scholarly journals Simulations of gas sloshing induced by a newly discovered gas poor substructure in galaxy cluster Abell 1644

2020 ◽  
Vol 495 (2) ◽  
pp. 2022-2034 ◽  
Author(s):  
L Doubrawa ◽  
R E G Machado ◽  
T F Laganá ◽  
G B Lima Neto ◽  
R Monteiro-Oliveira ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Nearby Galaxy ◽  
X Ray ◽  
Current State ◽  
History Of ◽  
Best Fitting ◽  
Hydrodynamical Simulations ◽  
Temperature Maps ◽  
Intracluster Gas ◽  
Good Agreement

ABSTRACT Collision events lead to peculiar morphologies in the intracluster gas of galaxies clusters. That seems to be the case of Abell 1644, a nearby galaxy cluster, composed of three main structures: the southern cluster that exhibits a spiral-like morphology, A1644S; the northern cluster seen in X-ray observations, A1644N1; and the recently discovered substructure, A1644N2. By means of N-body hydrodynamical simulations, we attempt to reconstruct the dynamical history of this system. These simulations resulted in two specific scenarios: (i) The collision between A1644S and A1644N2. Our best model has an inclination between the merger plane and the plane of the sky of 30°, and reaches the best morphology 1.6 Gyr after the pericentric passage. At this instant A1644N2 is gas poor, becoming nearly undetectable in X-ray emission. This model shows a good agreement with observations; (ii) The collision between A1644S and A1644N1. This approach did not give rise to results as satisfactory as the first scenario, due to great disturbances in density and mismatching temperature maps. As a complementary study, we perform a three-cluster simulation using as base the best-fitting model to reproduce the current state of A1644 with the three main structures. This scenario presented a good agreement to the global morphology of the observations. Thus, we find that the more likely scenario is a collision between A1644S and the newly discovered A1644N2, where A1644N1 may be present as long as it does not greatly interfere in the formation of the spiral feature.

scholarly journals Simulations of the merging galaxy cluster Abell 2034: what determines the level of separation between gas and dark matter

2020 ◽  
Vol 500 (2) ◽  
pp. 1858-1869 ◽  
Author(s):  
Micheli T Moura ◽  
Rubens E G Machado ◽  
Rogério Monteiro-Oliveira
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Galaxy Cluster ◽  
X Rays ◽  
X Ray ◽  
History Of ◽  
Hydrodynamical Simulations ◽  
Cluster Mergers ◽  
Cluster Cores ◽  
Intracluster Gas

ABSTRACT Cluster mergers are an important laboratory for studying the behaviour of dark matter (DM) and intracluster gas. There are dissociative collisions that can separate the intracluster gas from the DM. Abell 2034 presents clear dissociative features observed by X-rays and gravitational lensing. The cluster, at z = 0.114, consists of two substructures with mass ratio of about 1:2.2, separated by ∼720 kpc. The X-ray emission peak is offcentred from the south DM peak by ∼350 kpc. Using N-body hydrodynamical simulations, we aim to reconstruct the dynamic history of the collision, reproducing the observed features, and also to explore the conditions that led to the dissociation. Our best model assuming that the collision is close to the plane of the sky, with a small impact parameter, observed 0.26 Gyr after central passage, reproduces the observed features of this cluster, such as the offset between X-ray and DM peaks, X-ray morphology, and temperatures. We explored several variations using different gas and DM concentrations for each cluster. The level of dissociation was quantified by the distances between X-ray and DM peaks, and also by the gas retention in the cluster cores. We found that the ratio of central gas densities is more important than the ratio of central DM densities in determining the level of dissociation.

scholarly journals The galaxy cluster ‘Pypeline’ for X-ray temperature maps: ClusterPyXT

2019 ◽  
Vol 27 ◽  
pp. 147-155 ◽  
Author(s):  
B. Alden ◽  
E.J. Hallman ◽  
D. Rapetti ◽  
J.O. Burns ◽  
A. Datta
Keyword(s):  
Galaxy Cluster ◽  
X Ray ◽  
The Galaxy ◽  
Temperature Maps

scholarly journals X-ray Spectra of Clusters of Galaxies

1990 ◽  
Vol 115 ◽  
pp. 209-218 ◽  
Author(s):  
Craig L. Sarazin
Keyword(s):  
High Resolution ◽  
Absorption Line ◽  
Physical State ◽  
Thermal Emission ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Line Measurement ◽  
History Of ◽  
Intracluster Gas ◽  
X Ray Absorption

