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Cover Picture: Astron. Nachr. 1/2024 Astron. Nachr. (IF 0.9) Pub Date : 2024-03-14 L. R. Bedin, J. Dietrich, A. J. Burgasser, D. Apai, M. Libralato, M. Griggio, C. Fontanive, D. Pourbaix
Motion on the sky of the brown dwarf binary system Luhman 16 AB. At a distance of less than 2 pc, it is known as the nearest pair of this type to Earth. (Top:) The entire 4.7ʹ × 4ʹ region surrounding Luhman 16 AB, as monitored by HST. (Bottom:) Zoom‐in of the 25ʺ × 7ʺ rectangular region indicated in red in the top panel, showing the complete trajectory in the sky of Luhman 16 A and B during the period
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HST astrometry of the closest brown dwarfs-II. Improved parameters and constraints on a third body Astron. Nachr. (IF 0.9) Pub Date : 2024-03-08 L. R. Bedin, J. Dietrich, A. J. Burgasser, D. Apai, M. Libralato, M. Griggio, C. Fontanive, D. Pourbaix
Located at less than two pc away, Luhman 16 AB (WISE J104915.57-531906.1) is the closest pair of brown dwarfs and the third closest “stellar” system to Earth. An exoplanet candidate in the Luhman 16 binary system was reported in 2017 based on a weak astrometric signature in the analysis of 12 HST epochs. An additional epoch collected in 2018 and re-analysis of the data with more advanced methods further
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Spectroscopic and photometric behavior of LP Ori Astron. Nachr. (IF 0.9) Pub Date : 2024-02-29 Aslı Elmaslı, Kübra Özge Ünal, Doğus Özuyar
We performed spectroscopic and photometric analyses on the early B-type LP Ori young stellar object located in the Orion Nebula. The high-resolution spectra of LP Ori was obtained at the Ankara University Kreiken Observatory in 2023, while all spectra recorded over the past 19 years were extracted from the ESO and ESPaDOnS archives. In these spectra of LP Ori, there is typically an emission observed
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On the chemical composition of the evolved very bright metal-poor star HD 1936 Astron. Nachr. (IF 0.9) Pub Date : 2024-02-28 Şeyma Çalışkan, Jannat Mushreq Kamil Alazzawi, Yahya Nasolo
We present chemical abundances of the very bright metal-poor star HD 1936 based on high-resolution and high SNR spectra from AUKR. We obtain the abundances of 29 atomic species with atomic numbers between 3 and 63. In this context, the derived lithium abundance of 1.01 is consistent with the thin Li plateau observed in lower red giant branch stars. The star is a carbon-normal with a ratio of −0.31
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Calculated brightness temperatures of solar structures compared with ALMA and Metsähovi measurements Astron. Nachr. (IF 0.9) Pub Date : 2024-02-28 Filip Matković, Roman Brajša, Matej Kuhar, Arnold O. Benz, Hans -G. Ludwig, Caius L. Selhorst, Ivica Skokić, Davor Sudar, Arnold Hanslmeier
The Atacama Large Millimeter/submillimeter Array (ALMA) allows for solar observations in the wavelength range of 0.3–10 mm, giving us a new view of the chromosphere. The measured brightness temperature at various frequencies can be fitted with theoretical models of density and temperature versus height. We use the available ALMA and Metsähovi measurements of selected solar structures (quiet sun (QS)
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Lessons from the apparent peculiar nature of the star TYC 6544‐3483‐1 Astron. Nachr. (IF 0.9) Pub Date : 2024-02-27 Josep Martí, Pedro L. Luque‐Escamilla, Benito Marcote, Daniel del Ser, Gustavo E. Romero, Cintia S. Peri
We report a radio and optical study of the star TYC 6544‐3483‐1 originally selected as a follow‐up target in the course of our efforts to cross‐identify Galactic high‐energy sources. The star by itself finally turned out to be a very ordinary main‐sequence star despite the initial expectations that apparently pointed to the contrary. We found that its, at first glance, exotic properties arise as a
