scholarly journals Theoretical Implications of Diffuse Non-Thermal Emission from Clusters of Galaxies

2002 ◽  
Vol 199 ◽  
pp. 141-148
Author(s):  
T.A. Enßlin
Keyword(s):  
Thermal Emission ◽  
Extreme Ultraviolet ◽  
Short Review ◽  
Radio Galaxies ◽  
High Energy ◽  
Clusters Of Galaxies ◽  
Thermal Electron ◽  
Electron Population ◽  
X Ray

A short review on theoretical implications of non-thermal emission (radio, extreme ultraviolet, high energy X-ray) from the intra-cluster medium is given. The origin of cluster radio halos and cluster radio relics is discussed within the framework of a network of processes producing a non-thermal electron population. Emphasis is given to the role of old, remnant, presently invisible relativistic plasma released by former radio galaxies.

scholarly journals Evolution of MAXI J1631–479 during the January 2019 outburst observed by INTEGRAL/IBIS

2020 ◽  
Vol 492 (3) ◽  
pp. 3657-3661 ◽  
Author(s):  
M Fiocchi ◽  
F Onori ◽  
A Bazzano ◽  
A J Bird ◽  
A Bodaghee ◽  
...  
Keyword(s):  
Galactic Plane ◽  
Thermal Emission ◽  
Spectral Characteristics ◽  
Monitoring Program ◽  
High Energy ◽  
Thermal Electron ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Black Hole Candidate ◽  
Decay Times

ABSTRACT We report on a recent bright outburst from the new X-ray binary transient MAXI J1631–479, observed in January 2019. In particular, we present the 30–200 keV analysis of spectral transitions observed with INTEGRAL/IBIS during its Galactic plane monitoring program. In the MAXI and BAT monitoring period, we observed two different spectral transitions between the high/soft and low/hard states. The INTEGRAL spectrum from data taken soon before the second transition is best described by a Comptonized thermal component with a temperature of kTe ∼ 30 keV and a high-luminosity value of $L_{2-200\, \mathrm{keV}}\sim 3\times 10^{38}$ erg−1 (assuming a distance of 8 kpc). During the second transition, the source shows a hard, power-law spectrum. The lack of high energy cut-off indicates that the hard X-ray spectrum from MAXI J1631–479 is due to a non-thermal emission. Inverse Compton scattering of soft X-ray photons from a non-thermal or hybrid thermal/non-thermal electron distribution can explain the observed X-ray spectrum although a contribution to the hard X-ray emission from a jet cannot be determined at this stage. The outburst evolution in the hardness-intensity diagram, the spectral characteristics, and the rise and decay times of the outburst are suggesting that this system is a black hole candidate.

Steep-Spectrum Radio Sources in Clusters of Galaxies—The Southern Sample

1984 ◽  
Vol 5 (4) ◽  
pp. 516-529 ◽  
Author(s):  
O. B. Slee ◽  
J. E. Reynolds
Keyword(s):  
Radio Galaxies ◽  
High Energy ◽  
Radio Spectrum ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Detailed Review ◽  
X Ray ◽  
High Energy Electrons ◽  
Spectrum Radio ◽  
Inverse Compton

It is well established (e.g. Slee et al. 1983) that radio galaxies near the centres of rich clusters of galaxies tend to have steeper radio spectra than field radio galaxies. The fact that the sources with the steepest spectra occur in clusters that are highly luminous X-ray emitters has generally been interpreted in terms of the confining influence of a hot (~108 K), relatively dense (10-2 to 10-3 electrons cm-3) intra-cluster gas; the confined relativistic plasma then preferentially loses its high-energy electrons through synchrotron and inverse Compton losses, resulting in a steepening of the radio spectrum. A more detailed review of the evidence for this process is given by Robertson (1983).

