scholarly journals Evidence for AGN Feedback in Galaxy Clusters and Groups

2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Myriam Gitti ◽  
Fabrizio Brighenti ◽  
Brian R. McNamara
Keyword(s):  
Galaxy Clusters ◽  
Galaxy Evolution ◽  
Large Scale ◽  
Current Knowledge ◽  
Dynamical Evolution ◽  
Large Scale Structures ◽  
Hot Gas ◽  
History Of ◽  
Initial Idea ◽  
Scale Structures

The current generation of flagship X-ray missions,ChandraandXMM-Newton, has changed our understanding of the so-called “cool-core” galaxy clusters and groups. Instead of the initial idea that the thermal gas is cooling and flowing toward the center, the new picture envisages a complex dynamical evolution of the intracluster medium (ICM) regulated by the radiative cooling and the nongravitational heating from the active galactic nucleus (AGN). Understanding the physics of the hot gas and its interplay with the relativistic plasma ejected by the AGN is key for understanding the growth and evolution of galaxies and their central black holes, the history of star formation, and the formation of large-scale structures. It has thus become clear that the feedback from the central black hole must be taken into account in any model of galaxy evolution. In this paper, we draw a qualitative picture of the current knowledge of the effects of the AGN feedback on the ICM by summarizing the recent results in this field.

scholarly journals Deep learning for Sunyaev–Zel’dovich detection in Planck

2020 ◽  
Vol 634 ◽  
pp. A81
Author(s):  
V. Bonjean
Keyword(s):  
Deep Learning ◽  
Galaxy Clusters ◽  
Large Scale ◽  
Galaxy Cluster ◽  
Proof Of Concept ◽  
Microwave Background ◽  
Large Scale Structures ◽  
Hot Gas ◽  
Scale Structures ◽  
The Universe

The Planck collaboration has extensively used the six Planck HFI frequency maps to detect the Sunyaev–Zel’dovich (SZ) effect with dedicated methods, for example by applying (i) component separation to construct a full-sky map of the y parameter or (ii) matched multi-filters to detect galaxy clusters via their hot gas. Although powerful, these methods may still introduce biases in the detection of the sources or in the reconstruction of the SZ signal due to prior knowledge (e.g. the use of the generalised Navarro, Frenk, and White profile model as a proxy for the shape of galaxy clusters, which is accurate on average but not for individual clusters). In this study, we use deep learning algorithms, more specifically, a U-net architecture network, to detect the SZ signal from the Planck HFI frequency maps. The U-net shows very good performance, recovering the Planck clusters in a test area. In the full sky, Planck clusters are also recovered, together with more than 18 000 other potential SZ sources for which we have statistical indications of galaxy cluster signatures, by stacking at their positions several full-sky maps at different wavelengths (i.e. the cosmic microwave background lensing map from Planck, maps of galaxy over-densities, and the ROSAT X-ray map). The diffuse SZ emission is also recovered around known large-scale structures such as Shapley, A399–A401, Coma, and Leo. Results shown in this proof-of-concept study are promising for potential future detection of galaxy clusters with low SZ pressure with this kind of approach, and more generally, for potential identification and characterisation of large-scale structures of the Universe via their hot gas.

scholarly journals Detecting shocked intergalactic gas with X-ray and radio observations

2019 ◽  
Vol 627 ◽  
pp. A5 ◽  
Author(s):  
F. Vazza ◽  
S. Ettori ◽  
M. Roncarelli ◽  
M. Angelinelli ◽  
M. Brüggen ◽  
...  
Keyword(s):  
Large Scale ◽  
Intergalactic Medium ◽  
Thermal Emission ◽  
Intergalactic Gas ◽  
Radio Observations ◽  
X Ray ◽  
Large Scale Structures ◽  
Hot Gas ◽  
Scale Structures ◽  
Radio Band

