scholarly journals Does the Magnetodynamic Model for the Formation of AGN Jets Survive New Findings of High-energy Phenomena near the Central Objects?

2000 ◽  
Vol 195 ◽  
pp. 473-481
Author(s):  
Y. Uchida
Keyword(s):  
Lorentz Factor ◽  
High Energy ◽  
Major Effect ◽  
Alfven Wave ◽  
Poynting Flux ◽  
Central Engine ◽  
New Findings ◽  
Wave Trains ◽  
Kink Instability ◽  
Jet Structure

Here, we argue that, despite all-new findings of phenomena with very large Lorentz factors, the importance of the magnetodynamic process accelerating and collimating AGN jets should not be affected because there exists evidence in the features of the jets and tails at large distances indicating that the wiggles of the jet structure are likely to be due to a magnetic, helical kink instability. These systematic features require too much energy and coherence of the driving process to be produced locally and axe most naturally produced by a magnetic effect coming from the powerful central engine. This indicates that the major effect producing the jets, and the lobes with hotspots at the tips of the jets, is likely to be the Poynting flux carried by torsional Alfvén wave trains plus the re-accelerated high-energy particles in them. The very large Lorentz-factor phenomena should not hinder the transfer of these magnetic effects and are likely to be byproducts of the basic magnetodynamic process, and not the reverse.

scholarly journals CTA 102 in exceptionally high state during 2016–2017

2018 ◽  
Vol 617 ◽  
pp. A59 ◽  
Author(s):  
Navpreet Kaur ◽  
Kiran S. Baliyan
Keyword(s):  
High Energy ◽  
High Energy Particle ◽  
Electromagnetic Spectrum ◽  
Energy Bands ◽  
Spectral Behavior ◽  
Flux Enhancement ◽  
Central Engine ◽  
Long Timescales ◽  
Jet Structure

Blazars in outburst provide a unique opportunity to study their spectral behavior, correlated variations at different frequencies, and jet structure. An unprecedented flaring activity in FSRQ CTA 102, occuring from 2016 November to 2017 January, is used here for a detailed study to understand flaring mechanisms at short and long timescales, spectral behavior in different energy regimes, and to estimate sizes and location of the high-energy emitting region in the jet. Multiwavelength (MW) data for CTA 102 during its outburst period, were obtained from Fermi-LAT, Swift-XRT/UVOT, Steward Observatory, Mt Abu Infrared Observatory, and OVRO. These were analyzed to construct MW light curves, extract the spectral information, and to perform the correlated variability studies. Our study shows that CTA 102 attained the highest ever flux levels across the electromagnetic spectrum (EMS) while flaring and otherwise, with rapid and prolonged activities at all the frequencies. A number of short-term (three to eight days) and long-term (more than a month) variability events are noticed across the EMS. We infer a redder when brighter trend in faint state and a bluer when brighter trend during a few optical flares. Based on the flux doubling timescale, the size of γ-ray emitting region is estimated as ≈8.76 × 1015 cm, located at a distance of about 5.58 × 1016 cm from the central engine. CTA 102 was in extremely bright phase during 2016–2017, possibly due to, successive high energy particle injections into the jet, creating shocks traveling down the jet which lead to the overall flux enhancement across the EMS. Alternatively, a decreasing viewing angle could also lead to such flux enhancement. The study reveals correlated variations in all the energy bands, with lags within time bins, indicating co-spatial origin of the emissions. During the flaring event, a bluer-when-brighter color in the optical and harder when brighter trend in the X-ray and γ-ray spectra are noticed. During some flares softer γ-ray spectra are observed.

scholarly journals Waves in Poynting-flux dominated jets

2010 ◽  
Vol 6 (S275) ◽  
pp. 77-81
Author(s):  
John G. Kirk ◽  
Iwona Mochol
Keyword(s):  
Black Hole ◽  
Lorentz Factor ◽  
High Energy ◽  
Acceleration Phase ◽  
Gravitational Radius ◽  
Rapid Variability ◽  
Poynting Flux ◽  
Electromagnetic Cascade ◽  
Relativistic Jet ◽  
High Energy Emission

