoming observations by a high-angular resolution experiment of CMB and deep galaxy imaging survey can tightly constrain the neutrino mass and dark energy equation-of-state parameters. Including the primary CMB information as a prior cosmological information, the Fisher analysis reveals that the time varying equation-of-state parameters, given by w(a)=w_0+w_a(1-a), can be tightly constrained with the accuracies of 5% for w_0 and 15% for w_a, which are comparable to or even better than those of the stage-III type surveys neglecting the effect of massive neutrinos. In other words, including the neutrino mass in the parameter estimation would not drastically alter the Figure-of-Merit estimates of dark energy parameters from the weak lensing measurements. For the neutrino mass, a clear signal for total neutrino mass with 0.1 eV can be detected with 2-sigma significance. The robustness and sensitivity of these results are checked in detail by allowing the setup of cosmic shear experiment to vary as a function of observation time or exposure time, showing that the improvement of the constraints very weakly depends on the survey parameters, and the results mentioned above are nearly optimal for the dark energy parameters and the neutrino mass.
CMB Lensing Constraints on Neutrinos and Dark Energy  [PDF]
Roland de Putter,Oliver Zahn,Eric V. Linder
Physics , 2009, DOI: 10.1103/PhysRevD.79.065033
Abstract: Signatures of lensing of the cosmic microwave background radiation by gravitational potentials along the line of sight carry with them information on the matter distribution, neutrino masses, and dark energy properties. We examine the constraints that Planck, PolarBear, and CMBpol future data, including from the B-mode polarization or the lensing potential, will be able to place on these quantities. We simultaneously fit for neutrino mass and dark energy equation of state including time variation and early dark energy density, and compare the use of polarization power spectra with an optimal quadratic estimator of the lensing. Results are given as a function of systematics level from residual foreground contamination. A realistic CMBpol experiment can effectively constrain the sum of neutrino masses to within 0.05 eV and the fraction of early dark energy to 0.002. We also present a surprisingly simple prescription for calculating dark energy equation of state constraints in combination with supernova distances from JDEM.
Neutrinos and dark energy constraints from future galaxy surveys and CMB lensing information  [PDF]
Larissa Santos,Paolo Cabella,Amedeo Balbi,Nicola Vittorio
Physics , 2013, DOI: 10.1103/PhysRevD.88.043505
Abstract: We explore the possibility of obtaining better constraints from future astronomical data by means of the Fisher information matrix formalism. In particular, we consider how cosmic microwave background (CMB) lensing information can improve our parameter error estimation. We consider a massive neutrino scenario and a time-evolving dark energy equation of state in the $\Lambda$CDM framework. We use Planck satellite experimental specifications together with the future galaxy survey Euclid in our forecast. We found improvements in almost all studied parameters considering Planck alone when CMB lensing information is used. In this case, the improvement with respect to the constraints found without using CMB lensing is of 93% around the fiducial value for the neutrino parameter. The improvement on one of the dark energy parameter reaches 4.4%. When Euclid information is included in the analysis, the improvements on the neutrino parameter constraint is of approximately 128% around its fiducial value. The addition of Euclid information provides smaller errors on the dark energy parameters as well. For Euclid alone, the FoM is a factor of $\sim$ 29 higher than that from Planck alone even considering CMB lensing. Finally, the consideration of a nearly perfect CMB experiment showed that CMB lensing cannot be neglected specially in more precise future CMB experiments since it provided in our case a 6 times better FoM in respect to the unlensed CMB analysis .
Ultra-light Axions: Degeneracies with Massive Neutrinos and Forecasts for Future Cosmological Observations  [PDF]
David J. E. Marsh,Edward Macaulay,Maxime Trebitsch,Pedro G. Ferreira
Physics , 2011, DOI: 10.1103/PhysRevD.85.103514
Abstract: A generic prediction of string theory is the existence of many axion fields. It has recently been argued that many of these fields should be light and, like the well known QCD axion, lead to observable cosmological consequences. In this paper we study in detail the effect of the so-called string axiverse on large scale structure, focusing on the morphology and evolution of density perturbations, anisotropies in the cosmic microwave background and weak gravitational lensing of distant galaxies. We quantify specific effects that will arise from the presence of the axionic fields and highlight possible degeneracies that may arise in the presence of massive neutrinos. We take particular care understanding the different physical effects and scales that come into play. We then forecast how the string axiverse may be constrained and show that with a combination of different observations, it should be possible to detect a fraction of ultralight axions to dark matter of a few percent.
Weak lensing forecasts for dark energy, neutrinos and initial conditions  [PDF]
Ivan Debono,Anais Rassat,Alexandre Refregier,Adam Amara,Thomas D. Kitching
Physics , 2009, DOI: 10.1111/j.1365-2966.2010.16284.x
Abstract: Weak gravitational lensing provides a sensitive probe of cosmology by measuring the mass distribution and the geometry of the low redshift universe. We show how an all-sky weak lensing tomographic survey can jointly constrain different sets of cosmological parameters describing dark energy, massive neutrinos (hot dark matter), and the primordial power spectrum. In order to put all sectors on an equal footing, we introduce a new parameter $\beta$, the second order running spectral index. Using the Fisher matrix formalism with and without CMB priors, we examine how the constraints vary as the parameter set is enlarged. We find that weak lensing with CMB priors provides robust constraints on dark energy parameters and can simultaneously provide strong constraints on all three sectors. We find that the dark energy sector is largely insensitive to the inclusion of the other cosmological sectors. Implications for the planning of future surveys are discussed.
