scholarly journals X-Ray and Radio Emissions of AWM and MKW Clusters

Author(s):  
Michael Ramuta

A grasp of the life-cycles of large-scale structures is critical to understanding the Universe. This can be accomplished through the study of poor clusters-- that is, younger clusters that are likely evolving to another state. The selected clusters are significant in that they are poor but also possess a type-cD galaxy. This brighter central galaxy suggests that these clusters may be dynamically evolved and are potential candidates for fossil groups. In order to more fully understand the structure and behavior of poor galaxy clusters, 12 clusters were selected and analyzed. Using data from the Sloan Digital Sky Survey, Chandra X-Ray Archive, and the VLA FIRST Survey, we present x-ray profiles and radio observations of these 12 galaxy clusters. 

2014 ◽  
Vol 11 (S308) ◽  
pp. 299-300
Author(s):  
Shishir Sankhyayan ◽  
J. Bagchi ◽  
P. Sarkar ◽  
V. Sahni ◽  
J. Jacob

AbstractWe have initiated the search and detailed study of large scale structures present in the universe using galaxy redshift surveys. In this process, we take the volume-limited sample of galaxies from Sloan Digital Sky Survey III and find very large structures even beyond the redshift of 0.2. One of the structures is even greater than 600 Mpc which raises a question on the homogeneity scale of the universe. The shapes of voids-structures (adjacent to each other) seem to be correlated, which supports the physical existence of the observed structures. The other observational supports include galaxy clusters' and QSO distribution's correlation with the density peaks of the volume limited sample of galaxies.


2006 ◽  
Vol 6 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Xin-Fa Deng ◽  
Yi-Qing Chen ◽  
Qun Zhang ◽  
Ji-Zhou He

Author(s):  
Ting-Wen Lan ◽  
J Xavier Prochaska

Abstract We test the hypothesis that environments play a key role in enabling the growth of enormous radio structures spanning more than 700 kpc, an extreme population of radio galaxies called giant radio galaxies (GRGs). To achieve this, we explore (1) the relationships between the occurrence of GRGs and the surface number density of surrounding galaxies, including satellite galaxies and galaxies from neighboring halos, as well as (2) the GRG locations towards large-scale structures. The analysis is done by making use of a homogeneous sample of 110 GRGs detected from the LOFAR Two-metre Sky Survey in combination with photometric galaxies from the DESI Legacy Imaging Surveys and a large-scale filament catalog from the Sloan Digital Sky Survey. Our results show that the properties of galaxies around GRGs are similar with that around the two control samples, consisting of galaxies with optical colors and luminosity matched to the properties of the GRG host galaxies. Additionally, the properties of surrounding galaxies depend on neither their relative positions to the radio jet/lobe structures nor the sizes of GRGs. We also find that the locations of GRGs and the control samples with respect to the nearby large-scale structures are consistent with each other. These results demonstrate that there is no correlation between the GRG properties and their environments traced by stars, indicating that external galaxy environments are not the primary cause of the large sizes of the radio structures. Finally, regarding radio feedback, we show that the fraction of blue satellites does not correlate with the GRG properties, suggesting that the current epoch of radio jets have minimal influence on the nature of their surrounding galaxies.


1988 ◽  
Vol 130 ◽  
pp. 540-540
Author(s):  
Ruth A. Daly

The diffuse x-ray background extends from about five to 200 keV. The spectrum is very well fit by a thermal bremsstrahlung emission spectrum characterized by a temperature of about (25–40)(l+z) keV, where z is the redshift at which the emission is produced.


2018 ◽  
Vol 619 ◽  
pp. A24 ◽  
Author(s):  
Valeria Mesa ◽  
Fernanda Duplancic ◽  
Sol Alonso ◽  
Maria Rosa Muñoz Jofré ◽  
Georgina Coldwell ◽  
...  

Aims. With the aim of performing an analysis of the orientations of galaxy pair systems with respect to the underlying large-scale structure, we study the alignment between the axis connecting the pair galaxies and the host cosmic filament where the pair resides. In addition, we analyze the dependence of the amplitude of the alignment on the morphology of pair members as well as filament properties. Methods. We build a galaxy pair catalog requiring rp < 100 h−1 kpc and ΔV < 500 km s−1 within redshift z < 0.1 from the Sloan Digital Sky Survey (SDSS). We divided the galaxy pair catalog taking into account the morphological classification by defining three pair categories composed by elliptical–elliptical (E–E), elliptical–spiral (E–S) and spiral–spiral (S–S) galaxies. We use a previously defined catalog of filaments obtained from SDSS and we select pairs located closer than 1 h−1 Mpc to the filament spine, which are considered as members of filaments. For these pairs, we calculate the relative angle between the axis connecting each galaxy, and the direction defined by the spine of the parent filament. Results. We find a statistically significant alignment signal between the pair axes and the spine of the host filaments consistent with a relative excess of ∼15% aligned pairs. We obtain that pairs composed by elliptical galaxies exhibit a stronger alignment, showing a higher alignment signal for pairs closer than 200 h−1 kpc to the filament spine. In addition, we find that the aligned pairs are associated with luminous host filaments populated with a high fraction of elliptical galaxies. The findings of this work show that large-scale structures play a fundamental role in driving galactic anisotropic accretion as induced by galaxy pairs exhibiting a preferred alignment along the filament direction.


1987 ◽  
Vol 124 ◽  
pp. 335-348
Author(s):  
Neta A. Bahcall

The evidence for the existence of very large scale structures, ∼ 100h−1Mpc in size, as derived from the spatial distribution of clusters of galaxies is summarized. Detection of a ∼ 2000 kms−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−1Mpc 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.


2019 ◽  
Vol 627 ◽  
pp. A5 ◽  
Author(s):  
F. Vazza ◽  
S. Ettori ◽  
M. Roncarelli ◽  
M. Angelinelli ◽  
M. Brüggen ◽  
...  

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.


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