Gas sloshing, cold front formation and metal redistribution: the Virgo cluster as a quantitative test case

Röediger, E.; Brüggen, M.; Simionescu, A.; Böhringer, H.; Churazov, E.; Forman, W.

doi:10.1111/j.1365-2966.2011.18279.x

Cited by 142 publications

(213 citation statements)

References 58 publications

(103 reference statements)

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“…Non-viscous hydrodynamical simulations of cold fronts in the ICM commonly show the development of these instabilities (e.g. Murray et al 1993;Heinz et al 2003;ZuHone, Markevitch & Johnson 2010;Roediger et al 2011) and . Chandra exposure-corrected image smoothed with a 2D Gaussian σ = 6 arcsec showing a 2 arcmin × 2 arcmin region around the NE group core (upper left).…”

Section: Imaging Analysismentioning

confidence: 99%

“…Observations of Kelvin-Helmholtz instabilities along cold fronts, or their absence, can provide a measure of the gas viscosity and magnetic field strength in the intracluster medium (ICM; e.g. Vikhlinin, Markevitch & Murray 2001b;Roediger et al 2011;ZuHone, Markevitch & Lee 2011). The sharp temperature and density changes across cold fronts also suggests that thermal conduction and diffusion are strongly suppressed (e.g.…”

mentioning

confidence: 99%

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The bow shock, cold fronts and disintegrating cool core in the merging galaxy group RX J0751.3+5012

Russell¹,

Fabian²,

McNamara³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Section: Imaging Analysismentioning

confidence: 99%

mentioning

confidence: 99%

The bow shock, cold fronts and disintegrating cool core in the merging galaxy group RX J0751.3+5012

Russell¹,

Fabian²,

McNamara³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…A potential problem with this interpretation is the fact that numerical simulations, like e.g. Ascasibar & Markevitch (2006) and Roediger et al (2011) show that for a sloshing cluster the velocity field in the centre of the hot gas has a much smaller amplitude than the velocities in the outskirts. Since we are probing mainly the inner ∼10 kpc of the galaxy, we should not see the high velocities associated with the merger.…”

Section: Origin Of Turbulencementioning

confidence: 99%

Estimating turbulent velocities in the elliptical galaxies NGC 5044 and NGC 5813

Plaa

Zhuravleva

Werner

et al. 2012

A&A

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Context. The interstellar and intra-cluster medium (ICM) in giant elliptical galaxies and clusters of galaxies is often assumed to be in hydrostatic equilibrium. Numerical simulations, however, show that about 5-30% of the pressure in a cluster is provided by turbulence induced by, for example, the central active galactic nucleus (AGN) and merger activity. Aims. We aim to put constraints on the turbulent velocities and the turbulent pressure in the ICM of the giant elliptical galaxies NGC 5044 and NGC 5813 using XMM-Newton reflection grating spectrometer (RGS) observations. Methods. The magnitude of the turbulence is estimated using the Fe xvii lines at 15.01 Å, 17.05 Å, and 17.10 Å in the RGS spectra. At low turbulent velocities, the gas becomes optically thick in the 15.01 Å line due to resonant scattering, while the 17 Å lines remain optically thin. By comparing the (I 17.05 + I 17.10 )/I 15.01 line ratio from RGS with simulated line ratios for different Mach numbers, the level of turbulence is constrained. The measurement is, however, limited by the systematic uncertainty in the line ratio for an optically thin plasma, which is about 20-30%. Results. We find that the (I 17.05 + I 17.10 )/I 15.01 line ratio in NGC 5813 is significantly higher than in NGC 5044. This difference can be explained by a higher level of turbulence in NGC 5044. The best estimates for the turbulent velocities using resonant scattering and upper limits from the line widths, are 320 < V turb < 720 km s −1 for NGC 5044 and 140 < V turb < 540 km s −1 for NGC 5813 at the 90% confidence limit. Conclusions. The high turbulent velocities and the fraction of the turbulent pressure support of >40% in NGC 5044, assuming isotropic turbulence, confirm that it is a highly disturbed system, probably due to an off-axis merger. The turbulent pressure support in NGC 5813 is more modest at 15-45%. The (I 17.05 + I 17.10 )/I 15.01 line ratio in an optically thin plasma, calculated using AtomDB v2.0.1, is 2σ above the ratio measured in NGC 5044, which cannot be explained by resonant scattering. This shows that the discrepancies between theoretical, laboratory, and astrophysical data on Fe xvii lines need to be reduced to improve the accuracy of the determination of turbulent velocities using resonant scattering.

