scholarly journals An X-ray and Radio Study of the Hubble Frontier Field Cluster Abell S1063

2021 ◽  
Author(s):  
Majidul Rahaman ◽  
Ramij Raja ◽  
Abhirup Datta ◽  
Jack O Burns ◽  
Brian Alden ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
High Fidelity ◽  
Radio Flux ◽  
X Ray ◽  
Radio Halo ◽  
Average Temperature ◽  
North East ◽  
The North ◽  
Cluster Of Galaxies

Abstract We present results from Chandra X-ray observations and 325 MHz Giant Metrewave Radio Telescope (GMRT) observations of the massive and X-ray luminous cluster of galaxies Abell S1063. We report the detection of large-scale “excess brightness” in the residual Chandra X-ray surface brightness map, which extends at least 2.7 Mpc towards the north-east from the center of the cluster. We also present a high fidelity X-ray flux and temperature map using Chandra archival data of 122 ksec, which shows the disturbed morphology in the cluster. The residual flux map shows the first observational confirmation of the merging axis proposed in earlier simulations. The average temperature within R500 is 11.7 ± 0.56 keV, which makes AS1063 one of the hottest clusters in the nearby Universe. The integrated radio flux density at 325 MHz is found to be 62.0 ± 6.3 mJy. The integrated spectrum of the radio halo follows a power-law with a spectral index α = −1.43 ± 0.13. The radio halo is found to be significantly under-luminous, which favored for both the hadronic as well as the turbulent re-acceleration mechanism for its origin.

scholarly journals Employing Geographical Principles for Sampling in State of the Art Dialectological Projects

2013 ◽  
Vol 1 (2) ◽  
pp. 96-114 ◽  
Author(s):  
Isabelle Buchstaller ◽  
Seraphim Alvanides
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Pilot Project ◽  
Linguistic Analysis ◽  
Human Geography ◽  
North East ◽  
The North ◽  
Functional Regions ◽  
Demographic Classification

The aims of this paper are twofold. First, we locate the most effective human geographical methods for sampling across space in large-scale dialectological projects. We propose two geographical concepts as a basis for sampling decisions: Geo-demographic classification, which is a multidimensional method used for the socio-economic grouping of areas; we also develop an updated version of functional regions that can be used in sociolinguistic research. We then report on the results of a pilot project that applies these models to collect data regarding the acceptability of vernacular morphosyntactic forms in the North East of England. Following the method of natural breaks advocated for dialectology by Horvath & Horvath (2002), we interpret breaks in the probabilistic patterns as areas of dialect transitions. This study contributes to the debate about the role and limitations of spatiality in linguistic analysis. It intends to broaden our knowledge about the interfaces between human geography and dialectology.

scholarly journals Capitalismo distrettuale, localismi d'impresa, globalizzazione

2008 ◽  
Keyword(s):  
Industrial Development ◽  
Large Scale ◽  
International Markets ◽  
Scope Economies ◽  
North East ◽  
The North ◽  
Productive System ◽  
Dimensional Growth ◽  
It Revolution ◽  
Made In

From the late Sixties on, industrial development in Italy evolved through the spread of small and medium sized firms, aggregated in district networks, with an elevated propensity to enterprise and the marked presence of owner-families. Installed within the local systems, the industrial districts tended to simulate large-scale industry exploiting lower costs generated by factors that were not only economic. The districts are characterised in terms of territorial location (above all the thriving areas of the North-east and Centre) and sector, since they are concentrated in the "4 As" (clothing-fashion, home-decor, agri-foodstuffs, automation-mechanics), with some overlapping with "Made in Italy". How can this model be assessed? This is the crucial question in the debate on the condition and prospects of the Italian productive system between the supporters of its capacity to adapt and the critics of economic dwarfism. A dispassionate judgement suggests that the prospects of "small is beautiful" have been superseded, but that the "declinist" view, that sees only the dangers of globalisation and the IT revolution for our SMEs is risky. The concept of irreversible crisis that prevails at present is limiting, both because it is not easy either to "invent", or to copy, a model of industrialisation, and because there is space for a strategic repositioning of the district enterprises. The book develops considerations in this direction, showing how an evolution of the district model is possible, focusing on: gains in productivity, scope economies (through diversification and expansion of the range of products), flexibility of organisation, capacity to meld tradition and innovation aiming at product quality, dimensional growth of the enterprises, new forms of financing, active presence on the international markets and valorisation of the resources of the territory. It is hence necessary to reactivate the behavioural functions of the entrepreneurs.