AbstractHigh-energy emission from blazars is thought to arise in a relativistic jet launched by a supermassive black hole. The rapid variability of the emission suggests that structure of length scale smaller than the gravitational radius of the central black hole is imprinted on the jet as it is launched, and modulates the radiation released after it has been accelerated to high Lorentz factor. We describe a mechanism which can account for the acceleration of the jet, and for the rapid variability of the radiation, based on the propagation characteristics of nonlinear waves in charge-starved, polar jets. These exhibit a delayed acceleration phase, that kicks-in when the inertia associated with the wave currents becomes important. The time structure imprinted on the jet at launch modulates the photons produced by the accelerating jet provided that the electromagnetic cascade in the black-hole magnetosphere is not prolific.

Geomagnetic response to large-amplitude interplanetary Alfvén wave trains

1995 ◽  
Vol T60 ◽  
pp. 140-143 ◽  
Author(s):  
W D Gonzalez ◽  
A L Clúa de Gonzalez ◽  
B T Tsurutani
Keyword(s):  
Large Amplitude ◽  
Alfven Wave ◽  
Wave Trains

Fresh State Behaviour of Cement Paste Containing Nano Kaolin

2014 ◽  
Vol 925 ◽  
pp. 28-32 ◽  
Author(s):  
Muhd Sidek Muhd Norhasri ◽  
M.S. Hamidah ◽  
A. Mohd Fadzil ◽  
A.G. Abd Halim ◽  
M.R. Zaidi
Keyword(s):  
Surface Area ◽  
Cement Paste ◽  
Setting Time ◽  
High Energy ◽  
Major Effect ◽  
Cement Replacement ◽  
High Energy Milling ◽  
Replacement Method ◽  
Fresh State ◽  
State Behaviour

The application of nanomaterials in cement by replacement method in concrete is becoming a trend in cement research. The utilisation of nanosilica, nanoalumina, titanium oxide and others are proven to enhance properties of concrete. The major effect of nanomaterials is its size in which it contributes to the packing theory due to increase in the surface area. nanokaolin which comes from kaolin, was tansformed to the nanoform by using high energy milling. The process of developing nanokaolin by using high energy milling is referred to process top to bottom approach in nanoprocessing technique. In this research, the nanokaolin will be used as an additive in cement by 7% weight of cement. Four (4) cement replacement materials catered by using metakaolin on weight basis from 0, 10%, 20% and 30% will also be adopted. To determine the fresh state, cement paste contains nanokaolin and metakaolin are tested its standard consistency and setting time. The effect of the inclusion of the nanokaolin as additive in cement paste that also contains metakaolin as cement replacement material will be investigated. It was found the inclusion of 7% nanokaolin increases the water demand of the cement paste level of metakaolin replacement. In addition to that, the setting time namely initial and final set was been delayed as compared to that of plain OPC. The nanoparticles of nanokaolin and also finer particles of metakaolin increase the surface area and refining the internal structure of cement paste which reduce the flow capabilities of cement paste containing nanokaolin and metakaolin.

Chaotic dynamics of large-amplitude alfvén-wave trains in the solar wind.

2001 ◽  
Vol 28 (5) ◽  
pp. 771-774 ◽  
Author(s):  
F.A. Borotto ◽  
A.C.-L. Chian ◽  
A.L.C. Gonzalez ◽  
W.D. Gonzalez ◽  
B.T. Tsurutani
Keyword(s):  
Solar Wind ◽  
Large Amplitude ◽  
Chaotic Dynamics ◽  
Alfven Wave ◽  
Wave Trains

scholarly journals Alfvén waves in the magnetosphere generated by shock wave / plasmapause interaction

2019 ◽  
Vol 5 (2) ◽  
pp. 9-14
Author(s):  
Анатолий Леонович ◽  
Anatoliy Leonovich ◽  
Цюган Цзун ◽  
Qiugang Zong ◽  
Даниил Козлов ◽  
...  
Keyword(s):  
Shock Wave ◽  
Alternative Hypothesis ◽  
Contact Region ◽  
High Energy ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
High Energy Particle ◽  
Secondary Source ◽  
Wave Passage

