This work explores the effects of quantum matter on classical spacetime through the theory of semiclassical gravity. Renormalization in curved spaces using Hadamard states is employed to calculate the energy momentum tensor. Solutions in ultrastatic and globally hyperbolic spacetimes are presented, highlighting the complexity of fourth-order semiclassical equations and the conditions...
The Relativistic jets are main sources of radio emission in the Universe. Multiscale flows in jets require of using to adaptive mesh technique. In talk will propose original the Patch-Block-Structured Adaptive-Mesh-Refinement technique for multi-scale modeling of relativistic jets. To use this technique, the numerical method was redesigned in a special way by means Coarray Fortran technology....
The Universe is currently in a phase of accelerated expansion, a fact that was experimentally proven in the late 1990s. Cosmological models involving scalar fields allow the description of this accelerated expansion regime in the Cosmos and present themselves as a promising alternative in the study of the inflationary eras, especially the actual one which is driven by the dark energy. In this...
The recent NICER observational data for the pulsars PSR J0030+0451 [[1]][1] and PSR J$0740+6620$ [[2]][2] impose new constrains in the mass-radius diagram of the corresponding compact star. Here, we investigate the possibility of such astrophysical object being a quark star. In particular, the quark matter is described by a holographic model with $N_c$ D3 branes and $N_f$ D7 probe branes,...
The evolution of the scalar fluctuations via the Wigner formalism shows that the Wigner function is "squeezed". This result leads us to interpret the inflationary dynamics within the framework of open quantum systems, using the Lindblad master equation to model the interaction of quantum perturbations with their environment. This approach provides a deep understanding of the transition from...
Modify gravity theories have received huge attention in the last decade. In this work, we find the Wheeler-DeWitt (WDW) equation in the Quantum Cosmology (QC) scenario for a Friedmann-Lemaitre-Robertson-Walker (FLRW) model using the deformed phase space in f(R) gravity.
In this study, we investigate Weakly Interacting Massive Particles as candidates for dark matter within an extended Standard Model framework that incorporates both scalar and fermion fields. We calculate the relic density and spin-independent scattering cross-section for these dark matter candidates and compare our results with the values reported by the PLANCK and XENON collaborations. Our...
G166.0+4.3 (VRO 42.05.01) is a mixed-morphology supernova remnant having a different spatial distribution of emission viewed in radio and X-rays. A sharp edge-brightened circular shape of the shell and wing component is visible in radio wavelength. Whereas X-ray emission is dominated by a bright spot in the wing, without any edge-brightened structures. Observed shape of this SNR looking like a...
Studying the galactic chemical evolution with short lived radioisotopes (SLRs) has a significant advantage over using stable elements: Due to their radioactive decay, SLRs carry additional timing information on astrophysical nucleosynthesis sites.
We can use meteoritic abundance data in conjunction with a chemical evolution model to constrain the physical conditions in the last rapid...
Damour-Solodukhin wormholes are intriguing theoretical constructs that closely mimic many properties of black holes. This study examines two specific aspects of the waveforms emitted from these wormholes: the late-time tails and echoes, which are pivotal in distinguishing them from black holes. Both features manifest in the later stages of quasinormal oscillations and originate from...
A diverse array of equations of state (EoSs), formulated within the covariant density functional theory of hadronic matter and incorporating density-dependent couplings, is leveraged to scrutinize polar f- and p-oscillations in both cold and hot compact stars. We delve into the correlations between oscillation frequencies of cold purely nucleonic neutron stars (NSs), their global parameters,...
Machu Piqchu has been variously described as a citadel, a lost city, a royal estate, and a sacred center. Machu Piqchu was likely recognized by the Inkas as a place of power because of its many granite outcrops and caves and the cardinality of mountains such as Veronica, Machu Piqchu, Wayna Piqchu, Pumasillo, and the snow peak of Salcantay. Machu Piqchu is a multi-faceted complex that exhibits...
The Inkas worshipped the Sun, and their emperor was thought to be the son of the Sun. They conquered most of the Andes and their former empire is replete with examples of their astronomy. They used solar positions on the horizon for calendrical purposes and managed their crops and religious festivals in this manner. Many examples remain of their intentional light and shadow effects that...
Este estudo investiga perturbações e aspectos-chave de um modelo de buraco negro com correções quânticas dentro do framework da Gravidade Quântica em Loop. Calculamos os modos quasi-normais, revelando uma dependência significativa dos parâmetros da Gravidade Quântica em Loop. Ao mesmo tempo, avaliamos a estabilidade do buraco negro quântico. Nossos resultados sugerem possibilidades...
