Metal jumps across sloshing cold fronts: The case of A 496

Ghizzardi, S.; Grandi, S. De; Molendi, S.

doi:10.1002/asna.201211871

Cited by 11 publications

(9 citation statements)

References 20 publications

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“…We have shown that in relaxed (e.g. Ghizzardi et al 2013) and intermediate systems ) entropy and metallicity tend to anti-correlate, i.e. regions of lower entropy are more metal-rich.…”

Section: Abundance Bias In the Outskirtsmentioning

confidence: 88%

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A critical assessment of the metal content of the intracluster medium

Molendi

Eckert

Grandi

et al. 2016

A&A

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Aims. Our goal is to provide a robust estimate of the metal content of the intracluster medium (ICM) in massive clusters. Methods. We made use of published abundance profiles for a sample of ∼60 nearby systems. We included in our estimate uncertainties associated with the measurement process and with the almost total lack of information in cluster outskirts.Results. We performed a first, albeit rough, census of metals and find that the mean abundance of the ICM within r 180 is very poorly constrained, 0.06 Z Z 0.26 Z and presents no disagreement with expectations. Similarly, whether and how the bulk of the metal content in clusters varies with cosmic time are very much open questions. Conclusions. A solid estimate of abundances in cluster outskirts could be achieved by combining observations of the two experiments that will operate on board Athena, the XIFU and the WFI, provided they do not fall victim to the de-scoping process that has afflicted several space observatories over the last decade.

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“…We have shown that in relaxed (e.g. Ghizzardi et al 2013) and intermediate systems ) entropy and metallicity tend to anti-correlate, i.e. regions of lower entropy are more metal-rich.…”

Section: Abundance Bias In the Outskirtsmentioning

confidence: 88%

“…For example some have attempted to use metals as tracers of gas motions in the ICM (e.g. Ghizzardi et al 2013;. A few (e.g.…”

Section: Introductionmentioning

confidence: 99%

A critical assessment of the metal content of the intracluster medium

Molendi

Eckert

Grandi

et al. 2016

A&A

Self Cite

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“…Previously analysed metallicity profiles, based on deprojected (Sanders et al 2005), but more often projected (e.g., Ghizzardi et al 2007;Rossetti et al 2007;Simionescu et al 2010;Fabian et al 2011;Russell et al 2012;Ghizzardi et al 2013;Walker et al 2017), data, suggested a sharp drop in Z across CFs, qZ ≡ Zi/Zo > 1. The only metallicity profiles that were, as far as we know, previously deprojected across a CF (Sanders et al 2005(Sanders et al , 2016, suggested such a drop at only marginal, 2σ confidence levels.…”

Section: Metallicity Dropsmentioning

confidence: 99%

Deprojecting galaxy-cluster cold fronts: evidence for bulk, magnetised spiral flows

Naor,

Keshet,

Wang

et al. 2020

Preprint

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Tangential discontinuities known as cold fronts (CFs) are abundant in groups and clusters of galaxies (GCs). The relaxed, spiral-type CFs were initially thought to be isobaric, but a significant, 10%-20% jump in the thermal pressure P t was reported when deprojected CFs were stacked, interpreted as missing P t below the CFs (i.e. at smaller radii r) due to a locally-enhanced nonthermal pressure P nt . We report a significant (∼ 4.3σ) deprojected jump in P t across a single sharp CF in the Centaurus cluster. Additional seven CFs are deprojected in the GCs A2029, A2142, A2204, and Centaurus, all found to be consistent (stacked: ∼ 1.9σ) with similar pressure jumps. Combining our sample with high quality deprojected CFs from the literature indicates pressure jumps at significance levels ranging between 2.7σ and 5.0σ, depending on assumptions. Our nominal results are consistent with P nt ≃ (0.1-0.3)P t just below the CF. We test different deprojection and analysis methods to confirm that our results are robust, and show that without careful deprojection, an opposite pressure trend may incorrectly be inferred. Analysing all available deprojected data, we also find: (i) a nearly constant CF contrast q of density and temperature within each GC, monotonically increasing with the GC mass M 200 as q ∝ M 0.23±0.04 200 ; (ii) hydrostatic mass discontinuities indicating fast bulk tangential flows below all deprojected CFs, with a mean Mach number ∼ 0.76; and (iii) the newly deprojected CFs are consistent (stacked: ∼ 2.9σ) with a 1.25 +0.09 −0.08 metallicity drop across the CF. These findings suggest that GCs quite generally harbor extended spiral flows.

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“…The oscillations occur in the plane of the orbit of the infalling perturber. When this plane is close to the plane of the sky, the sloshing produces a characteristic spiral pat- tern in surface brightness residuals, temperature and abundances, as cool, enriched gas is left behind by the motion of the core and warmer gas is drawn inwards (e.g., Roediger et al 2012;Gastaldello et al 2013;Ghizzardi et al 2013;Su et al 2017). However, when the plane is orthogonal to the plane of the sky, our line of sight passes through the spiral, producing alternating positive and negative arc-shaped residuals to either side of the core as in, e.g., the galaxy group NGC 5044 (O'Sullivan et al 2014) or galaxy clusters such as Abell 1795 (Markevitch et al 2001;Ehlert et al 2015), Abell 2219 (Canning et al 2017) or Abell 1664 (Calzadilla et al 2019).…”

Section: Sloshingmentioning

confidence: 99%

Evidence of AGN feedback and sloshing in the X-ray luminous NGC 1550 galaxy group

Kolokythas,

O'Sullivan,

Giacintucci

et al. 2020

Preprint

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We present results from GMRT and Chandra observations of the NGC 1550 galaxy group. Although previously thought of as relaxed, we show evidence that gas sloshing and active galactic nucleus (AGN) heating have affected the structure of the system. The 610 and 235 MHz radio images show an asymmetric jet−lobe structure with a total size of ∼33 kpc, with a sharp kink at the base of the more extended western jet, and bending of the shorter eastern jet as it enters the lobe. The 235−610 MHz spectral index map shows that both radio lobes have steep spectral indices (α 610 235 ≥ −1.5) indicating the presence of an old electron population. The X-ray images reveal an asymmetric structure in the hot gas correlated with the radio structure, as well as potential cavities coincident with the radio lobes, with rims and arms of gas that may have been uplifted by the cavity expansion. The X-ray residual map reveals an arc shaped structure to the east that resembles a sloshing cold front. Radio spectral analysis suggests a radiative age of about 33 Myr for the source, comparable to the sloshing timescale and dynamical estimates of the age of the lobes. An estimate of the mechanical energy required to inflate the cavities suggests that the AGN of NGC 1550 is capable of balancing radiative losses from the intragroup medium (IGM) and preventing excessive cooling, providing that the AGN jets are efficiently coupled to the IGM gas. In conclusion, we find evidence of sloshing motions from both radio and X-ray structures, suggesting that NGC 1550 was perturbed by a minor merger or infalling galaxy about 33 Myr ago.

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Metal jumps across sloshing cold fronts: The case of A 496

Cited by 11 publications

References 20 publications

A critical assessment of the metal content of the intracluster medium

A critical assessment of the metal content of the intracluster medium

Deprojecting galaxy-cluster cold fronts: evidence for bulk, magnetised spiral flows

Evidence of AGN feedback and sloshing in the X-ray luminous NGC 1550 galaxy group

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