A possible heating mechanism for the X-ray-emitting plasma within clusters of galaxies

2013 ◽  
Vol 79 (4) ◽  
pp. 447-450
Author(s):  
R. BINGHAM ◽  
B. J. KELLETT ◽  
U. DE ANGELIS ◽  
V. N. TSYTOVICH ◽  
P. K. SHUKLA
Keyword(s):  
Thermal Emission ◽  
Extreme Ultraviolet ◽  
Energy Content ◽  
Self Organization ◽  
Clusters Of Galaxies ◽  
Ultraviolet Emission ◽  
X Ray ◽  
Heating Mechanism ◽  
Hot Plasma ◽  
Thermal Energy Content

AbstractX-ray and extreme ultraviolet emission from galaxy clusters can be interpreted as thermal emission from a hot plasma gravitationally bound to the cluster and constituting a significant amount of the mass of the cluster. The origin of this plasma and its thermal energy content can be linked to the formation process through the theory of self-organization of these structures.

The Role of the Coelomic Fluid in the Movements of Earthworms

1950 ◽  
Vol 27 (1) ◽  
pp. 110-122 ◽  
Author(s):  
G. E. NEWELL
Keyword(s):  
Short Review ◽  
The Body ◽  
Coelomic Fluid ◽  
Average Pressure ◽  
Normal Range ◽  
Tail Region ◽  
X Ray ◽  
Effective Barrier ◽  
Intrinsic Muscles

1. A short review is given of the coelom and of its morphological relations in the earthworm. 2. The arrangement of the intrinsic muscles in a typical septum is described. Four main sets of muscles are recognized: viz. radial muscles, circular muscles, oblique muscles, and the sphincter around the ventral foramen. 3. It is suggested that the function of the radial, circular and possibly of the oblique muscles is to control bulging of the septa, and so serve to localize differences in pressure in the coelomic fluid. Normally, in active worms, the sphincter of the ventral foramen is contracted and forms an effective barrier to the passage of fluid from one coelomic compartment to the next. This was verified experimentally and by X-ray photography. 4. A series of measurements of the pressure in the coelomic fluid in different regions of active worms was recorded by means of a capillary manometer and by the use of a spoon-gauge apparatus. Manometric measurements showed the average pressure in the anterior third of the body to be 16.0 cm. water and in the tail region to be 8.0 cm. water. The corresponding figures obtained with a spoon gauge were 13.5 and 8.5 cm. water. The pressure in narcotized worms is zero. 5. These results are discussed, and it is pointed out that the manometer readings suffer from the disadvantage of failing to show the rapid fluctuations in pressure which occur during wriggling movements of the worms. 6. It is calculated from these pressure readings that a worm can exert a forward thrust equivalent to forces of between 1.5 and 8.0 g. These figures agree well with those obtained by Gray & Lissman by the use of a special torsion balance. 7. The burrowing movements of earthworms are briefly described. 8. It is shown that the sphincters of the dorsal pores and of the nephridiopores do not normally allow of the escape of coelomic fluid, and will withstand a pressure well outside the normal range.

scholarly journals The extreme ultraviolet and X-ray Sun in Time: High-energy evolutionary tracks of a solar-like star

2015 ◽  
Vol 577 ◽  
pp. L3 ◽  
Author(s):  
Lin Tu ◽  
Colin P. Johnstone ◽  
Manuel Güdel ◽  
Helmut Lammer
Keyword(s):  
Extreme Ultraviolet ◽  
High Energy ◽  
X Ray

Notizen: Zum Verständnis der zentralen Rolle des Schwefels in Multi-Metall-Aggregaten mit verschiedener Elektronenpopulation: [S2WS2CoS2WS2]n- (n = 2, 3)/On the Central Role of Sulfur in Multi Metal Aggregates with Different Electron Populations: [S2WS2CoS2WS2]n-(n = 2, 3)

1983 ◽  
Vol 38 (4) ◽  
pp. 528-529 ◽  
Author(s):  
Achim Müller ◽  
Winfried Hellmann ◽  
Uwe Schimanski ◽  
Rainer Jostes ◽  
William E. Newton
Keyword(s):  
Structure Analysis ◽  
Electron Population ◽  
X Ray ◽  
Ligand System ◽  
Physical Measurements ◽  
Theoretical Investigations ◽  
Additional Charge ◽  
Metal Ligand

Abstract The hetero metal sulfur aggregates [Co(WS4)2] n- (with variable electron population: n = 2, 3) could be isolated as salts and characterized by physical measurements (in-cluding X-ray structure analysis). Experimental and theoretical investigations show that due to a strong metal → ligand electron delocalisation WS42-(like MOS42-) is a non-innocent ligand and that the additional charge upon reduction is located mainly at the S atoms of the ligand system.