Mkn 180 is the BL Lac object with spectrum has been measured through radio and X-ray band to high energy gamma-rays. This object is considered as a potential candidate for the source of high-energy leptonic and\or hadronic cosmic-ray acceleration. Also, it has been proposed to be a GeV – TeV gamma-ray source. The very high energy gamma-rays from Mkn 180 were detected due to the trigger...
Active galactic nucleus (AGN) phenomenon and a role of jets, powered by central black hole of AGN, in the feedback of the surroundings on the different scales is the matter of the detailed multiwavelength investigations. The long-term observations of AGNi are used to reveal the processes taking place in the very proximity to the supermassive black holes. One of the approaches to such studies...
we develop and apply the WKB-type approximation to several examples
of noncommutative quantum cosmology, obtaining the time evolution of the noncommutative universe. This is accomplished by starting from a noncommutative quantum formulation of cosmology, where the noncommutativity is introduced by a deformation on the minisuperspace variables. This procedure gives a straightforward algorithm...
For a deeper understanding of the physical processes at play in solar
flares, it is necessary to analyse the flare emissions at multiple wavelengths. This multi-frequency approach enables the characterisation of energetic electrons accelerated from tens of keV and up to several hundreds of MeV. This study reports on the observation of nine solar flares, in which the spectral parameters were...
I will describe recent work showing how to estimate the abundance of black holes which formed over an extended period of time, with a wide spectrum of masses, during radiation domination.
In this work, we propose a generalization of the improved gauge unfixing formalism in order to generate gauge symmetries in the non-Abelian valued systems. This generalization displays a proper and formal reformulation of second-class systems within the phase space itself. Then, we present our formalism in a manifestly gauge invariant resolution of the $SU(N)$ massive Yang-Mills and $SU(2)$...
We review a General Relativistic (GR) method to determine the black hole (BH) parameters: mass-to-distance ratio, position and recessional velocity of 16 active galactic nuclei (AGNs) of Seyfert type, which have an accretion disk with water masers circulating around the BH. This GR method makes use of astrophysical observations: the redshifted and the blueshifted photons emitted from the...
In this work, space-time will be studied taking into account a geometric structure of affine space, which can be identified with $\mathbb{R}^4$ space. The focus will be on the development of non-inertial reference systems, also called observers, and the description of the effects that can be physically measured by them. Therefore, in addition to discussing concepts such as world line, the...
As seen in most textbooks of astrophysics, most astronomical bodies such as main sequence stars have been investigated only by Newtonian gravity. This is presumably based on a belief that Newtonian physics could be sufficient to extract important physics of most astronomical bodies except compact stars, and that General Relativity would be too precise to be suitable.
In this talk, I will...
Experimentally, the creation of Quark Gluon Plasma in relativistic heavy ion collisions is well known; its properties are being investigated in different experiments around the world at different energies. However, the results from proton-proton collisions are under debate since there are results with behavior like those observed in heavy ion collisions, for instance, collective phenomena,...
Recently, the FPF LHC neutrino detector recorded its first measurements, opening new possibilities for studying weak interactions. In this work, we explore related observable, such as the proton structure function ($F_2$) from weak interactions, and the cross section of $W^+W^- \rightarrow X$ and $\gamma W^- \rightarrow X$, which could be significant for future colliders. We employ QCD...
We study the hypothesis of deformation of the Lorentz transformations by a universal minimum velocity and we seek to apply this hypothesis to superfluids. Relating the minimum velocity to the idea of a fluid, with superfluid properties, in previous works we related the minimum velocity to the cosmological constant and even to cosmic inflation. Soon we could generate a hypothetical superfluid...
The Lagrangian of matter is a crucial component in the action of relativistic gravity theories with matter couplings, such as general relativity. Particularly in alternative gravity theories featuring non-minimal curvature-matter couplings, the matter Lagrangian explicitly figures in the field equations. Consequently, its precise value is necessary to fully compute these field equations. In...
4U2129+47 is classified as a Low-Mass X-ray Binary containing a neutron star. It is actively studied in the optical and X-ray. It was found that exhibit both outburst and quiescent states. The spectroscopic investigations of optical counterpart of neutron star in this binary system shown that the 4U 2129+47 is a hierarchical triple system. X-ray observations shown the evidence for a spatially...
The existence of the HI regions in dark matter halos of a number of galaxies is the observational fact. Each of the eight galaxies analyzed by observers had approximately the same maximum surface brightness temperature throughout its disc, what was explained by the self-absorption in the hydrogen line 21 cm. The opacity or absorption coefficient τν is controlled by the column density NH of...
