1,868 research outputs found
Emergent GUP from Modified Hawking Radiation in Einstein-NED Theory
We present a general procedure for constructing exact black hole (BH)
solutions with the magnetic charge in the context of nonlinear electrodynamics
(NED) theory as well as in the coherent state approach to noncommutative
geometry (NCG). In this framework, the Lagrangian density for the
noncommutative Hayward BH is obtained and the weak energy condition (WEC) is
satisfied. The noncommutative Hayward solution depends on two kind of charges
which for the vanishing of them yields the Schwarzschild solution. Moreover, in
order to find a link between the BH evaporation and uncertainty relations, we
may calculate the Hawking temperature and find the effect of the Lagrangian
density of BHs on the Hawking radiation. Therefore, a generalized uncertainty
principle (GUP) emerges from the modified Hawking temperature in Einstein-NED
theory. The origin of this GUP is the combined influence of a nonlinear
magnetic source and an intrinsic property of the manifold associated with a
fictitious charge. Finally, we find that there is an upper bound on the
Lagrangian uncertainty of the BHs which are sourced by the NED field and/or the
fictitious charge.Comment: 24 pages, 3 figures, 1 table, new issues in Introduction and new
References are added, Title is changed, minor revisions in Abstract and
Conclusion
Relation between winds and jets in radio-loud AGN
We investigate the relation between the two modes of outflow (wind and jet)
in radio-loud active galactic nuclei (AGN). For this study we have carried out
a systematic and homogeneous analysis of XMM-Newton spectra of a sample of 16
suitable radio-loud Seyfert-1 AGN. The ionised winds in these AGN are
parameterised through high-resolution X-ray spectroscopy and photoionisation
modelling. We discover a significant inverse correlation between the column
density NH of the ionised wind and the radio-loudness parameter R of the jet.
We explore different possible explanations for this NH-R relation and find that
ionisation, inclination, and luminosity effects are unlikely to be responsible
for the observed relation. We argue that the NH-R relation is rather a
manifestation of the magnetic driving mechanism of the wind from the accretion
disk. Change in the magnetic field configuration from toroidal to poloidal,
powering either the wind or the jet mode of the outflow, is the most feasible
explanation for the observed decline in the wind NH as the radio jet becomes
stronger. Our findings provide evidence for a wind-jet bimodality in radio-loud
AGN and shine new light on the link between these two modes of outflow. This
has far-reaching consequences for the accretion disk structure and the wind
ejection mechanism.Comment: Accepted for publication in Astronomy & Astrophysics (A&A), 10 pages,
4 figure
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