We submit that nonthermalized support for the outer intracluster medium in relaxed galaxy clusters is provided by turbulence, which is driven by inflows of intergalactic gas across the virial accretion shocks. We expect this component to increase briskly during the cluster development for z ⪉ 1/2, owing to three factors. First, the accretion rates of gas and dark matter subside when they feed on the outer wings of the initial perturbations in the accelerating Universe. Second, the infall speeds decrease across the progressively shallower gravitational potential at the shock position. Third, the shocks eventually weaken and leave less thermal energy to feed the intracluster entropy, but relatively more bulk energy to drive turbulence into the outskirts. The overall outcome from these factors is physically modeled and analytically computed; thus we ascertain how these concur in setting the equilibrium of the outer intracluster medium, and predict how the observables in X-rays and μwaves are affected, so as to probe the development of outer turbulence over wide cluster samples. By the same token, we quantify the resulting negative bias to be expected in the total mass evaluated from X-ray measurements.

Nonthermal Support for the Outer Intracluster Medium / Cavaliere, A.; Lapi, A.; Fusco-Femiano, R.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 525:(2011), pp. A110.1-A110.7. [10.1051/0004-6361/201015390]

Nonthermal Support for the Outer Intracluster Medium

Lapi, A.;
2011-01-01

Abstract

We submit that nonthermalized support for the outer intracluster medium in relaxed galaxy clusters is provided by turbulence, which is driven by inflows of intergalactic gas across the virial accretion shocks. We expect this component to increase briskly during the cluster development for z ⪉ 1/2, owing to three factors. First, the accretion rates of gas and dark matter subside when they feed on the outer wings of the initial perturbations in the accelerating Universe. Second, the infall speeds decrease across the progressively shallower gravitational potential at the shock position. Third, the shocks eventually weaken and leave less thermal energy to feed the intracluster entropy, but relatively more bulk energy to drive turbulence into the outskirts. The overall outcome from these factors is physically modeled and analytically computed; thus we ascertain how these concur in setting the equilibrium of the outer intracluster medium, and predict how the observables in X-rays and μwaves are affected, so as to probe the development of outer turbulence over wide cluster samples. By the same token, we quantify the resulting negative bias to be expected in the total mass evaluated from X-ray measurements.
2011
525
1
7
A110
https://doi.org/10.1051/0004-6361/201015390
https://arxiv.org/abs/1010.4415
Cavaliere, A.; Lapi, A.; Fusco-Femiano, R.
File in questo prodotto:
File Dimensione Formato  
Cavaliere11a.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Non specificato
Dimensione 258.34 kB
Formato Adobe PDF
258.34 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/20.500.11767/15921
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 6
  • ???jsp.display-item.citation.isi??? 22
social impact