Detecting the thermal and non-thermal emission from the shocked cosmic gas surrounding large-scale structures represents a challenge for observations, as well as a unique window into the physics of the warm-hot intergalactic medium. In this work, we present synthetic radio and X-ray surveys of large cosmological simulations in order to assess the chances of jointly detecting the cosmic web in both frequency ranges. We then propose best observing strategies tailored for existing (LOFAR, MWA, and XMM) or future instruments (SKA-LOW and SKA-MID, Athena, and eROSITA). We find that the most promising targets are the extreme peripheries of galaxy clusters in an early merging stage, where the merger causes the fast compression of warm-hot gas onto the virial region. By taking advantage of a detection in the radio band, future deep X-ray observations will probe this gas in emission, and help us to study plasma conditions in the dynamic warm-hot intergalactic medium with unprecedented detail.

DENSITY PERTURBATIONS BY GLOBAL TEXTURES

1992 ◽  
Vol 01 (02) ◽  
pp. 427-437 ◽  
Author(s):  
MICHIYASU NAGASAWA ◽  
KATSUHIKO SATO
Keyword(s):  
Clustering Analysis ◽  
Large Scale ◽  
Dynamical Evolution ◽  
Conformal Time ◽  
Large Scale Structures ◽  
Cosmic Expansion ◽  
Density Perturbations ◽  
Scale Structures ◽  
Non Gaussian ◽  
The Universe

The dynamical evolution of global textures is studied. The evolution equation of a texture field is solved numerically and the effect of cosmic expansion is explicitly introduced. The process of knot collapse is traced and the knot number at conformal time, τ, per comoving volume is 0.01~0.02/τ3. The density perturbations by textures are investigated by a clustering analysis. High density clusters have large-scale correlation and extend widely, which enables the formation of large-scale structures. Moreover, the initial fluctuations by textures show the highly non-Gaussian spatial distribution. Thus they produce the density perturbations which may yield the cosmological structures in the universe.

scholarly journals Filament profiles from WISExSCOS galaxies as probes of the impact of environmental effects

2020 ◽  
Vol 638 ◽  
pp. A75 ◽  
Author(s):  
V. Bonjean ◽  
N. Aghanim ◽  
M. Douspis ◽  
N. Malavasi ◽  
H. Tanimura
Keyword(s):  
Galaxy Evolution ◽  
Large Scale ◽  
Value Added ◽  
Gas Content ◽  
Large Scale Structures ◽  
A Value ◽  
The Galaxy ◽  
Scale Structures ◽  
Isothermal Gas ◽  
The Impact

The role played by large-scale structures in galaxy evolution is not very well understood yet. In this study, we investigated properties of galaxies in the range 0.1 <  z <  0.3 from a value-added version of the WISExSCOS catalogue around cosmic filaments detected with DisPerSE. We fitted a profile of galaxy over-density around cosmic filaments and found a typical radius of rm = 7.5 ± 0.2 Mpc. We measured an excess of passive galaxies near to the spine of the filament that was higher than the excess of transitioning and active galaxies. We also detected star formation rates (SFR) and stellar mass (M⋆) gradients pointing towards the spine of the filament. We investigated this result and found an M⋆ gradient for each type of galaxy, that is active, transitioning, and passive; we found a positive SFR gradient for passive galaxies. We also linked the galaxy properties and gas content in the cosmic web. To do so, we investigated the quiescent fraction fQ profile of galaxies around the cosmic filaments. Based on recent studies about the effect of the gas and the cosmic web on galaxy properties, we modelled fQ with a β model of gas pressure. The slope obtained in this work, β = 0.54 ± 0.18, is compatible with the scenario of projected isothermal gas in hydrostatic equilibrium (β = 2/3) and with the profiles of gas fitted in Sunyaev-Zel’dovich data from the Planck satellite.

