Study of Galaxy Cluster Properties from High-Resolution SPH Simulations

ABSTRACT We present the first high-resolution 230–470 MHz map of the Perseus cluster obtained with the Karl G. Jansky Very Large Array. The high dynamic range and resolution achieved have allowed the identification of previously unknown structures in this nearby galaxy cluster. New hints of sub-structures appear in the inner radio lobes of the brightest cluster galaxy NGC 1275. The spurs of radio emission extending into the outer X-ray cavities, inflated by past nuclear outbursts, are seen for the first time at these frequencies, consistent with spectral aging. Beyond NGC 1275, we also analyse complex radio sources harboured in the cluster. Two new distinct, narrowly collimated jets are visible in IC 310, consistent with a highly projected narrow-angle tail radio galaxy infalling into the cluster. We show how this is in agreement with its blazar-like behaviour, implying that blazars and bent-jet radio galaxies are not mutually exclusive. We report the presence of filamentary structures across the entire tail of NGC 1265, including two new pairs of long filaments in the faintest bent extension of the tail. Such filaments have been seen in other cluster radio sources such as relics and radio lobes, indicating that there may be a fundamental connection between all these radio structures. We resolve the very narrow and straight tail of CR 15 without indication of double jets, so that the interpretation of such head–tail sources is yet unclear. Finally, we note that only the brightest western parts of the mini-halo remain, near NGC 1272 and its bent double jets.

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Projection effects in galaxy cluster samples: insights from X-ray redshifts

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935111 ◽

2019 ◽

Vol 626 ◽

pp. A48 ◽

Cited By ~ 4

Author(s):

M. E. Ramos-Ceja ◽

F. Pacaud ◽

T. H. Reiprich ◽

K. Migkas ◽

L. Lovisari ◽

...

Keyword(s):

Spatial Information ◽

Galaxy Cluster ◽

X Rays ◽

X Ray ◽

Cluster Sample ◽

Global Cluster ◽

Sky Survey ◽

The Galaxy ◽

Flux Measurements ◽

Cluster Properties

Presently, the largest sample of galaxy clusters selected in X-rays comes from the ROSAT All-Sky Survey (RASS). Although there have been many interesting clusters discovered with the RASS data, the broad point spread function of the ROSAT satellite limits the attainable amount of spatial information for the detected objects. This leads to the discovery of new cluster features when a re-observation is performed with higher-resolution X-ray satellites. Here we present the results from XMM-Newton observations of three clusters: RXC J2306.6−1319, ZwCl 1665, and RXC J0034.6−0208, for which the observations reveal a double or triple system of extended components. These clusters belong to the extremely expanded HIghest X-ray FLUx Galaxy Cluster Sample (eeHIFLUGCS), which is a flux-limited cluster sample (fX, 500 ≥ 5 × 10−12 erg s−1 cm−2 in the 0.1−2.4 keV energy band). For each structure in each cluster, we determine the redshift with the X-ray spectrum and find that the components are not part of the same cluster. This is confirmed by an optical spectroscopic analysis of the galaxy members. Therefore, the total number of clusters is actually seven, rather than three. We derive global cluster properties of each extended component. We compare the measured properties to lower-redshift group samples, and find a good agreement. Our flux measurements reveal that only one component of the ZwCl 1665 cluster has a flux above the eeHIFLUGCS limit, while the other clusters will no longer be part of the sample. These examples demonstrate that cluster–cluster projections can bias X-ray cluster catalogues and that with high-resolution X-ray follow-up this bias can be corrected.

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An analysis of galaxy cluster mis-centring using cosmological hydrodynamic simulations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa295 ◽

2020 ◽

Vol 493 (1) ◽

pp. 1120-1129

Author(s):

Z Yan ◽

N Raza ◽

L Van Waerbeke ◽

A J Mead ◽

I G McCarthy ◽

...