AbstractX-ray line observations of clusters of galaxies have shown that the X-ray emission in clusters is mainly thermal emission from hot diffuse gas, and that much of this gas has come out of stars, probably having been ejected from galaxies in the cluster. Future high resolution observations should allow us to determine the physical state of the gas. X-ray line measurements and abundance determinations can lead to strong constraints on the origin of the intracluster gas, and on the chemical evolution and history of galaxies. Some of the stronger resonant X-ray lines may be observable as absorption lines against a background quasar. Such X-ray absorption line measurement can be used to directly derive distances to clusters, using a technique similar to (and possibly complementary to) that the well-known method using the Zel’dovich-Syunyaev effect.

scholarly journals The effect of AGN feedback on Sunyaev-Zeldovich properties of simulated galaxy clusters

2016 ◽  
Vol 12 (S324) ◽  
pp. 237-238
Author(s):  
Dunja Fabjan ◽  
S. Planelles ◽  
S. Borgani ◽  
G. Murante ◽  
E. Rasia ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Clusters ◽  
State Of The Art ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Stellar Feedback ◽  
The Galaxy ◽  
History Of ◽  
Hydrodynamical Simulations ◽  
Massive Clusters

AbstractWe studied the imprints that feedback from Active Galactic Nuclei (AGN) leaves on the intracluster plasma during the assembly history of galaxy clusters. To this purpose we used state-of-the-art cosmological hydrodynamical simulations based on an updated version of the Tree-PM SPH GADGET-3 code, comparing three sets of simulations with different prescriptions for the physics of baryons (including AGN and/or stellar feedback). We explore the effect of these different physics, in particular AGN feedback, on IntraCluster medium (ICM) properties observed via Sunyaev-Zel’dovich (SZ) effect using an extended set of galaxy clusters (~100 clusters with M500 masses above 5 × 1013M⊙/h). Some of the main findings are that the scaling relation between the integrated SZ flux and the galaxy cluster total mass is in good accordance with several observed samples, especially for massive clusters, and does not show any clear redshift evolution, with the slope of the relation close to the theoretical one in the AGN feedback case. As for the scatter of this relation, we obtain a mild dependence on the cluster dynamical state.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A2 ◽  
Author(s):  
A. B. Mantz ◽  
Z. Abdulla ◽  
S. W. Allen ◽  
J. E. Carlstrom ◽  
C. H. A. Logan ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Limited Information ◽  
X Ray ◽  
Average Temperature ◽  
Mass Estimate ◽  
Self Similar ◽  
Single Cluster ◽  
Lower Redshift ◽  
Massive Cluster ◽  
Good Agreement

We present results from a 100 ks XMM-Newton observation of galaxy cluster XLSSC 122, the first massive cluster discovered through its X-ray emission at z ≈ 2. The data provide the first precise constraints on the bulk thermodynamic properties of such a distant cluster, as well as an X-ray spectroscopic confirmation of its redshift. We measure an average temperature of kT = 5.0 ± 0.7 keV; a metallicity with respect to solar of Z/Z⊙ = 0.33−0.17+0.19, consistent with lower-redshift clusters; and a redshift of z = 1.99+0.07-0.06 , consistent with the earlier photo-z estimate. The measured gas density profile leads to a mass estimate at r500 of M500 = (6.3 ± 1.5) × 1013 M⊙. From CARMA 30 GHz data, we measure the spherically integrated Compton parameter within r500 to be Y 500 = (3.6 ± 0.4) × 10−12. We compare the measured properties of XLSSC 122 to lower-redshift cluster samples, and find good agreement when assuming the simplest (self-similar) form for the evolution of cluster scaling relations. While a single cluster provides limited information, this result suggests that the evolution of the intracluster medium in the most massive, well-developed clusters is remarkably simple, even out to the highest redshifts where they have been found. At the same time, our data reaffirm the previously reported spatial offset between the centres of the X-ray and SZ signals for XLSSC 122, suggesting a disturbed configuration. Higher spatial resolution data could thus provide greater insights into the internal dynamics of this system.

scholarly journals WINGS: WIde-field Nearby Galaxy-cluster Survey

2006 ◽  
Vol 2 (S235) ◽  
pp. 246-253
Author(s):  
Jesús Varela ◽  
Keyword(s):  
Galaxy Cluster ◽  
Zero Point ◽  
Current Status ◽  
Wide Field ◽  
Nearby Galaxy ◽  
X Ray ◽  
Line Section ◽  
Local Reference ◽  
On Line

AbstractThe WIde-field Nearby Galaxy-cluster Survey (WINGS) is a long term project whose main goal is to establish the zero point and variance of properties of nearby clusters, and galaxies in them, to be used as a local reference in evolutionary studies.To achieve such objective, wide-field multiwavelenght photometry and optical spectroscopy has been gathered and analysed for a sample of 77 X-ray emitting nearby galaxy clusters.This contribution shows the current status of the project.Complete poster contents is reproduced in “On-line Section” and PDF copy is available in http://web.oapd.inaf.it/wings/Docs/IAU2006_Varela.pdf.

scholarly journals First measurement of the cross-correlation between CMB weak lensing and X-ray emission

2019 ◽  
Vol 625 ◽  
pp. L4 ◽  
Author(s):  
G. Hurier ◽  
P. Singh ◽  
C. Hernández-Monteagudo
Keyword(s):  
Cross Correlation ◽  
Power Spectra ◽  
Galaxy Cluster ◽  
Weak Lensing ◽  
X Rays ◽  
Satellite Mission ◽  
Local Universe ◽  
Best Fitting ◽  
The Cross ◽  
Hydrodynamical Simulations

Since the publication of the results of the Planck satellite mission in 2013, the local and early Universes have been considered to be in tension in respect of the determination of amplitude of the matter density spatial fluctuations (σ8) and the amount of matter present in the Universe (Ωm). This tension can be seen as a lack of massive galaxy clusters in the local Universe compared to the prediction inferred from Planck cosmic microwave background (CMB) best-fitting cosmology. In the present analysis we perform the first detection of the cross-correlation between X-rays and CMB weak lensing at 9.1σ. We next combine thermal Sunyaev–Zel’dovich effect, X-rays, and weak-lensing angular auto- and cross-correlation power spectra to determine the galaxy cluster hydrostatic mass bias. We derive (1 − bH) = 0.71 ± 0.07. Considering these constraints, we observe that estimations of σ8 in the local Universe are consistent with Planck CMB best-fitting cosmology. However, these results are in clear tension with the output of hydrodynamical simulations that favor (1 − bH)> 0.8.

scholarly journals On the peculiar torque reversals and the X-ray luminosity history of the accretion-powered X-ray pulsar 4U 1626–67

2020 ◽  
Vol 495 (4) ◽  
pp. 3531-3537 ◽  
Author(s):  
O Benli
Keyword(s):  
Accretion Rate ◽  
Rotation Axis ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Spin Period ◽  
Substantial Modification ◽  
Oblique Rotator ◽  
Period Derivative ◽  
History Of ◽  
Best Fitting

ABSTRACT The X-ray luminosity (Lx) and the rotational properties of 4U 1626–67 have been measured at regular intervals during the last four decades. It has been recorded that the source underwent torque reversals twice. We have tried to understand whether these eccentrical sign-switches of the spin period derivative ($\dot{P}$) of 4U 1626–67 could be accounted for with the existing torque models. We have found that the observed source properties are better estimated with the distances close to the lower limit of the previously predicted distance range (5−13 kpc). Furthermore, assuming an inclined rotator, we have considered the partial accretion/ejection from the inner disc radius that leads to different Lx–$\dot{P}$ profiles than the aligned rotator cases. We have concluded that the oblique rotator assumption with the inclination angle χ ∼ (10°−30°) brings at least equally best fitting to the observed Lx and $\dot{P}$ of 4U 1626–67. More importantly, the estimated change of the mass accretion rate, which causes the change in observed Lx of 4U 1626–67 is much less than that is found in an aligned rotator case. In other words, without the need for a substantial modification of mass accretion rate from the companion star, the range of the observed Lx could be explained naturally with an inclined magnetic axis and rotation axis of the neutron star.

scholarly journals Particle acceleration in a nearby galaxy cluster pair: the role of cluster dynamics

2019 ◽  
Vol 630 ◽  
pp. A77 ◽  
Author(s):  
A. Botteon ◽  
R. Cassano ◽  
D. Eckert ◽  
G. Brunetti ◽  
D. Dallacasa ◽  
...  
Keyword(s):  
Radio Emission ◽  
Galaxy Clusters ◽  
Surface Brightness ◽  
Power Spectra ◽  
Galaxy Cluster ◽  
Cluster Center ◽  
Nearby Galaxy ◽  
X Ray ◽  
Radio Halo ◽  
Cluster Pair

Context. Diffuse radio emission associated with the intracluster medium (ICM) is observed in a number of merging galaxy clusters. It is currently believed that a fraction of the kinetic energy in mergers is channeled into nonthermal components, such as turbulence, cosmic rays, and magnetic fields, which may lead to the formation of giant synchrotron sources in the ICM. Aims. Studying merging galaxy clusters in different evolutionary phases is fundamental for understanding the origin of radio emission in the ICM. Methods. We observed the nearby galaxy cluster pair RXC J1825.3+3026 (z ∼ 0.065) and CIZA J1824.1+3029 (z ∼ 0.071) at 120 − 168 MHz with the LOw Frequency ARray (LOFAR) and made use of a deep (240 ks) XMM-Newton dataset to study the nonthermal and thermal properties of the system. RXC J1825.3+3026 is in a complex dynamical state, with a primary ongoing merger in the E-W direction and a secondary later stage merger with a group of galaxies in the SW, while CIZA J1824.1+3029 is dynamically relaxed. These two clusters are in a pre-merger phase. Results. We report the discovery of a Mpc-scale radio halo with a low surface brightness extension in RXC J1825.3+3026 that follows the X-ray emission from the cluster center to the remnant of a galaxy group in the SW. This is among the least massive systems and the faintest giant radio halo known to date. In contrast to this, no diffuse radio emission is observed in CIZA J1824.1+3029, nor in the region between the pre-merger cluster pair. The power spectra of the X-ray surface brightness fluctuations of RXC J1825.3+3026 and CIZA J1824.1+3029 are in agreement with the findings for clusters exhibiting a radio halo and clusters where no radio emission has been detected, respectively. Conclusions. We provide quantitative support to the idea that cluster mergers play a crucial role in the generation of nonthermal components in the ICM.

scholarly journals The Metal Content of the Hot Atmospheres of Galaxy Groups

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 208
Author(s):  
Fabio Gastaldello ◽  
Aurora Simionescu ◽  
Francois Mernier ◽  
Veronica Biffi ◽  
Massimo Gaspari ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Mass Scale ◽  
Chemical Abundances ◽  
Abundance Pattern ◽  
X Ray ◽  
Galaxy Groups ◽  
Chemical Enrichment ◽  
Metal Contents ◽  
History Of ◽  
Hydrodynamical Simulations

Galaxy groups host the majority of matter and more than half of all the galaxies in the Universe. Their hot (107 K), X-ray emitting intra-group medium (IGrM) reveals emission lines typical of many elements synthesized by stars and supernovae. Because their gravitational potentials are shallower than those of rich galaxy clusters, groups are ideal targets for studying, through X-ray observations , feedback effects, which leave important marks on their gas and metal contents. Here, we review the history and present status of the chemical abundances in the IGrM probed by X-ray spectroscopy. We discuss the limitations of our current knowledge, in particular due to uncertainties in the modeling of the Fe-L shell by plasma codes, and coverage of the volume beyond the central region. We further summarize the constraints on the abundance pattern at the group mass scale and the insight it provides to the history of chemical enrichment. Parallel to the observational efforts, we review the progress made by both cosmological hydrodynamical simulations and controlled high-resolution 3D simulations to reproduce the radial distribution of metals in the IGrM, the dependence on system mass from group to cluster scales, and the role of AGN and SN feedback in producing the observed phenomenology. Finally, we highlight future prospects in this field, where progress will be driven both by a much richer sample of X-ray emitting groups identified with eROSITA, and by a revolution in the study of X-ray spectra expected from micro-calorimeters onboard XRISM and ATHENA.

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