We investigate the impact that warm dark matter (WDM) has in terms of 21 cm intensity mapping in the post-reionization Universe at z=3‑5. We perform hydrodynamic simulations for 5 different models: cold dark matter and WDM with 1,2,3,4 keV (thermal relic) mass and assign the neutral hydrogen a-posteriori using two different methods that both reproduce observations in terms of column density distribution function of neutral hydrogen systems. Contrary to naive expectations, the suppression of power present in the linear and non-linear matter power spectra, results in an increase of power in terms of neutral hydrogen and 21 cm power spectra. This is due to the fact that there is a lack of small mass halos in WDM models with respect to cold dark matter: in order to distribute a total amount of neutral hydrogen within the two cosmological models, a larger quantity has to be placed in the most massive halos, that are more biased compared to the cold dark matter cosmology. We quantify this effect and address significance for the telescope SKA1-LOW, including a realistic noise modeling. The results indicate that we will be able to rule out a 4 keV WDM model with 5000 hours of observations at z>3, with a statistical significance of >3 σ, while a smaller mass of 3 keV, comparable to present day constraints, can be ruled out at more than 2 σ confidence level with 1000 hours of observations at z>5.

Warm dark matter signatures on the 21cm power spectrum: intensity mapping forecasts for SKA

Viel, Matteo;Lapi, Andrea
2015-01-01

Abstract

We investigate the impact that warm dark matter (WDM) has in terms of 21 cm intensity mapping in the post-reionization Universe at z=3‑5. We perform hydrodynamic simulations for 5 different models: cold dark matter and WDM with 1,2,3,4 keV (thermal relic) mass and assign the neutral hydrogen a-posteriori using two different methods that both reproduce observations in terms of column density distribution function of neutral hydrogen systems. Contrary to naive expectations, the suppression of power present in the linear and non-linear matter power spectra, results in an increase of power in terms of neutral hydrogen and 21 cm power spectra. This is due to the fact that there is a lack of small mass halos in WDM models with respect to cold dark matter: in order to distribute a total amount of neutral hydrogen within the two cosmological models, a larger quantity has to be placed in the most massive halos, that are more biased compared to the cold dark matter cosmology. We quantify this effect and address significance for the telescope SKA1-LOW, including a realistic noise modeling. The results indicate that we will be able to rule out a 4 keV WDM model with 5000 hours of observations at z>3, with a statistical significance of >3 σ, while a smaller mass of 3 keV, comparable to present day constraints, can be ruled out at more than 2 σ confidence level with 1000 hours of observations at z>5.
2015
2015
7
47
047
https://arxiv.org/abs/1502.06961
Carucci, I. P; Villaescusa Navarro, F; Viel, Matteo; Lapi, Andrea
File in questo prodotto:
File Dimensione Formato  
Carucci15.pdf

non disponibili

Licenza: Non specificato
Dimensione 7.32 MB
Formato Adobe PDF
7.32 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

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/20.500.11767/12539
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 45
  • ???jsp.display-item.citation.isi??? 48
social impact