Probing small scale primordial power spectrum with 21cm line global signal

Yoshiura, Shintaro; Takahashi, Keitaro; Takahashi, Tomo

doi:10.1103/physrevd.101.083520

Cited by 14 publications

(12 citation statements)

References 65 publications

(83 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By detecting 21-cm absorption, the EDGES result demands x α 1 at z = 20, where the absorption signal starts. We note that, in addition, the non-detection of signal for z > 20 implies an upper bound on x α , and thus on the power spectrum [41], although we will not attempt to find this value here.…”

Section: E Edges Datamentioning

confidence: 99%

See 1 more Smart Citation

Probing the small-scale matter power spectrum with large-scale 21-cm data

2020

View full text Add to dashboard Cite

The distribution of matter fluctuations in our universe is key for understanding the nature of dark matter and the physics of the early cosmos. Different observables have been able to map this distribution at large scales, corresponding to wavenumbers k 10 Mpc −1 , but smaller scales remain much less constrained. In this work we study the sensitivity of upcoming measurements of the 21-cm line of neutral hydrogen to the small-scale matter power spectrum. The 21-cm line is a promising tracer of early stellar formation, which took place in small haloes (with masses M ∼ 10 6 − 10 8 M ), formed out of matter overdensities with wavenumbers as large as k ≈ 100 Mpc −1 . Here we forecast how well both the 21-cm global signal, and its fluctuations, could probe the matter power spectrum during cosmic dawn (z = 12−25). In both cases we find that the long-wavelength modes (with k 40 Mpc −1 ) are highly degenerate with astrophysical parameters, whereas the modes with k = (40 − 80) Mpc −1 are more readily observable. This is further illustrated in terms of the principal components of the matter power spectrum, which peak at k ∼ 50 Mpc −1 both for a typical experiment measuring the 21-cm global signal and its fluctuations. We find that, imposing broad priors on astrophysical parameters, a global-signal experiment can measure the amplitude of the matter power spectrum integrated over k = (40−80) Mpc −1 with a precision of tens of percent. A fluctuation experiment, on the other hand, can constrain the power spectrum to a similar accuracy over both the k = (40 − 60) Mpc −1 and (60 − 80) Mpc −1 ranges even without astrophysical priors. The constraints outlined in this work would be able to test the behavior of dark matter at the smallest scales yet measured, for instance probing warm-dark matter masses up to mWDM = 8 keV for the global signal and 14 keV for the 21-cm fluctuations. This could shed light on the nature of dark matter beyond the reach of other cosmic probes.

show abstract

Section: E Edges Datamentioning

confidence: 99%

“…First, running the 21-cm simulations required to constrain each DM model can be costly, so a model-agnostic approach is preferred. Second, we want to search for any deviation from the standard CDM scenario, regardless of its origin, which includes both darkmatter physics as well as non-standard inflationary scenarios [40,41].…”

Section: Introductionmentioning

confidence: 99%

Probing the small-scale matter power spectrum with large-scale 21-cm data

2020

View full text Add to dashboard Cite

show abstract

“…In fact, the majority of the WDM constraints cited concern small-scale structure in the local Universe (z 6). Moreover, as WDM is primarily a theory about the abundance and turnover of small-mass halos, there is perhaps nowhere its effects will be as readily apparent and testable as within the high redshift Universe, particularly the Cosmic Dawn and Epoch of Reionization (Sitwell et al 2014;Lopez-Honorez et al 2017;Schneider 2018;Lopez-Honorez et al 2019;Muñoz & Loeb 2018;Yoshiura et al 2020). Thus, an analysis of the effects of WDM upon the global 21-cm signal (henceforth, global signal) allows for the possibility of WDM mass constraints in epochs in which such measurements have never been performed and which entertain exquisite sensitivity to small-scale structure.…”

Section: Introductionmentioning

confidence: 99%

Constraining Warm Dark Matter and Pop III stars with the Global 21-cm Signal

Hibbard,

Mirocha,

Rapetti

et al. 2022

Preprint

View full text Add to dashboard Cite

Upcoming ground and space-based experiments may have sufficient accuracy to place significant constraints upon high-redshift star formation, Reionization, and dark matter (DM) using the global 21-cm signal of the IGM. In the early universe, when the relative abundance of low-mass DM halos is important, measuring the global signal would place constraints on the damping of structure formation caused by DM having a higher relic velocity (warm dark matter, or WDM) than in cold dark matter (CDM). Such damping, however, can be mimicked by altering the star formation efficiency (SFE) and difficult to detect because of the presence of Pop III stars with unknown properties. We study these various cases and their degeneracies with the WDM mass parameter m X using a Fisher matrix analysis. We study the m X = 7 keV case and a star-formation model that parametrizes the SFE as a strong function of halo mass and include several variations of this model along with three different input noise levels for the likelihood. We find that when the likelihood includes only Pop II stars, m X is constrained to ∼ 0.4 keV for all models and noise levels at 68% CI. When the likelihood includes weak Pop III stars, m X ∼ 0.3 keV, and if Pop III star formation is relatively efficient, m X ∼ 0.1 keV, with tight Pop III star-formation parameter constraints. Our results show that the global 21-cm signal is a promising test-bed for WDM models, even in the presence of strong degeneracies with astrophysical parameters.

show abstract

“…In general, any model which suppresses or modifies the amplitude of DM fluctuations on small scales could affect the 21-cm cosmic dawn signal (see e.g., Refs. [54][55][56][57][58][59][60][61][62]). Exploring the 21-cm signal from this broad parameter space of possible DM models can be quite costly since it generally requires detailed simulations.…”

Section: Introductionmentioning

confidence: 99%

ETHOS ‐ an effective theory of structure formation: Impact of dark acoustic oscillations on cosmic dawn

et al. 2021

View full text Add to dashboard Cite

Upcoming data of the 21-cm hydrogen line during cosmic dawn (z ∼ 10-30) will revolutionize our understanding of the astrophysics of the first galaxies. Here we present a case study on how to exploit those same measurements to learn about the nature of dark matter (DM) at small scales. Focusing on the effective theory of structure formation (ETHOS) paradigm, we run a suite of simulations covering a broad range of DM microphysics, connecting the output of N-body simulations to dedicated 21-cm simulations to predict the evolution of the 21-cm signal across the entire cosmic dawn. We find that observatories targeting both the global signal and the 21-cm power spectrum are sensitive to all ETHOS models we study, and can distinguish them from CDM if the suppression wave number is smaller than k ≈ 300 h=Mpc, even when accounting for feedback with a phenomenological model. This is an order of magnitude smaller comoving scales than currently constrained by other datasets, including the Lyman-α forest. Moreover, if a prospective 21-cm detection confirmed a deficiency of power at small scales, we show that ETHOS models with strong dark acoustic oscillations can be discriminated from the pure suppression of warm dark matter, showing the power of 21-cm data to understand the behavior of DM at the smallest physical scales.

show abstract

Probing small scale primordial power spectrum with 21cm line global signal

Cited by 14 publications

References 65 publications

Probing the small-scale matter power spectrum with large-scale 21-cm data

Probing the small-scale matter power spectrum with large-scale 21-cm data

Constraining Warm Dark Matter and Pop III stars with the Global 21-cm Signal

ETHOS ‐ an effective theory of structure formation: Impact of dark acoustic oscillations on cosmic dawn

Contact Info

Product

Resources

About