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Title: Improved measurements of turbulence in the hot gaseous atmospheres of nearby giant elliptical galaxies

Here, we present significantly improved measurements of turbulent velocities in the hot gaseous haloes of nearby giant elliptical galaxies. Using deep XMM–NewtonReflection Grating Spectrometer ( RGS) observations and a combination of resonance scattering and direct line broadening methods, we obtain well bounded constraints for 13 galaxies. Assuming that the turbulence is isotropic, we obtain a best-fitting mean 1D turbulent velocity of 110 km s -1. This implies a typical 3D Mach number ~0.45 and a typical non-thermal pressure contribution of ~6 per cent in the cores of nearby massive galaxies. The intrinsic scatter around these values is modest – consistent with zero, albeit with large statistical uncertainty – hinting at a common and quasi-continuous mechanism sourcing the velocity structure in these objects. Using conservative estimates of the spatial scales associated with the observed turbulent motions, we find that turbulent heating can be sufficient to offset radiative cooling in the inner regions of these galaxies (<10 kpc, typically 2–3 kpc). The full potential of our analysis methods will be enabled by future X-ray micro-calorimeter observations.
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1] ;  [3] ;  [5] ;  [6]
  1. Stanford Univ., Stanford, CA (United States)
  2. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. Institute of Astronomy, Cambridge (United Kingdom)
  4. MTA-Eotvos Univ. Lendulet Hot Universe Research Group, Budapest (Hungary); Masaryk Univ., Brno (Czech Republic)
  5. SRON Netherlands Institute for Space Research, Utrecht (The Netherlands); Leiden Univ., Leiden (The Netherlands)
  6. SRON Netherlands Institute for Space Research, Utrecht (The Netherlands)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; 340442
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 472; Journal Issue: 2; Journal ID: ISSN 0035-8711
Royal Astronomical Society
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; X-ray: galaxies: clusters; galaxies: clusters: intracluster medium; galaxies: kinematics and dynamics; turbulence; radiative transfer; techniques: spectroscopic
OSTI Identifier: