scholarly journals On the relation between mini-halos and AGN feedback in clusters of galaxies

2020 ◽  
Vol 499 (2) ◽  
pp. 2934-2958
Author(s):  
A Richard-Laferrière ◽  
J Hlavacek-Larrondo ◽  
R S Nemmen ◽  
C L Rhea ◽  
G B Taylor ◽  
...  
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Vital Role ◽  
Clusters Of Galaxies ◽  
Relativistic Jets ◽  
X Ray ◽  
Core Cluster ◽  
Central Galaxy ◽  
Central Regions ◽  
Radio Power

ABSTRACT A variety of large-scale diffuse radio structures have been identified in many clusters with the advent of new state-of-the-art facilities in radio astronomy. Among these diffuse radio structures, radio mini-halos are found in the central regions of cool core clusters. Their origin is still unknown and they are challenging to discover; less than 30 have been published to date. Based on new VLA observations, we confirmed the mini-halo in the massive strong cool core cluster PKS 0745−191 (z = 0.1028) and discovered one in the massive cool core cluster MACS J1447.4+0827 (z = 0.3755). Furthermore, using a detailed analysis of all known mini-halos, we explore the relation between mini-halos and active galactic nucleus (AGN) feedback processes from the central galaxy. We find evidence of strong, previously unknown correlations between mini-halo radio power and X-ray cavity power, and between mini-halo and the central galaxy radio power related to the relativistic jets when spectrally decomposing the AGN radio emission into a component for past outbursts and one for ongoing accretion. Overall, our study indicates that mini-halos are directly connected to the central AGN in clusters, following previous suppositions. We hypothesize that AGN feedback may be one of the dominant mechanisms giving rise to mini-halos by injecting energy into the intra-cluster medium and reaccelerating an old population of particles, while sloshing motion may drive the overall shape of mini-halos inside cold fronts. AGN feedback may therefore not only play a vital role in offsetting cooling in cool core clusters, but may also play a fundamental role in re-energizing non-thermal particles in clusters.

scholarly journals Thomson linac-based X-ray generator: a primer for theory and design

2016 ◽  
Vol 34 (4) ◽  
pp. 637-644 ◽  
Author(s):  
I.A. Artyukov ◽  
E.G. Bessonov ◽  
M.V. Gorbunkov ◽  
Y.Y. Maslova ◽  
N.L. Popov ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Laser Radiation ◽  
Conceptual Design ◽  
Large Scale ◽  
State Of The Art ◽  
Thomson Scattering ◽  
Powerful Laser ◽  
X Ray ◽  
X Ray Imaging

AbstractThe paper presents a general theoretical framework and related Monte Carlo simulation of novel type of the X-ray sources based on relativistic Thomson scattering of powerful laser radiation. Special attention is paid to the linac X-ray generators by way of two examples: conceptual design for production of 12.4 keV photons and presently operating X-ray source of 29.4 keV photons. Our analysis shows that state-of-the-art laser and accelerator technologies enable to build up a compact linac-based Thomson source for the same X-ray imaging and diffraction experiments as in using of a large-scale X-ray radiation facility like a synchrotron or Thomson generator based on electron storage ring.

scholarly journals High Resolution X-ray Spectroscopy of Active Galactic Nuclei

1990 ◽  
Vol 115 ◽  
pp. 262-273
Author(s):  
Julian H. Krolik
Keyword(s):  
High Resolution ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Light Sources ◽  
Clusters Of Galaxies ◽  
Relativistic Jets ◽  
Bl Lac Objects ◽  
X Ray ◽  
Interstellar Material ◽  
Scientific Value

AbstractHigh-resolution X-ray spectroscopy has the potential to reveal a number of interesting features of active galactic nuclei, primarily, though not exclusively, through the measurement of absorption lines. After a brief review of the principal problems of AGN research, selected potential high-resolution observations are discussed with a view toward assessing their scientific value and the degree of resolution they will require. Two classes of observations pertaining directly to AGNs are discussed: Fe Kα spectroscopy relevant to the dynamical and thermal character of the emission line zones; and measurement of resonance line absorption by highly-ionized species in BL Lac objects, which should tell us about entrainment of interstellar material by relativistic jets. A third class of potentially important observations uses AGNs as background light sources in order to directly measure the distance to clusters of galaxies.

scholarly journals Planck intermediate results

2018 ◽  
Vol 617 ◽  
pp. A48 ◽  
Author(s):  
◽  
N. Aghanim ◽  
Y. Akrami ◽  
M. Ashdown ◽  
J. Aumont ◽  
...  
Keyword(s):  
Large Scale ◽  
Direct Evidence ◽  
Velocity Dispersion ◽  
Matched Filter ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Statistical Homogeneity ◽  
Cross Correlations

Using the Planck full-mission data, we present a detection of the temperature (and therefore velocity) dispersion due to the kinetic Sunyaev-Zeldovich (kSZ) effect from clusters of galaxies. To suppress the primary CMB and instrumental noise we derive a matched filter and then convolve it with the Planck foreground-cleaned “2D-ILC” maps. By using the Meta Catalogue of X-ray detected Clusters of galaxies (MCXC), we determine the normalized rms dispersion of the temperature fluctuations at the positions of clusters, finding that this shows excess variance compared with the noise expectation. We then build an unbiased statistical estimator of the signal, determining that the normalized mean temperature dispersion of 1526 clusters is 〈(ΔT/T)2 〉 = (1.64 ± 0.48) × 10−11. However, comparison with analytic calculations and simulations suggest that around 0.7 σ of this result is due to cluster lensing rather than the kSZ effect. By correcting this, the temperature dispersion is measured to be 〈(ΔT/T)2〉 = (1.35 ± 0.48) × 10−11, which gives a detection at the 2.8 σ level. We further convert uniform-weight temperature dispersion into a measurement of the line-of-sight velocity dispersion, by using estimates of the optical depth of each cluster (which introduces additional uncertainty into the estimate). We find that the velocity dispersion is 〈υ2〉 = (123 000 ± 71 000) (km s−1)2, which is consistent with findings from other large-scale structure studies, and provides direct evidence of statistical homogeneity on scales of 600 h−1 Mpc. Our study shows the promise of using cross-correlations of the kSZ effect with large-scale structure in order to constrain the growth of structure.

scholarly journals The All-Sky Extragalactic X-Ray Foreground

1990 ◽  
Vol 123 ◽  
pp. 451-455
Author(s):  
Elihu Boldt
Keyword(s):  
Active Galactic Nuclei ◽  
Large Scale ◽  
Local Group ◽  
Galactic Nuclei ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Local Space ◽  
Dipole Analysis ◽  
Statistical Sample ◽  
Compact Sources

Observations of galaxies in the IR and optical (Lynden-Bell et al. 1989) suggest that the 600 km/s peculiar velocity of the LG (Local Group of galaxies) arises mainly from a foreground of anisotropically distributed mass within z = 0.013 (i.e., HR < 4000 km/s). Since the X-ray luminosity of bright extragalactic X-ray sources provides a good mass measure of the radiating objects involved and can be observed relatively free of galactic obscuration effects, such sources are likely candidates for serving as reliable tracers of the total underlying mass (i.e., dark as well as visible) responsible for the acceleration of the LG. In this connection, we note that the local gravitational dipole implied by the fifty X-ray brightest clusters of galaxies at z > 0.013 considered by Lahav et al. (1989) is relatively small compared with that inferred from the only three clusters at lower redshifts. Since the local space density of AGN (Active Galactic Nuclei) is about two orders of magnitude greater than rich clusters, however, such compact sources have the potential of providing a vastly improved statistical sample for tracing mass in the low-redshift region of particular interest. Furthermore, recent dipole analysis of the X-ray flux from bright AGN observed with HEAO-1 A2 indicates that they are indeed strong tracers of this matter (Miyaji and Boldt 1990). The implications of this for the very pronounced large-scale foreground anisotropies to be measured via low-redshift AGN resolved in more sensitive all-sky surveys are explored.

scholarly journals The X-Ray Background: Origin and Implications

1980 ◽  
Vol 92 ◽  
pp. 207-225
Author(s):  
Martin J. Rees
Keyword(s):  
Large Scale ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
X Ray Background ◽  
The Universe

This paper will be concerned with three topics relevant to the X-ray background: (i) X-ray emission mechanisms in quasars; (ii) the contributions to the X-ray background from quasars, clusters of galaxies, intercluster gas, young galaxies, etc; and (iii) the use of X-ray background observations as a probe for large-scale density irregularities in the Universe.

scholarly journals Large-scale structure of X-ray clusters of galaxies

1979 ◽  
Vol 189 (2) ◽  
pp. 183-188 ◽  
Author(s):  
P. E. J. Nulsen ◽  
A. C. Fabian ◽  
R. F. Mushotzky ◽  
E. A. Boldt ◽  
S. S. Holt ◽  
...  
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
X Ray

scholarly journals Clusters of Galaxies in a Flat CHDM Universe

1998 ◽  
Vol 188 ◽  
pp. 299-299
Author(s):  
A. Habe ◽  
C. Hanyu ◽  
S. Yachi
Keyword(s):  
Dark Matter ◽  
Large Scale ◽  
Large Scale Structure ◽  
Numerical Results ◽  
Clusters Of Galaxies ◽  
Statistical Features ◽  
X Ray ◽  
Numerical Resolution ◽  
Radiative Processes ◽  
The Universe

Cold and hot dark matter (CHDM) model is one of viable models which can reproduce the large scale structure of the universe. HDM may affect structure of clusters of galaxies in CHDM universe. Bryan et al. (1994) gave numerical results of CHDM model that explain some statistical features of X-ray clusters of galaxies, e.g. X-ray luminosiry-temperature realtion, L ∝~ T3.5, without considering radiative processes. However their numerical resolution is insufficient to resolve the cores of X-ray clusters. So, we simulate the formation of clusters in CHDM universe more carefully.

scholarly journals X-Ray Probing of the Central Regions of Clusters of Galaxies

2001 ◽  
Vol 53 (3) ◽  
pp. 401-420 ◽  
Author(s):  
Kazuo Makishima ◽  
Hajime Ezawa ◽  
Yasushi Fukazawa ◽  
Hirohiko Honda ◽  
Yasushi Ikebe ◽  
...  
Keyword(s):  
Clusters Of Galaxies ◽  
X Ray ◽  
Central Regions

scholarly journals NEW RESULTS FROM H.E.S.S. OBSERVATIONS OF GALAXY CLUSTERS

2009 ◽  
Vol 18 (10) ◽  
pp. 1627-1631 ◽  
Author(s):  
◽  
WILFRIED DOMAINKO ◽  
DALIBOR NEDBAL ◽  
JAMES A. HINTON ◽  
OLIVIER MARTINEAU-HUYNH
Keyword(s):  
Cosmic Rays ◽  
Galaxy Clusters ◽  
Gamma Rays ◽  
Large Scale ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Model Predictions ◽  
The Universe

Clusters of galaxies are believed to contain a significant population of cosmic rays. From the radio and probably hard X-ray bands it is known that clusters are the spatially most extended emitters of non-thermal radiation in the Universe. Due to their content of cosmic rays, galaxy clusters are also potential sources of VHE (> 100 GeV) gamma rays. Recently, the massive, nearby cluster Abell 85 has been observed with the H.E.S.S. experiment in VHE gamma rays with a very deep exposure as part of an ongoing campaign. No significant gamma-ray signal has been found at the position of the cluster. The non-detection of this object with H.E.S.S. constrains the total energy of cosmic rays in this system. For a hard spectral index of the cosmic rays of -2.1 and if the cosmic-ray energy density follows the large scale gas density profile, the limit on the fraction of energy in these non-thermal particles with respect to the total thermal energy of the intra-cluster medium is 8% for this particular cluster. This value is at the lower bounds of model predictions.

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