Keyword(s):

Galaxy Cluster ◽

Mass Range ◽

Three Dimensions ◽

Cumulative Distribution ◽

Density Profiles ◽

Hydrodynamic Simulations ◽

The Galaxy ◽

Cluster Density ◽

Cluster Properties ◽

Using Data

ABSTRACT The location of a galaxy cluster’s centroid is typically derived from observations of the galactic and/or gas component of the cluster, but these typically deviate from the true centre. This can produce bias when observations are combined to study average cluster properties. Using data from the BAryons and HAloes of MAssive Systems (BAHAMAS) cosmological hydrodynamic simulations, we study this bias in both two and three dimensions for 2000 clusters over the 1013–1015 M⊙ mass range. We quantify and model the offset distributions between observationally motivated centres and the ‘true’ centre of the cluster, which is taken to be the most gravitationally bound particle measured in the simulation. We fit the cumulative distribution function of offsets with an exponential distribution and a Gamma distribution fit well with most of the centroid definitions. The galaxy-based centres can be seen to be divided into a mis-centred group and a well-centred group, with the well-centred group making up about $60{{\ \rm per\ cent}}$ of all the clusters. Gas-based centres are overall less scattered than galaxy-based centres. We also find a cluster-mass dependence of the offset distribution of gas-based centres, with generally larger offsets for smaller mass clusters. We then measure cluster density profiles centred at each choice of the centres and fit them with empirical models. Stacked, mis-centred density profiles fit to the Navarro–Frenk–White dark matter profile and Komatsu–Seljak gas profile show that recovered shape and size parameters can significantly deviate from the true values. For the galaxy-based centres, this can lead to cluster masses being underestimated by up to $10{{\ \rm per\ cent}}$.

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Towards a better understanding of galaxy clusters

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314010886 ◽

2014 ◽

Vol 10 (S306) ◽

pp. 273-275

Author(s):

Pedro T. P. Viana

Keyword(s):

Distribution Function ◽

Probability Distribution ◽

Probability Distribution Function ◽

Large Scale ◽

Posterior Probability ◽

Galaxy Cluster ◽

Relevant Information ◽

Posterior Probability Distribution ◽

Cluster Properties ◽

The Universe

AbstractObservational data on clusters of galaxies holds relevant information that can be used to determine the relative plausibility of different models for the large-scale evolution of the Universe, or estimate the joint posterior probability distribution function of the parameters that pertain to each model. Within the next few years, several surveys of the sky will yield large galaxy cluster catalogues. In order to make use of the vast amount of information they will contain, their selection functions will have to be properly understood. We argue this, as well as the estimation of the full joint posterior probability distribution function of the most relevant cluster properties, can be best achieved in the framework of bayesian statistics.

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Evidence of an interaction between jets and intra-cluster magnetic layer

10.21203/rs.3.rs-81320/v1 ◽

2020 ◽

Author(s):

James Chibueze ◽

Haruka Sakemi ◽

Takumi Ohmura ◽

Mami Machida ◽

Hiroki Akamatsu ◽

...

Keyword(s):

Magnetic Field ◽

High Resolution ◽

Radio Galaxy ◽

Dense Plasma ◽

Contact Discontinuity ◽

Magnetic Layer ◽

Galaxy Cluster ◽

Cosmic Ray ◽

Relativistic Electrons ◽

Cluster Member

Abstract Galaxy clusters are known to harbor magnetic field, however, the extent of the influence of the intra-cluster magnetic field on the cluster member galaxies remains an unresolved question. Intra-cluster magnetic field can be observed as density contact discontinuity formed by cool and dense plasma running into hot ambient plasma, and this exist in the central region of a merging galaxy cluster Abell 3376. Here we report on unambiguous evidence of an interaction between the relativistic electrons and intra-cluster magnetic fields from MeerKAT observations of a radio galaxy MRC0600-399, having bent jets. Contrary to typical bent jets, the jet shows a 90 degrees bend at the contact discontinuity and the collimated jet further extends over 100 kpc from the bend point. The spectral index flattens downstream of the bend point, indicating cosmic-ray re-acceleration. High-resolution numerical simulations reveal that the ordered magnetic field along the discontinuity, at which the intra-cluster magnetic field can be compressed and amplified, plays a significant role to the change in the direction of the jet propagation. The overall morphology of the bent jet bears remarkable similarities with the simulations, which greatly strengthens our understanding of the interaction between relativistic electrons and intra-cluster magnetic field.