scholarly journals The effect of the north-east ice stream on the Greenland ice sheet in changing climates

2007 ◽  
Vol 1 (1) ◽  
pp. 41-76 ◽  
Author(s):  
R. Greve ◽  
S. Otsu
Keyword(s):  
Large Scale ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Simulation Code ◽  
North East ◽  
The North ◽  
Ice Stream ◽  
Basal Sliding ◽  
Speed Up ◽  
Fast Flow

Abstract. The north-east Greenland ice stream (NEGIS) was discovered as a large fast-flow feature of the Greenland ice sheet by synthetic aperture radar (SAR) imaginary of the ERS-1 satellite. In this study, the NEGIS is implemented in the dynamic/thermodynamic, large-scale ice-sheet model SICOPOLIS (Simulation Code for POLythermal Ice Sheets). In the first step, we simulate the evolution of the ice sheet on a 10-km grid for the period from 250 ka ago until today, driven by a climatology reconstructed from a combination of present-day observations and GCM results for the past. We assume that the NEGIS area is characterized by enhanced basal sliding compared to the "normal", slowly-flowing areas of the ice sheet, and find that the misfit between simulated and observed ice thicknesses and surface velocities is minimized for a sliding enhancement by the factor three. In the second step, the consequences of the NEGIS, and also of surface-meltwater-induced acceleration of basal sliding, for the possible decay of the Greenland ice sheet in future warming climates are investigated. It is demonstrated that the ice sheet is generally very susceptible to global warming on time-scales of centuries and that surface-meltwater-induced acceleration of basal sliding can speed up the decay significantly, whereas the NEGIS is not likely to dynamically destabilize the ice sheet as a whole.

scholarly journals Alternatives to the Existence of Large Cooling Flows

1990 ◽  
Vol 115 ◽  
pp. 232-239
Author(s):  
Wallace Tucker
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
Theoretical Calculations ◽  
Central Peak ◽  
High Energy ◽  
Cooling Time ◽  
Radiative Cooling ◽  
Massive Black Hole ◽  
X Ray ◽  
Cooling Flows

AbstractArguments against the existence of large scale cooling flows in clusters of galaxies are presented. The evidence for cooling flows is all circumstantial, consisting of observations of cool gas or hot gas with a radiative cooling time less than the Hubble time, or a central peak in the x-ray surface brightness profile. There is no evidence for large quantities (several tens to several hundreds of solar masses per year) of matter actually flowing anywhere. On the contrary, several lines of evidence — stellar dynamics, observations of the amount of star formation, x-ray surface brightness observations, theoretical calculations of the growth of thermal instabilities, the amount of cold gas — suggest that cooling flows, if they exist, must be suppressed by one to two orders of magnitude from the values implied by simple estimates based on the radiative cooling time of the x-ray emitting gas. Two heat sources which might accomplish this — thermal conduction and relativistic particles, are considered and an alternative to the standard model for cooling flows is presented: an accretion flow with feedback wherein the accretion of gas into a massive black hole in the central galaxy generates high energy particles that heat the gas and act to limit the accretion.

scholarly journals Identification of a Complete Sample of Northern Rosat All-Sky Survey X-Ray Sources

1998 ◽  
Vol 179 ◽  
pp. 449-449
Author(s):  
J. Krautter ◽  
I. Thiering ◽  
F.-J Zickgraf ◽  
I. Appenzeller ◽  
R. Kneer ◽  
...  
Keyword(s):  
Optical Observations ◽  
Limited Sample ◽  
Ccd Imaging ◽  
X Ray ◽  
The North ◽  
Cluster Of Galaxies ◽  
Faint Object ◽  
Sky Survey ◽  
Faint Object Spectrograph ◽  
North Galactic