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“…This feature is visible in all residual images we extracted under different geometries, as well as in an unsharp mask analysis performed as an additional check, and therefore we regard it as reliable. The shape of this feature recalls the spiral residuals that have been observed in a number of clusters (e.g., Laganá et al 2008, and, and in simulated residual images of sloshing clusters (e.g., Ascasibar & Markevitch 2006;Roediger et al 2011. They are interpreted as the signature of gas sloshing induced in the central cluster regions by minor mergers.…”

Section: Icm Structure Of A3560mentioning

confidence: 99%

Radio emission at the centre of the galaxy cluster Abell 3560: evidence for core sloshing?

Venturi

Rossetti

Bardelli

et al. 2013

A&A

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Context. We study the interplay between the radio emission associated with the dominant galaxy in clusters and the properties of the surrounding intracluster medium on the basis of its X-ray emission. Aims. Previous radio observations of the galaxy cluster A 3560, located in the Shapley Concentration core, revealed complex radio emission associated with the brightest cluster member. To understand the origin of this radio emission we performed a detailed multiwavelength study with high-quality proprietary data in the radio and X-ray bands and by means of optical data available in the literature. Methods. We observed the cluster with the Giant Metrewave Radio Telescope, the Very Large Array, and the Australia Telescope Compact array at 240 and 610 MHz, 1.28, 1.4, 2.3, 4.8, and 8.4 GHz, and performed a detailed morphological and spectral study of the radio emission associated with the brightest cluster galaxy (BCG). Furthermore, we observed the cluster with the XMM-Newton and Chandra observatories to derive the properties of the intracluster gas. Finally, we made use of literature data to obtain the bidimensional distribution of the galaxies in the cluster. Results. The radio emission, associated with the north-eastern nucleus of the dumb-bell BCG, is the result of two components: an active radio galaxy, with jets and lobes, plus aged diffuse emission, which is not refurbished with new electrons at present. Our Chandra data show that the radio active nucleus of the BCG has extended X-ray emission, which we classify as a low-luminosity corona. A residual image of the XMM-Newton brightness distribution shows a spiral-like feature, which we interpret as the signature of gas sloshing. A sub-group is clearly visible in the surface brightness residual map, and this is also supported by the XMM-Newton temperature analysis. The optical bidimensional analysis shows substructure in A 3560. A galaxy clump was detected at the location of the X-ray sub-group, and another group is present south of the cluster core, in the region where the spiral-like feature was detected. The aged part of the radio emission closely follows the spiral pattern of the X-ray residual brightness distribution, while the two active radio lobes are bent in a completely different direction. We conclude that the complex radio emission associated with the cluster BCG is the result of a minor merger event in A 3560. The aged diffuse emission is strongly affected by the sloshing motion in the intracluster gas and most likely bears information on the trajectory of the cluster BCG during the dynamical evolution of the cluster. On the other hand, the bent jets and lobes of the current radio AGN activity may reflect a complex gas velocity field in the innermost cluster regions and/or sloshing-induced oscillations in the motion of the cD galaxy.

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Gas sloshing, cold front formation and metal redistribution: the Virgo cluster as a quantitative test case

Cited by 142 publications

References 58 publications

The bow shock, cold fronts and disintegrating cool core in the merging galaxy group RX J0751.3+5012

The bow shock, cold fronts and disintegrating cool core in the merging galaxy group RX J0751.3+5012

Estimating turbulent velocities in the elliptical galaxies NGC 5044 and NGC 5813

Radio emission at the centre of the galaxy cluster Abell 3560: evidence for core sloshing?

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