scholarly journals Multi-Frequency Study of the SZ Effect in Cosmic Structures

2014 ◽  
Vol 1 (1) ◽  
pp. 56-65
Author(s):  
Sergio Colafrancesco
Keyword(s):  
Galaxy Clusters ◽  
Large Scale ◽  
Future Directions ◽  
Large Scale Structures ◽  
Sunyaev Zel'dovich Effect ◽  
Scale Structures

The Sunyaev-Zel’dovich effect (SZE) is a relevant probe for cosmology and astrophysics. A multi-frequency approach to study the SZE in cosmic structures turns out to be crucial in the use of this probe for astrophysics and cosmology. Astrophysical and cosmological applications to galaxy clusters, galaxies, radiogalaxies and large-scale structures are discussed. Future directions for the study of the SZE and its polarization are finally outlined.

scholarly journals The Hunt for Primordial Interactions in the Large-Scale Structures of the Universe

Galaxies ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 71 ◽  
Author(s):  
Matteo Biagetti
Keyword(s):  
Large Scale ◽  
Current Knowledge ◽  
Accelerated Expansion ◽  
Late Time ◽  
Dark Matter Halos ◽  
Large Scale Structures ◽  
Time Correlations ◽  
Scale Structures ◽  
Consistent Treatment ◽  
The Universe

The understanding of the primordial mechanism that seeded the cosmic structures we observe today in the sky is one of the major goals in cosmology. The leading paradigm for such a mechanism is provided by the inflationary scenario, a period of violent accelerated expansion in the very early stages of evolution of the universe. While our current knowledge of the physics of inflation is limited to phenomenological models which fit observations, an exquisite understanding of the particle content and interactions taking place during inflation would provide breakthroughs in our understanding of fundamental physics at high energies. In this review, we summarize recent theoretical progress in the modeling of the imprint of primordial interactions in the large-scale structures of the universe. We focus specifically on the effects of such interactions on the statistical distribution of dark-matter halos, providing a consistent treatment of the steps required to connect the correlations generated among fields during inflation all the way to the late-time correlations of halos.

NON-THERMAL PHENOMENA IN GALAXY CLUSTERS

2012 ◽  
Vol 12 ◽  
pp. 280-289
Author(s):  
CHIARA FERRARI
Keyword(s):  
Galaxy Clusters ◽  
Large Scale ◽  
Thermal Component ◽  
X Ray ◽  
Large Scale Structures ◽  
Weak Magnetic Fields ◽  
Scale Structures ◽  
Thermal Phenomena ◽  
New Generation

The existence of cosmic rays and weak magnetic fields in the intracluster volume has been well proven by deep radio observations of galaxy clusters. However a detailed physical characterization of the non-thermal component of large scale-structures, relevant for high-precision cosmology, is still missing. I will show the importance of combining numerical and theoretical works with cluster observations by a new-generation of radio, Gamma- and X-ray instruments.

scholarly journals Superclustering and Motion of Galaxy Clusters*

1988 ◽  
Vol 130 ◽  
pp. 229-238
Author(s):  
Neta A. Bahcall
Keyword(s):  
Dark Matter ◽  
Spatial Distribution ◽  
Shell Model ◽  
Galaxy Clusters ◽  
Large Scale ◽  
Clusters Of Galaxies ◽  
Large Scale Structures ◽  
Peculiar Velocities ◽  
Scale Structures ◽  
Shell Intersections

The evidence for the existence of very large scale structures, ∼ 100h−1 Mpc in size, as derived from the spatial distribution of clusters of galaxies is summarized. A “shell model” of galaxy clustering is described in which clusters of galaxies are located at shell intersections; the model yields results consistent with cluster observations. Detection of a ∼ 2000 km s−1 elongation in the redshift direction in the distribution of the clusters is also described. Possible causes of the effect are peculiar velocities of clusters on scales of 10–100h−1 Mpc and geometrical elongation of superclusters. If the effect is entirely due to the peculiar velocities of clusters, then superclusters have masses of order 1016,5M⊙ and may contain a larger amount of dark matter than previously anticipated.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

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