We present results of the optical identification of a spatially complete, flux limited sample of about 700 ROSAT All-Sky X-ray sources contained in 6 study areas north of δ = −9° with |bII|> 20° (including one region near the North Galactic pole (NGP), another one near the North Ecliptic pole (NEP)). Countrate limits are 0.01 cts s–1 near the NEP and 0.03 cts s–1 for the other areas. The optical observations were performed at the 2.15-m telescope of the Guillermo Haro Observatory, Mexico, using the Landessterwarte Faint Object Spectrograph Camera which allows to carry out direct CCD imaging and multi-object spectroscopy. The limiting magnitude is about 19m for spectroscopy and about 23m for B and R direct imaging. Our analysis shows a dependency of the ratio of ‘extragalactic’ (e.g., AGN, cluster of galaxies) to ‘stellar’ (e.g., coronal emitters, active binaries) counterparts on NH. In the area near the NGP (low NH) ‘extragalactic’ counterparts dominate, while in the area with the highest NH ‘stellar’ counterparts dominate.

scholarly journals The Ghosts of Galaxies: Tidal Debris in Clusters

2004 ◽  
Vol 217 ◽  
pp. 70-76
Author(s):  
Michael D. Gregg ◽  
Michael J. West
Keyword(s):  
Globular Clusters ◽  
Surface Brightness ◽  
Large Scale ◽  
Dwarf Galaxies ◽  
Cluster Formation ◽  
X Ray ◽  
Cluster Evolution ◽  
Low Surface Brightness ◽  
Intergalactic Space ◽  
Formation And Evolution

Gravitational interactions in rich clusters can strip material from the outer parts of galaxies or even completely disrupt entire systems, giving rise to large scale, low surface brightness ghostly features stretching across intergalactic space. The nearby Coma and Centaurus clusters both have striking examples of galaxy ghosts, in the form of 100 kpc-long plumes of intergalactic debris. By searching HST archival images, we have found numerous other examples of galaxy ghosts in rich clusters at low redshift, evidence that galaxy destruction and recycling are ubiquitous, important in cluster formation and evolution, and continue to mold clusters at the present epoch. Many ghosts appear in X-ray bright clusters, perhaps signaling a connection with energetic subcluster mergers.The fate of such material has important ramifications for cluster evolution. Our new HST WFPC2 V & I images of a portion of the Centaurus plume reveal that it contains an excess of discrete objects with −12 < MV < −6, consistent with being globular clusters or smaller dwarf galaxies. This tidally liberated material is being recycled directly into the intracluster population of stars, dwarf galaxies, globular clusters, and gas, which may have been built largely from a multitude of similar events over the life of the cluster.

scholarly journals The mergers in Abell 2256: displaced gas and its connection to the radio-emitting plasma

2020 ◽  
Vol 495 (4) ◽  
pp. 5014-5026 ◽  
Author(s):  
J P Breuer ◽  
N Werner ◽  
F Mernier ◽  
T Mroczkowski ◽  
A Simionescu ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
Cold Front ◽  
Low Frequency ◽  
Brightness Distribution ◽  
Analytical Models ◽  
Line Of Sight ◽  
Cluster Galaxy ◽  
X Ray ◽  
Low Entropy