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Investigating the Relationship Between the Hot Gas and the Dark Matter Components of Galaxy Clusters.

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307014342 ◽

2007 ◽

Vol 3 (S244) ◽

pp. 374-375

Author(s):

Leila C. Powell ◽

Scott T. Kay ◽

Arif Babul ◽

Andisheh Mahdavi

Keyword(s):

Dark Matter ◽

Total Mass ◽

Surface Brightness ◽

Galaxy Cluster ◽

Weak Lensing ◽

X Ray ◽

Hot Gas ◽

Cluster Properties ◽

The Impact ◽

The Relationship

AbstractVarious differences in galaxy cluster properties derived from X-ray and weak lensing observations have been highlighted in the literature. One such difference is the observation of mass concentrations in lensing maps which have no X-ray counterparts (e.g. Jee, White, Ford et al. 2005). We investigate this issue by identifying substructures in maps of projected total mass (analogous to weak lensing mass reconstructions) and maps of projected X-ray surface brightness for three simulated clusters. We then compare the 2D mass substructures with both 3D subhalo data and the 2D X-ray substructures. Here we present preliminary results from the first comparison, where we have assessed the impact of projecting the data on subhalo identification.

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A HIGH-RESOLUTION MASS MAP OF GALAXY CLUSTER SUBSTRUCTURE: LensPerfect ANALYSIS OF A1689

The Astrophysical Journal ◽

10.1088/0004-637x/723/2/1678 ◽

2010 ◽

Vol 723 (2) ◽

pp. 1678-1702 ◽

Cited By ~ 65

Author(s):

Dan Coe ◽

Narciso Benítez ◽

Tom Broadhurst ◽

Leonidas A. Moustakas

Keyword(s):

High Resolution ◽

Galaxy Cluster ◽

High Resolution Mass ◽

Resolution Mass

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A low-mass galaxy cluster as a test-case study for the NIKA2 SZ Large Program

EPJ Web of Conferences ◽

10.1051/epjconf/202022800012 ◽

2020 ◽

Vol 228 ◽

pp. 00012 ◽

Cited By ~ 1

Author(s):

F. Kéruzoré ◽

R. Adam ◽

P. Ade ◽

P. André ◽

A. Andrianasolo ◽

...

Keyword(s):

High Resolution ◽

Galaxy Clusters ◽

High Redshift ◽

Galaxy Cluster ◽

Mass Range ◽

Point Sources ◽

Test Case ◽

Low Snr ◽

Main Challenge ◽

Large Program

High-resolution mapping of the hot gas in galaxy clusters is a key tool for cluster-based cosmological analyses. Taking advantage of the NIKA2 millimeter camera operated at the IRAM 30-m telescope, the NIKA2 SZ Large Program seeks to get a high-resolution follow-up of 45 galaxy clusters covering a wide mass range at high redshift in order to re-calibrate some of the tools needed for the cosmological exploitation of SZ surveys. We present the second cluster analysis of this program, targeting one of the faintest sources of the sample in order to tackle the difficulties in data reduction for such faint, low-SNR clusters. In this study, the main challenge is the precise estimation of the contamination by sub-millimetric point sources, which greatly affects the tSZ map of the cluster. We account for this contamination by performing a joint fit of the SZ signal and of the flux density of the compact sources. A prior knowledge of these fluxes is given by the adjustment of the SED of each source using data from both NIKA2 and the Herschel satellite. The first results are very promising and demonstrate the possibility to estimate thermodynamic properties with NIKA2, even in a compact cluster heavily contaminated by point sources.

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