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SNe 2019vxm and 2020tlf: two luminous type II Supernovae with signatures of circumstellar interaction Astron. Nachr. (IF 0.9) Pub Date : 2024-02-24 Dmitry Yu Tsvetkov, Nickolay N. Pavlyuk, Alexandr V. Dodin, Nickolay I. Shatsky, Sergey A. Potanin, Nataliya P. Ikonnikova, Marina A. Burlak, Aleksandr A. Belinskii, Igor M. Volkov, Vsevolod A. Echeistov
We present optical spectroscopic and photometric observations of type II SNe 2019vxm and 2020tlf. The photometric monitoring of SN 2019vxm continued for 592 days, two spectra were collected. SN 2020tlf was observed for 163 days and we obtained one spectra. The maximum luminosity of both SNe is high: mag for SN 2019vxm and SN 2020tlf, respectively. SN 2019vxm displays typical for most of SNe IIn photometric
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Spin period evolution of Vela pulsar based on the wind emission: Application to the long period radio pulsars GPM J1839-10 (P = 21 min) and GLEAM-X J1627 (P = 18 min) Astron. Nachr. (IF 0.9) Pub Date : 2024-02-20 Yi-Hong Sun, De-Hua Wang, Cheng-Min Zhang, Xiang-Han Cui, Jian-Wei Zhang, Jing Yu, Yun-Gang Zhou, Zi-Yi You
The Vela pulsar is a young neutron star with spin period of P = 89 ms and a measured low braking index (˜1.4) that is much less than the standard value of 3 predicted by the magnetic dipole radiation (MDR) model; however, its spin period evolution has been a mystery. In this article, we assume that the spin-down of the Vela pulsar is attributed to both MDR and wind flow (hereafter MDRW), and find that
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Dirac spinor scattering states with positive-energy in rotating spheroid models Astron. Nachr. (IF 0.9) Pub Date : 2024-02-17 Zhi-Fu Gao, Ci-Xing Chen, Na Wang, Xin-Jun Zhao, Zhao-Jun Wang
There are many rotating spheroids in the universe, and many astronomers and physicists have used theoretical methods to study the characteristics of stellar gravity since Newton's time. This paper derives the solutions of eight scattering states (ϕ(0),χ(0),ϕ(1),χ(1),ϕ(2)$$ \Big({\phi}^{(0)},{\chi}^{(0)},{\phi}^{(1)},{\chi}^{(1)},{\phi}^{(2)} $$,χ(2),ϕ(3)$$ {\chi}^{(2)},{\phi}^{(3)} $$, andχ(3))$$ {\chi}^{(3)}\Big)
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Simple calculation of the Moon apsides motion Astron. Nachr. (IF 0.9) Pub Date : 2024-02-20 V. V. Nesterenko
A simple and clear method to calculate the averaged motion of the apsis line in the Moon orbit is proposed. The obtained result is for the starry period of the Moon revolution around the Earth or per year. The modern observed value of the latter quantity is per year. In “Principia” Newton derived for the Moon month and per year, that is approximately two times less than the observed values. Contrary
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Orbit of the visual binary star 61 Cyg Astron. Nachr. (IF 0.9) Pub Date : 2024-02-13 I. S. Izmailov, A. A. Apetyan
We present the orbit and the mass estimates for the components of the visual binary star 61 Cyg obtained with the positional observations, including the high-precision Gaia data, and the measurements of differences in the radial velocities and the radial accelerations of the components. Since the orbital period of this star significantly exceeds the period of observations, using the radial velocities
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Effects of a generalized uncertainty principle on the MIT bag model equation of state Astron. Nachr. (IF 0.9) Pub Date : 2024-02-08 Marcelo Netz-Marzola, César A. Zen Vasconcellos, Dimiter Hadjimichef
The Generalized Uncertainty Principle (GUP) is motivated by the premise that spacetime fluctuations near the Planck scale impose a lower bound on the achievable resolution of distances, leading to a minimum length. Inspired by a semiclassical method that integrates the GUP into the partition function by deforming its phase space, we induce a modification on the thermodynamic quantities of the MIT bag