We study Alfvén waves generated in the magnetosphere during the passage of an interplanetary shock wave. After shock wave passage, the oscillations with typical Alfvén wave dispersion have been detected in spacecraft observations inside the magnetosphere. The most frequently observed oscillations are those with toroidal polarization; their spatial structure is described well by the field line resonance (FLR) theory. The oscillations with poloidal polarization are observed after shock wave passage as well. They cannot be generated by FLR and cannot result from instability of high-energy particle fluxes because no such fluxes were detected at that time. We discuss an alternative hypothesis suggesting that resonant Alfvén waves are excited by a secondary source: a highly localized pulse of fast magnetosonic waves, which is generated in the shock wave/plasmapause contact region. The spectrum of such a source contains oscillation harmonics capable of exciting both the toroidal and poloidal resonant Alfvén waves.

scholarly journals e±-rich GRB Fireball and Infrared Flashes

2003 ◽  
Vol 214 ◽  
pp. 331-332
Author(s):  
Zhuo Li ◽  
Z. G. Dai ◽  
T. Lu
Keyword(s):  
Gamma Ray ◽  
Lorentz Factor ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Rapid Response ◽  
Model Parameters ◽  
Wide Range ◽  
Very High Energy ◽  
Very High

Gamma-ray bursts (GRBs) are believed to originate from ultra-relativistic fireballs, with initial Lorentz factor η ∼ 102 − 103. However very high energy photons may still suffer from γγ interaction. We show here that in a wide range of model parameters, the resulting pairs may dominate electrons associated with the fireball baryons. This may provide an explanation for the rarity of prompt optical detections. A rapid response to the GRB trigger at the IR band would detect such a strong flash.

scholarly journals HIGH ENERGY EMISSION OF GRB 130821A: CONSTRAINING THE DENSITY PROFILE OF THE CIRCUM-BURST MEDIUM AS WELL AS THE INITIAL LORENTZ FACTOR OF THE OUTFLOW

2014 ◽  
Vol 781 (2) ◽  
pp. 74 ◽  
Author(s):  
Yun-Feng Liang ◽  
Bei Zhou ◽  
Hao-Ning He ◽  
Pak-Hin Thomas Tam ◽  
Yi-Zhong Fan ◽  
...  
Keyword(s):  
Density Profile ◽  
Lorentz Factor ◽  
High Energy ◽  
Energy Emission ◽  
High Energy Emission

Phenothiazine protection in calcium overload-induced heart failure: a possible role for calmodulin

1983 ◽  
Vol 244 (3) ◽  
pp. H328-H334
Author(s):  
S. W. Schaffer ◽  
K. P. Burton ◽  
H. P. Jones ◽  
H. H. Oei
Keyword(s):  
Heart Failure ◽  
Creatine Phosphokinase ◽  
Potent Inhibitor ◽  
High Energy ◽  
Major Effect ◽  
Calcium Overload ◽  
Cellular Damage ◽  
Maximal Response ◽  
Membrane Changes ◽  
Calcium Permeability

The effect of several phenothiazines on the extent of cellular damage resulting from the calcium paradox was examined. Hearts treated with trifluoperazine, a potent calmodulin inhibitor, exhibited less cellular damage than untreated myocardium as reflected by light microscopy, high-energy phosphate content and the loss of protein and creatine phosphokinase into the perfusate. A dose response of this effect revealed a maximal response at about 1 microM trifluoperazine, a concentration which lies well within the range generally attributed to calmodulin inhibition. Several other lines of evidence were also obtained suggesting a possible role for calmodulin in calcium-overload induced necrosis. First, the phenothiazines had little influence on membrane changes believed responsible for altered calcium permeability. Second, trifluoperazine was without major effect unless included in the reperfusion buffer, indicating that the drug is only effective during the phase associated with calcium overload. Finally, less protection was afforded hearts exposed to phenothiazines such as chlorpromazine and promethazine, which are weaker inhibitors of calmodulin, than those treated with the potent inhibitor trifluoperazine. While other interpretations are possible, these studies are consistent with a role for calmodulin in calcium overload-induced heart failure.

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