$ν$Galileon: modified gravity with massive neutrinos as a testable alternative to $Λ$CDM  [PDF]
Alexandre Barreira,Baojiu Li,Carlton Baugh,Silvia Pascoli
Physics , 2014, DOI: 10.1103/PhysRevD.90.023528
Abstract: We show that, in the presence of massive neutrinos, the Galileon gravity model provides a very good fit to the current CMB temperature, CMB lensing and BAO data. This model, which we dub ${\nu} \rm{Galileon}$, when assuming its stable attractor background solution, contains the same set of free parameters as $\Lambda\rm{CDM}$, although it leads to different expansion dynamics and nontrivial gravitational interactions. The data provide compelling evidence ($\gtrsim 6\sigma$) for nonzero neutrino masses, with $\Sigma m_\nu \gtrsim 0.4\ {\rm eV}$ at the $2\sigma$ level. Upcoming precision terrestrial measurements of the absolute neutrino mass scale therefore have the potential to test this model. We show that CMB lensing measurements at multipoles $l \lesssim 40$ will be able to discriminate between the ${\nu} \rm{Galileon}$ and $\Lambda\rm{CDM}$ models. Unlike $\Lambda\rm{CDM}$, the ${\nu} \rm{Galileon}$ model is consistent with local determinations of the Hubble parameter. The presence of massive neutrinos lowers the value of $\sigma_8$ substantially, despite of the enhanced gravitational strength on large scales. Unlike $\Lambda\rm{CDM}$, the ${\nu} \rm{Galileon}$ model predicts a negative ISW effect, which is difficult to reconcile with current observational limits.
Cosmological Implications of Massive Neutrinos  [PDF]
L. A. Popa
Physics , 2002,
Abstract: The massive neutrinos gravitational infall and their inprints left on the CMB temperature and matter density fluctuations power spectra are analysed taking into account the massive neutrino properties: the mass degeneracy, the phase space mixing, the lepton asymmetry.
Measuring cluster masses with CMB lensing: a statistical approach  [PDF]
Jean-Baptiste Melin,James G. Bartlett
Physics , 2014, DOI: 10.1051/0004-6361/201424720
Abstract: We present a method for measuring the masses of galaxy clusters using the imprint of their gravitational lensing signal on the cosmic microwave background (CMB) temperature anisotropies. The method first reconstructs the projected gravitational potential with a quadratic estimator and then applies a matched filter to extract cluster mass. The approach is well-suited for statistical analyses that bin clusters according to other mass proxies. We find that current experiments, such as Planck, the South Pole Telescope and the Atacama Cosmology Telescope, can practically implement such a statistical methodology, and that future experiments will reach sensitivities sufficient for individual measurements of massive systems. As illustration, we use simulations of Planck observations to demonstrate that it is possible to constrain the mass scale of a set of 62 massive clusters with prior information from X-ray observations, similar to the published Planck ESZ-XMM sample. We examine the effect of the thermal (tSZ) and kinetic (kSZ) Sunyaev-Zeldovich (SZ) signals, finding that the impact of the kSZ remains small in this context. The stronger tSZ signal, however, must be actively removed from the CMB maps by component separation techniques prior to reconstruction of the gravitational potential. Our study of two such methods highlights the importance of broad frequency coverage for this purpose. A companion paper presents application to the Planck data on the ESZ-XMM sample.
CMB Lensing - Power Without Bias  [PDF]
Blake D. Sherwin,Sudeep Das
Physics , 2010,
Abstract: We propose a novel bias-free method for reconstructing the power spectrum of the weak lensing deflection field from cosmic microwave background (CMB) observations. The proposed method is in contrast to the standard method of CMB lensing reconstruction where a reconstruction bias needs to be subtracted to estimate the lensing power spectrum. This bias depends very sensitively on the modeling of the signal and noise properties of the survey, and a misestimate can lead to significantly inaccurate results. Our method obviates this bias and hence the need to characterize the detailed noise properties of the CMB experiment. We illustrate our method with simulated lensed CMB maps with realistic noise distributions. This bias-free method can also be extended to create much more reliable estimators for other four-point functions in cosmology, such as those appearing in primordial non-Gaussianity estimators.
(Lack of) Cosmological evidence for dark radiation after Planck  [PDF]
Licia Verde,Stephen M. Feeney,Daniel J. Mortlock,Hiranya V. Peiris
Physics , 2013, DOI: 10.1088/1475-7516/2013/09/013
Abstract: We use Bayesian model comparison to determine whether extensions to Standard-Model neutrino physics -- primarily additional effective numbers of neutrinos and/or massive neutrinos -- are merited by the latest cosmological data. Given the significant advances in cosmic microwave background (CMB) observations represented by the Planck data, we examine whether Planck temperature and CMB lensing data, in combination with lower redshift data, have strengthened (or weakened) the previous findings. We conclude that the state-of-the-art cosmological data do not show evidence for deviations from the standard cosmological model (which has three massless neutrino families). This does not mean that the model is necessarily correct -- in fact we know it is incomplete as neutrinos are not massless -- but it does imply that deviations from the standard model (e.g., non-zero neutrino mass) are too small compared to the current experimental uncertainties to be inferred from cosmological data alone.
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