Structures in Warm Dark Matter (WDM) models are exponentially suppressed below a certain scale, characterized by the dark matter particle mass, mx . Since structures form hierarchically, the presence of collapsed objects at high-redshifts can set strong lower limits on mx . We place robust constraints on mx using recent results from the Swift database of high-redshift gamma-ray bursts (GRBs). We parameterize the redshift evolution of the ratio between the cosmic GRB rate and star formation rate (SFR) as ∝ (1+z)α , thereby allowing astrophysical uncertainties to partially mimic the cosmological suppression of structures in WDM models. Using a maximum likelihood estimator on two different z > 4 GRB subsamples (including two bursts at z > 8), we constrain mx 1.6-1.8 keV at 95% CL, when marginalized over a flat prior in α. We further estimate that 5 years of a SVOM-like mission would tighten these constraints to mx 2.3 keV. Our results show that GRBs are a powerful probe of high-redshift structures, providing robust and competitive constraints on mx .

Constraints on warm dark matter models from high-redshift long gamma-ray bursts

MESINGER, ANDREI ALBERT;FERRARA, ANDREA;
2013

Abstract

Structures in Warm Dark Matter (WDM) models are exponentially suppressed below a certain scale, characterized by the dark matter particle mass, mx . Since structures form hierarchically, the presence of collapsed objects at high-redshifts can set strong lower limits on mx . We place robust constraints on mx using recent results from the Swift database of high-redshift gamma-ray bursts (GRBs). We parameterize the redshift evolution of the ratio between the cosmic GRB rate and star formation rate (SFR) as ∝ (1+z)α , thereby allowing astrophysical uncertainties to partially mimic the cosmological suppression of structures in WDM models. Using a maximum likelihood estimator on two different z > 4 GRB subsamples (including two bursts at z > 8), we constrain mx 1.6-1.8 keV at 95% CL, when marginalized over a flat prior in α. We further estimate that 5 years of a SVOM-like mission would tighten these constraints to mx 2.3 keV. Our results show that GRBs are a powerful probe of high-redshift structures, providing robust and competitive constraints on mx .
File in questo prodotto:
File Dimensione Formato  
1303.5060v2.pdf

accesso aperto

Descrizione: postprint full text
Tipologia: Altro materiale allegato
Licenza: Accesso gratuito (sola lettura)
Dimensione 409.3 kB
Formato Adobe PDF
409.3 kB 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: http://hdl.handle.net/11384/24403
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 49
  • ???jsp.display-item.citation.isi??? 49
social impact