The nature of dark matter sets the timeline for the formation of first collapsed haloes and thus affects the sources of reionization. Here, we consider two different models of dark matter: cold dark matter (CDM) and thermal warm dark matter (WDM), and study how they impact the epoch of reionization (EoR) and its 21-cm observables. Using a suite of simulations, we find that in WDM scenarios, the structure formation on small scales gets suppressed, resulting in a smaller number of low-mass dark matter haloes compared to the CDM scenario. Assuming that the efficiency of sources in producing ionizing photons remains the same, this leads to a lower number of total ionizing photons produced at any given cosmic time, thus causing a delay in the reionization process. We also find visual differences in the neutral hydrogen (H I) topology and in 21-cm maps in case of the WDM compared to the CDM. However, differences in the 21-cm power spectra, at the same neutral fraction, are found to be small. Thus, we focus on the non-Gaussianity in the EoR 21-cm signal, quantified through its bispectrum. We find that the 21-cm bispectra (driven by the HI topology) are significantly different in WDM models compared to the CDM, even for the same mass-averaged neutral fractions. This establishes that the 21-cm bispectrum is a unique and promising way to differentiate between dark matter models, and can be used to constrain the nature of the dark matter in the future EoR observations.

Impact of dark matter models on the EoR 21-cm signal bispectrum / Saxena, Anchal; Majumdar, Suman; Kamran, Mohd; Viel, Matteo. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 497:3(2020), pp. 2941-2953. [10.1093/mnras/staa1768]

Impact of dark matter models on the EoR 21-cm signal bispectrum

Matteo Viel
2020-01-01

Abstract

The nature of dark matter sets the timeline for the formation of first collapsed haloes and thus affects the sources of reionization. Here, we consider two different models of dark matter: cold dark matter (CDM) and thermal warm dark matter (WDM), and study how they impact the epoch of reionization (EoR) and its 21-cm observables. Using a suite of simulations, we find that in WDM scenarios, the structure formation on small scales gets suppressed, resulting in a smaller number of low-mass dark matter haloes compared to the CDM scenario. Assuming that the efficiency of sources in producing ionizing photons remains the same, this leads to a lower number of total ionizing photons produced at any given cosmic time, thus causing a delay in the reionization process. We also find visual differences in the neutral hydrogen (H I) topology and in 21-cm maps in case of the WDM compared to the CDM. However, differences in the 21-cm power spectra, at the same neutral fraction, are found to be small. Thus, we focus on the non-Gaussianity in the EoR 21-cm signal, quantified through its bispectrum. We find that the 21-cm bispectra (driven by the HI topology) are significantly different in WDM models compared to the CDM, even for the same mass-averaged neutral fractions. This establishes that the 21-cm bispectrum is a unique and promising way to differentiate between dark matter models, and can be used to constrain the nature of the dark matter in the future EoR observations.
497
3
2941
2953
https://arxiv.org/abs/2004.04808
https://academic.oup.com/mnras/article/497/3/2941/5860290
Saxena, Anchal; Majumdar, Suman; Kamran, Mohd; Viel, Matteo
File in questo prodotto:
File Dimensione Formato  
staa1768.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 4.99 MB
Formato Adobe PDF
4.99 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/114377
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 8
social impact