The total mass derived from X-ray emission is biased low in a large number of clusters when compared with the mass estimated via strong and weak lensing. Suzaku and Chandra observations out to the virial radius report in several relaxed clusters steep temperature gradients that on assuming pure thermal hydrostatic equilibrium imply an unphysically decreasing mass profile. Moreover, the gas mass fraction appears to be inconsistent with the cosmic value measured from the CMB. Such findings can be interpreted as an evidence for an additional nonthermal pressure in the outskirts of these clusters. This nonthermal component may be due to turbulence stirred by residual bulk motions of extragalactic gas infalling into the cluster. Here we present a SuperModel analysis of Abell 1835 observed by Chandra out to the virial radius. The SuperModel formalism can include in the equilibrium a nonthermal component whose level and distribution are derived imposing that the gas mass fraction fgas equals the cosmic value at the virial radius. Including such a nonthermal component, we reconstruct from X rays an increasing mass profile consistent with the hydrostatic equilibrium also in the cluster outskirts and in agreement at the virial boundary with the weak lensing value. The increasing fgas profile confirms that the baryons are not missing but located at the cluster outskirts.

Turbulence in the SuperModel: Mass Reconstruction with Nonthermal Pressure for Abell 1835 / Fusco Femiano, R; Lapi, Andrea. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - 771:2(2013), pp. 102.1-102.7. [10.1088/0004-637X/771/2/102]

Turbulence in the SuperModel: Mass Reconstruction with Nonthermal Pressure for Abell 1835

Lapi, Andrea
2013-01-01

Abstract

The total mass derived from X-ray emission is biased low in a large number of clusters when compared with the mass estimated via strong and weak lensing. Suzaku and Chandra observations out to the virial radius report in several relaxed clusters steep temperature gradients that on assuming pure thermal hydrostatic equilibrium imply an unphysically decreasing mass profile. Moreover, the gas mass fraction appears to be inconsistent with the cosmic value measured from the CMB. Such findings can be interpreted as an evidence for an additional nonthermal pressure in the outskirts of these clusters. This nonthermal component may be due to turbulence stirred by residual bulk motions of extragalactic gas infalling into the cluster. Here we present a SuperModel analysis of Abell 1835 observed by Chandra out to the virial radius. The SuperModel formalism can include in the equilibrium a nonthermal component whose level and distribution are derived imposing that the gas mass fraction fgas equals the cosmic value at the virial radius. Including such a nonthermal component, we reconstruct from X rays an increasing mass profile consistent with the hydrostatic equilibrium also in the cluster outskirts and in agreement at the virial boundary with the weak lensing value. The increasing fgas profile confirms that the baryons are not missing but located at the cluster outskirts.
2013
771
2
1
7
102
10.1088/0004-637X/771/2/102
Fusco Femiano, R; Lapi, Andrea
File in questo prodotto:
File Dimensione Formato  
FuscoFemiano13b.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Non specificato
Dimensione 353.01 kB
Formato Adobe PDF
353.01 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: https://hdl.handle.net/20.500.11767/12790
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 12
  • ???jsp.display-item.citation.isi??? 10
social impact