ABSTRACT We present the results of deep Chandra and XMM–Newton X-ray imaging and spatially resolved spectroscopy of Abell 2256, a nearby (z = 0.058) galaxy cluster experiencing multiple mergers and displaying a rich radio morphology dominated by a large relic. The X-ray data reveal three subclusters: (i) the ‘main cluster’; (ii) the remnant of an older merger in the east of the cluster with an ∼600 kpc-long tail; (iii) a bright, bullet-like, low-entropy infalling system, with a large line-of-sight velocity component. The low-entropy system displays a 250 kpc-long cold front with a break and an intriguing surface brightness decrement. Interestingly, the infalling gas is not co-spatial with bright galaxies and the radio-loud brightest cluster galaxy of the infalling group appears dissociated from the low-entropy plasma by ∼50 kpc in projection, to the south of the eastern edge of the cold front. Assuming that the dark matter follows the galaxy distribution, we predict that it is also significantly offset from the low-entropy gas. Part of the low-frequency radio emission near the cold front might be revived by magnetic field amplification due to differential gas motions. Using analytical models and numerical simulations, we investigate the possibility that the supersonic infall of the subcluster generates a large-scale shock along our line of sight, which can be detected in the X-ray temperature map but is not associated with any clear features in the surface brightness distribution.

Large scale extended X-ray emission from the Virgo cluster of galaxies

Nature ◽  
1989 ◽  
Vol 340 (6231) ◽  
pp. 289-290 ◽  
Author(s):  
S. Takano ◽  
H. Awaki ◽  
K. Koyama ◽  
H. Kunieda ◽  
Y. Tawara ◽  
...  
Keyword(s):  
Large Scale ◽  
Virgo Cluster ◽  
X Ray ◽  
Cluster Of Galaxies

scholarly journals Numerically investigating the morphology of the supernova remnant SN 1006 in the ambient medium with a density discontinuity

2019 ◽  
Vol 491 (2) ◽  
pp. 2460-2464 ◽  
Author(s):  
Jun Fang ◽  
Jingwen Yan ◽  
Lu Wen ◽  
Chunyan Lu ◽  
Huan Yu
Keyword(s):  
Supernova Remnant ◽  
Ambient Medium ◽  
X Rays ◽  
X Ray ◽  
North West ◽  
Density Discontinuity ◽  
North East ◽  
The North ◽  
South West ◽  
Type Ia

ABSTRACT Multiband observations on the Type Ia supernova remnant SN 1006 indicate peculiar properties in its morphologies of emission in the radio, optical, and X-ray bands. In the hard X-rays, the remnant is bilateral with two opposite bright limbs with prominent protrusions. Moreover, a filament has been detected at the radio, optical, and soft X-ray wavelengths. The reason for these peculiar features in the morphologies of the remnant is investigated using 3D HD simulations. With the assumption that the supernova ejecta are evolved in the ambient medium with a density discontinuity, the radius of the remnant’s boundary is smaller in the tenuous medium, and the shell consists of two hemispheres with different radii. Along particular line of sights, protrusions appear on the periphery of the remnants since the emission from the edge of the hemisphere with a larger radius is located outside that from the shell of the small hemisphere. Furthermore, the north-west filament of SN 1006 arises as a result of the intersection of the line of sight and the shocked material near the edges of the two hemispheres. It can be concluded that the protrusions on the north-east and south-west limbs and the north-west filament in the morphologies of SN 1006 can be reproduced as the remnants interacting with the medium with a density discontinuity.

scholarly journals The Kinematic Structure of the Supergiant Shell LMC 2

1999 ◽  
Vol 190 ◽  
pp. 156-157
Author(s):  
Sean Points ◽  
You-Hua Chu ◽  
Sungeun Kim ◽  
Robert Gruendl ◽  
R. Chris Smith ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Large Magellanic Cloud ◽  
Kinematic Structure ◽  
Filamentary Structure ◽  
Star Formation Region ◽  
Formation Region ◽  
Active Star ◽  
X Ray ◽  
The North

LMC2 was one of the first supergiant shells in the Large Magellanic Cloud (LMC) to be identified, based on the detection of long, curved Hα filaments extending over 900 pc (Goudis & Meaburn 1978). LMC 2 is located to the east of the active star formation region south of 30 Doradus. LMC 2 is a spectacular supergiant shell in the LMC, having the most coherent filamentary structure and the highest X-ray surface brightness. As shown in Fig. 1, the diffuse X-ray emission from LMC 2 is bounded by the Hα filaments in the north and east. A bright X-ray arc is seen in the southwest quadrant, extending from N 158 and N 159.

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