Eliminating the optical depth nuisance from the CMB with 21 cm cosmology

Liu, Adrian; Pritchard, Jonathan R.; Allison, Rupert; Parsons, Aaron; Seljak, Uroš; Sherwin, Blake D.

doi:10.1103/physrevd.93.043013

Cited by 123 publications

(138 citation statements)

References 125 publications

(189 reference statements)

Supporting

Mentioning

131

Contrasting

Unclassified

Order By: Relevance

“…Ongoing and future experiments like LOFAR, MWA, and SKA, aimed at measuring the redshifted 21-cm signal from neutral hydrogen during the EoR, should be able to probe reionization directly and measure its redshift and duration to high accuracy. Moreover, since reionization appears to happen at redshifts below 10, experiments measuring the global emission of the 21-m line over the sky (e.g., EDGES; Bowman & Rogers 2010, LEDA;Greenhill & Bernardi 2012, DARE;Burns et al 2012, NenuFAR;Zarka et al 2012, SARAS;Patra et al 2013, SCI-HI;Voytek et al 2014, ZEBRA;Mahesh et al 2014, andBIGHORNS, Sokolowski et al 2015) will also be able to derive very competitive constraints on the models (e.g., Liu et al 2016;Fialkov & Loeb 2016 lollipop, the LOw-LIkelihood on POlarized Power-spectra, is a likelihood function based on cross-power spectra for the low multipoles. The idea behind this approach is that the noise can be considered as uncorrelated between maps and that systematics will be considerably reduced in cross-correlation compared to auto-correlation.…”

Section: Modelmentioning

confidence: 99%

“…In practice, the CMB is sensitive to the average over all sky directions of x e (1 + δ b ) (where δ b denotes the baryon overdensity). The IGM is likely to be very inhomogeneous during reionization process, with ionized bubbles embedded in neutral surroundings, which would impact the relation between the optical depth and the reionisation parameters (see Liu et al 2016) at a level which is neglected in this paper.…”

Section: Parametrization Of Reionization Historymentioning

confidence: 99%

See 1 more Smart Citation

Planckintermediate results

Adam

Aghanim

Ashdown

et al. 2016

A&A

406

View full text Add to dashboard Cite

We investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058±0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric or an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z = 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of ∆z < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. We show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.

show abstract

Section: Modelmentioning

confidence: 99%

Section: Parametrization Of Reionization Historymentioning

confidence: 99%

Planckintermediate results

Adam

Aghanim

Ashdown

et al. 2016

A&A

406

View full text Add to dashboard Cite

show abstract

“…We note that 21-cm experiments, which map the brightness temperature of neutral hydrogen as a function of redshift, will probe the epoch of reionization [67]; the combination of this information with CMB þ BAO would break the Σm ν − τ degeneracy and improve the neutrino mass constraint (investigated in Liu et al [68]). …”

Section: A Importance Of the Reionization Bumpmentioning

confidence: 99%

Towards a cosmological neutrino mass detection

et al. 2015

View full text Add to dashboard Cite

Future cosmological measurements should enable the sum of neutrino masses to be determined indirectly through their effects on the expansion rate of the Universe and the clustering of matter. We consider prospects for the gravitationally lensed cosmic microwave background (CMB) anisotropies and baryon acoustic oscillations (BAOs) in the galaxy distribution, examining how the projected uncertainty of ≈15 meV on the neutrino mass sum (a 4σ detection of the minimal mass) might be reached over the next decade. The current 1σ uncertainty of ≈103 meV (Planck-2015 þ BAO-15) will be improved by upcoming "Stage-3" (S3) CMB experiments (S3 þ BAO-15∶ 44 meV), then upcoming BAO measurements (S3 þ DESI∶ 22 meV), and planned next-generation "Stage 4" (S4) CMB experiments (S4 þ DESI∶ 15-19 meV, depending on angular range). An improved optical depth measurement is important: the projected neutrino mass uncertainty increases to 26 meV if S4 is limited to l > 20 and combined with current large-scale polarization data. Looking beyond ΛCDM, including curvature uncertainty increases the forecast mass error by ≈50% for S4 þ DESI, and more than doubles the error with a two-parameter dark-energy equation of state. Complementary low-redshift probes including galaxy lensing will play a role in distinguishing between massive neutrinos and a departure from a w ¼ −1, flat geometry.

show abstract

“…The optical depth could be measured to the cosmic variance limit (CVL) by a future space-based CMB experiment or by a ground-based CMB experiment if significant advances are made in controlling low-polarization systematics. It could also be potentially improved beyond CVL with a 21 cm experiment [40].…”

Section: Discussionmentioning

confidence: 99%

Fundamental physics from future weak-lensing calibrated Sunyaev-Zel’dovich galaxy cluster counts

2017

View full text Add to dashboard Cite

Future high-resolution measurements of the cosmic microwave background (CMB) will produce catalogs of tens of thousands of galaxy clusters through the thermal Sunyaev-Zel'dovich (tSZ) effect. We forecast how well different configurations of a CMB Stage-4 experiment can constrain cosmological parameters, in particular the amplitude of structure as a function of redshift σ8(z), the sum of neutrino masses Σmν , and the dark energy equation of state w(z). A key element of this effort is calibrating the tSZ scaling relation by measuring the lensing signal around clusters. We examine how the mass calibration from future optical surveys like the Large Synoptic Survey (LSST) compares with a purely internal calibration using lensing of the CMB itself. We find that, due to its high-redshift leverage, internal calibration gives constraints on cosmological parameters comparable to the optical calibration, and can be used as a cross-check of systematics in the optical measurement. We also show that in contrast to the constraints using the CMB lensing power spectrum, lensing-calibrated tSZ cluster counts can detect a minimal Σmν at the 3-5σ level even when the dark energy equation of state is freed up.

show abstract

Eliminating the optical depth nuisance from the CMB with 21 cm cosmology

Cited by 123 publications

References 125 publications

Planckintermediate results

Planckintermediate results

Towards a cosmological neutrino mass detection

Fundamental physics from future weak-lensing calibrated Sunyaev-Zel’dovich galaxy cluster counts

Contact Info

Product

Resources

About