2014A&A...569A..67G


Query : 2014A&A...569A..67G

2014A&A...569A..67G - Astronomy and Astrophysics, volume 569A, 67-67 (2014/9-1)

The relation between gas density and velocity power spectra in galaxy clusters: High-resolution hydrodynamic simulations and the role of conduction.

GASPARI M., CHURAZOV E., NAGAI D., LAU E.T. and ZHURAVLEVA I.

Abstract (from CDS):

Exploring the power spectrum of fluctuations and velocities in the intracluster medium (ICM) can help us to probe the gas physics of galaxy clusters. Using high-resolution 3D plasma simulations, we study the statistics of the velocity field and its intimate relation with the ICM thermodynamic perturbations. The normalization of the ICM spectrum (related to density, entropy, or pressure fluctuations) is linearly tied to the level of large-scale motions, which excite both gravity and sound waves due to stratification. For a low 3D Mach number M∼0.25, gravity waves mainly drive entropy perturbations, which are traced by preferentially tangential turbulence. For M>0.5, sound waves start to significantly contribute and pass the leading role to compressive pressure fluctuations, which are associated with isotropic (or slightly radial) turbulence. Density and temperature fluctuations are then characterized by the dominant process: isobaric (low M), adiabatic (high M), or isothermal (strong conduction). Most clusters reside in the intermediate regime, showing a mixture of gravity and sound waves, hence drifting toward isotropic velocities. Remarkably, regardless of the regime, the variance of density perturbations is comparable to the 1D Mach number, M1D~δρ/ρ. This linear relation allows us to easily convert between gas motions and ICM perturbations (δρ/ρ<1), which can be exploited by the available Chandra, XMM data and by the forthcoming Astro-H mission. At intermediate and small scales (10-100kpc), the turbulent velocities develop a tight Kolmogorov cascade. The thermodynamic perturbations (which can be generally described by log-normal distributions) act as effective tracers of the velocity field, in broad agreement with the Kolmogorov-Obukhov-Corrsin advection theory. The cluster radial gradients and compressive features induce a flattening in the cascade of the perturbations. Thermal conduction, on the other hand, acts to damp the thermodynamic fluctuations, washing out the filamentary structures and steepening the spectrum, while leaving the velocity cascade unaltered. The ratio of the velocity and density spectrum thus inverts the downtrend shown by the non-diffusive models, as it widens up to ∼5. This new key diagnostic can robustly probe the presence of conductivity in the ICM. We produce X-ray images of the velocity field, showing how future missions (e.g. Astro-H, Athena) can detect velocity dispersions of a few 100km/s (M>0.1 in massive clusters), allowing us to calibrate the linear relation and to constrain relative perturbations down to just a few percent.

Abstract Copyright:

Journal keyword(s): galaxies: clusters: intracluster medium - hydrodynamics - turbulence - conduction - methods: numerical - X-rays: galaxies: clusters

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4551 2

Query : 2014A&A...569A..67G

Basic data :
ACO 1656 -- Cluster of Galaxies
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types:
X (2A,3A,...), ClG (2010A&A,ACO,...), GrG (RASSCALS,[N93]), gLe (2011A&A), C?G (2014A&A), gam (IGR,INTREF), Rad (DB)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) :
12 59 48.7 +27 58 50 [ ] D 2001ApJ...554L.129M
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
FK4 coord. (ep=B1950 eq=1950) :
12 57 24.0 +28 14 59 [ ]
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
Gal coord. (ep=J2000) :
058.0791 +87.9577 [ ]
Syntax of radial velocity (or/and redshift) is : "value [error] (wavelength) quality bibcode"
  • value : radial velocity or/and redshift (Heliocentric frame) according to your Output Options
    (redshift may be not displayed if the data value is <0 and the database inside value is a radial velocity)
  • [error] : error of the corresponding value displayed before
  • (wavelength) : wavelength range of the measurement : Rad, mm, IR, Opt, UV, Xray, Gam or  '∼'(unknown)
  • quality : flag of quality ( A=best quality -> E=worst quality, {� } =unknown quality)
  • bibcode : bibcode of the value's origin
Radial velocity / Redshift / cz :
V(km/s) 6933 [~] / z(spectroscopic) 0.0234 [~] / cz 7015 [~]
   (Opt) C 2016ApJ...819...63R
SIMBAD within arcmin
', {sourceSize:12, color:'#30a090'})); aladin.on('objectClicked', function(object) { var objName=object.data.MAIN_ID; aladin.showPopup(object.ra,object.dec,'',''+ objName+''); });" title="Show Simbad objects"> Overlay Simbad points in this preview
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The search radius has to be specified by the user. It is currently limited to a maximum of 30 arcsec. It depends mostly on the precision or quality of the coordinates (SIMBAD and VizieR catalogs), the resolution of the images from which the sources were extracted, source extent, and source crowding.
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Hierarchy : number of linked objects
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: 2798
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Identifiers (44) :
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ACO 1656 EXSS 1257.4+2815 NAME Coma Cluster 2U 1257+28
2A 1257+283 FR 76 PBC J1259.5+2756 3U 1257+28
3A 1257+282 1H 1257+281 PLCKESZ G057.33+88.01 4U 1257+28
BAX 194.9531+27.9807 H 1257+283 PSZ1 G057.84+87.98 XSS J12596+2759
CAN 90 H 1256+27 PSZ2 G057.80+88.00 X Com X-1
CID 90 HMS 1257+2814 RASSCALS NRGb226 [F81] 253
ClG 1257.4+2815 IGR J12595+2755 RBS 1198 [KRL2007b] 128
DB 88 INTREF 534 RXC J1259.7+2756 [KVC2005] 8
2E 2932 1M 1257+281 RX J1259.7+2756 [N93] 109
2E 1257.4+2812 2MAXI J1259+279 1RXS J125947.9+275636 [S85] 222
1ES 1257+28.2 MCXC J1259.7+2756 SWIFT J1259.7+2755 [SPD2011] 67

References (4551 between 1850 and 2022) (Total 4551)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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Collections of Measurements


velocities : 7   

   

Observing logs


herschel : 4    XMM : 18   

   


External archives :

Archive data at HEASARC - High-Energy Astrophysics Science Archive Research Center

Data at NED - NASA/IPAC Extragalactic Database : ACO 1656

Link by name to the catalogue in VizieR :

ACO 1656 2E 2932 RXC J1259.7+2756 1RXS J125947.9+275636

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2022.10.01-14:00:13

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