Commission N°48: High Energy Astrophysics (Astrophysique Des Hautes Energies)

1988 ◽  
Vol 20 (1) ◽  
pp. 671-675
Author(s):  
C.J. Cesarsky ◽  
R.A. Sunyaev ◽  
G.W. Clark ◽  
R. Giacconi ◽  
Vin-Yue Qu ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Supernova Remnants ◽  
Cataclysmic Variables ◽  
Galactic Nuclei ◽  
High Energy ◽  
Clusters Of Galaxies ◽  
High Energy Astrophysics ◽  
X Ray ◽  
X Ray Binaries ◽  
Imaging Telescopes

The european X-ray observatory (EXOSAT), which was launched in 1983 and which finished operations in April 1986, has brought a rich harvest of results in the period 1984-1987, surveyed here. The EXOSAT payload consisted of three sets of instruments: two low energy imaging telescopes (LE:E<2 KeV), a medium-energy experiment (ME:E=l-50KeV) and a gas scintillation proportional counter (GSPC:E=2-20KeV). Over most of the energy range covered, EXOSAT was not more sensitive than its predecessor, the american EINSTEIN satellite. But the EINSTEIN satellite is far from having exhausted the treasures of the X-ray sky. And EXOSAT, thanks to its elliptical 90-hour orbit, had the extra advantage of being able to make long, continuous observations of interesting objects, lasting up to 72 hours. Thus, EXOSAT was very well suited for variability studies, and many of its most important findings are in this area. EXOSAT observations sample a vide range of astrophysical sources: X-ray binaries, cataclysmic variables and active stars; supernova remnants and the interstellar medium; active galactic nuclei, and clusters of galaxies. Among the highlights, let us mention:

Photoionized plasmas induced in neon with extreme ultraviolet and soft X-ray pulses produced using low and high energy laser systems

2015 ◽  
Vol 22 (4) ◽  
pp. 043302 ◽  
Author(s):  
A. Bartnik ◽  
P. Wachulak ◽  
T. Fok ◽  
Ł. Węgrzyński ◽  
H. Fiedorowicz ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
High Energy ◽  
X Ray ◽  
Laser Systems ◽  
Energy Laser ◽  
High Energy Laser ◽  
Photoionized Plasmas

scholarly journals The Role of Wide Field X-ray Surveys in Astronomy

2012 ◽  
Vol 10 (H16) ◽  
pp. 669-670
Author(s):  
Richard D. Saxton
Keyword(s):  
High Variability ◽  
Wide Field ◽  
Clusters Of Galaxies ◽  
Tidal Disruption ◽  
X Ray ◽  
Sky Survey ◽  
History Of ◽  
X Ray Background ◽  
Rare Classes

AbstractWe review the history of X-ray sky surveys from the early experiments to the catalogues of 105 sources produced by ROSAT, Chandra and XMM-Newton. At bright fluxes the X-ray sky is shared between stars, accreting binaries and extragalactic sources while deeper surveys are dominated by AGN and clusters of galaxies. The X-ray background, found by the earliest missions, has been largely resolved into discrete sources at soft (0.3-2 keV) energies but at higher energies an important fraction still escapes detection. The possible identification of the missing flux with Compton-thick AGN has been probed in recent years by Swift and Integral.Variability seen in objects observed at different epochs has proved to be an excellent discriminator for rare classes of objects. The comparison of ROSAT All Sky Survey (RASS) and ROSAT pointed observations identified several Novae and high variability AGN as well as initiating the observational study of Tidal Disruption events. More recently the XMM-Newton slew survey, in conjunction with archival RASS data, has detected further examples of flaring objects which have been followed-up in near-real time at other wavelengths.

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