Search results for "AFTERGLOW"
showing 10 items of 62 documents
Numerical simulations of dynamics and emission from relativistic astrophysical jets
2013
Broadband emission from relativistic outflows (jets) of active galactic nuclei (AGN) and gamma-ray bursts (GRBs) contains valuable information about the nature of the jet itself, and about the central engine which launches it. Using special relativistic hydrodynamics and magnetohydronamics simulations we study the dynamics of the jet and its interaction with the surrounding medium. The observational signature of the simulated jets is computed using a radiative transfer code developed specifically for the purpose of computing multi-wavelength, time-dependent, non-thermal emission from astrophysical plasmas. We present results of a series of long-term projects devoted to understanding the dyn…
Numerical models of blackbody-dominated gamma-ray bursts – I. Hydrodynamics and the origin of the thermal emission
2014
GRB 101225A is a prototype of the class of blackbody-dominated (BBD) gamma-ray bursts (GRBs). It has been suggested that BBD-GRBs result from the merger of a binary system formed by a neutron star and the helium core of an evolved star. We have modelled the propagation of ultrarelativistic jets through the environment left behind the merger by means of relativistic hydrodynamic simulations. In this paper, the output of our numerical models is post-processed to obtain the (thermal) radiative signature of the resulting outflow. We outline the most relevant dynamical details of the jet propagation and connect them to the generation of thermal radiation in GRB events akin to that of GRB 101225A…
Tunneling luminescence in long lasting afterglow of SrAl 2 O 4 :Eu,Dy
2017
The publication is prepared with the financial support of National Research Programme IMIS2.
Deceleration of arbitrarily magnetized GRB ejecta: the complete evolution
2008
(Abridged) We aim to quantitatively understand the dynamical effect and observational signatures of magnetization of the GRB ejecta on the onset of the afterglow. We perform ultrahigh-resolution one-dimensional relativistic MHD simulations of the interaction of a radially expanding, magnetized ejecta with the interstellar medium. The need of ultrahigh numerical resolution derives from the extreme jump conditions in the region of interaction between the ejecta and the circumburst medium. We study the evolution of an ultrarelativistic shell all the way to a the self-similar asymptotic phase. Our simulations show that the complete evolution can be characterized in terms of two parameters, name…
Afterglow, TL and OSL properties of Mn2+-doped ZnGa2O4 phosphor
2019
The work was supported by Latvian Research Council via LZP-2018/1–0214 research project as well as the Latvian-Ukrainian Joint Research Project (LV-UA/2016/1 in Latvia and M/8-2018 (No. 0118U001672) in Ukraine), and by the NATO SfP Project G4649. The work was also partially supported by the Polish National Science Center (project 2018/31/B/ST8/00774). A. Luchechko gratefully acknowledges a grant from Institute of Physics PAS for a research visit to the Institute.
Hackmanite—The Natural Glow-in-the-Dark Material
2020
“Glow-in-the-dark” materials are known to practically everyone who has ever traveled by airplane or cruise ship, since they are commonly used for self-lit emergency exit signs. The green afterglow, persistent luminescence (PeL), is obtained from divalent europium doped to a synthetic strontium aluminate, but there are also some natural minerals capable of afterglow. One such mineral is hackmanite, the afterglow of which has never been thoroughly investigated, even if its synthetic versions can compete with some of the best commercially available synthetic PeL materials. Here we combine experimental and computational data to show that the white PeL of natural hackmanite is generated and cont…
The boron effect on low temperature luminescence of SrAl2O4:Eu, Dy
2020
V.V. acknowledges the financial support of ERDF PostDoc project No. 1.1.1.2/VIAA/3/19/440 (University of Latvia Institute of Solid State Physics, Latvia) and K.S., I.B., A.Z., D.M. and K.L. acknowledge the financial support of ERDF, European-Union Project No. 1.1.1.1/16/A/182 (University of Latvia Institute of Solid State Physics, Latvia).
Low temperature afterglow from SrAl 2 O 4 : Eu, Dy, B containing glass
2020
V.V. acknowledges the financial support of ERDF PostDoc project No. 1.1.1.2/VIAA/3/19/440 (University of Latvia Institute of Solid State Physics, Latvia) and LP the Academy of Finland (Flagship Programme, Photonics Research and Innovation PREIN 320165 and Academy Project -326418) for the financial support. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01- 2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART 2 .
The search for defects in undoped SrAl2O4 material
2019
This research project was supported financially by ERDF Project No: Nr.1.1.1.1/16/A/182 .
UV and X-ray excited red persistent luminescence in Mn2+ doped MgGeO3 material synthesized in air and reducing atmosphere
2021
Abstract Materials with long persistent luminescence (PersL) have caused widespread interest among scientists and industry for decades. Currently, there is widely available information on the long persistent luminescence materials with emission in the blue and green spectral range, while the number of publications on the afterglow in the red and near-infrared spectral range is considerably lower. In the course of this work MgGeO3 material doped with 0.1 mol% Mn2+ was produced using solid-state reaction synthesis in ambient and reducing atmospheres. The material exhibits a broad luminescence band with a peak around 680 nm, excited by either X-rays or UV. After cessation of irradiation, the a…