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An alternative, versatile, high-tolerance design of a modified Richter–Slevogt camera, using standard glasses Astron. Nachr. (IF 0.9) Pub Date : 2024-02-06 Nishant Neeraj Gadey
Prime-focus catadioptric astrographs have been used for a long time in various astronomical applications. The prime advantage offered by them is the capability to produce remarkably wide fields of view, and hence generate a huge amount of data in relatively less observation time. An emerging application of such wide-field astrographs is in the form of telescope arrays. While this has been implemented
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On the chemical abundance differences between the solar twin visual binary system 16 Cygni A and B Astron. Nachr. (IF 0.9) Pub Date : 2024-02-06 Yoichi Takeda
The visual binary system 16 Cyg A+B consists of similar solar twins, but a planetary companion is detected only in B. An intensive spectroscopic differential analysis is carried out to the Sun, 16 Cyg A, and 16 Cyg B, with particular attention being paid to (i) precisely establishing the differential atmospheric parameters/metallicity between A and B, and (ii) determining the important CNO abundances
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Particle acceleration test with Cas A multiwavelength emission Astron. Nachr. (IF 0.9) Pub Date : 2024-02-01 Vera G. Sinitsyna, Vera Y. Sinitsyna
The investigation of supernova remnants (SNRs) across the electromagnetic spectrum from radio up to very high energy gamma-rays can serve as a test of the particle acceleration and touches on one of the unresolved problems of modern astrophysics, namely the origin of cosmic rays and the Galaxy's contribution to the overall cosmic ray spectrum. The multiwavelength observations of Cas A SNR demonstrated
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Astrophysical approach to search for heavy neutrino decay Astron. Nachr. (IF 0.9) Pub Date : 2024-02-01 Vera G. Sinitsyna, Vera Y. Sinitsyna
Cosmic rays are a very valuable tool of multi-messenger astrophysics, as they provide a very different picture of the sky. During the past decades, a large number of active astrophysical objects in our Galaxy and beyond have been discovered through the detection of gamma-rays with Cherenkov telescopes. Cosmic rays, neutrinos have been successfully supplementing the astronomical view. Also, cosmic rays
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Mini-outburst of black hole X-ray binary GX 339-4 in 2004 Astron. Nachr. (IF 0.9) Pub Date : 2024-02-01 Xue-Kun Zhang, Wei-Long He, Wei-Jia Yang, Ai-Jun Dong
The mini-outburst of black hole X-ray binaries (BHXBs) is a re-bright event of light curve, which is often detected in BHXBs with the low orbital period, such as XTE J1650-500 ( P orb ≈ 7.69 ± 0.02 hr $$ {P}_{\mathrm{orb}}\approx 7.69\pm 0.02\kern0.22em \mathrm{hr} $$ ), GRO J0422+32 ( P orb ≈ 5.091850 ± 0.000005 hr $$ {P}_{\mathrm{orb}}\approx 5.091850\pm 0.000005\kern0.22em \mathrm{hr} $$ ) and Swift
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Measurements of visual double stars with PISCO2 at the Nice 76-cm refractor in 2016–2017 Astron. Nachr. (IF 0.9) Pub Date : 2024-01-30 Jean-Louis Prieur, René Gili, Jean-Pierre Rivet, Farrokh Vakili, Marco Scardia, Luigi Pansecchi, Robert W. Argyle, Josefina F. Ling, Luca Piccotti, Eric Aristidi, Laurent Koechlin, Daniel Bonneau, Luca Maccarini, Jocelyn Serot
We present relative astrometric and photometric measurements of visual double stars made in 2016–2017, with PISCO2 installed at the 76-cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. Three different techniques were used for obtaining measurements: Lucky Imaging, Speckle Interferometry and
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On CCGG, the De Donder-Weyl Hamiltonian formulation of canonical gauge gravity Astron. Nachr. (IF 0.9) Pub Date : 2024-01-25 David Vasak, Johannes Kirsch, Armin van de Venn, Vladimir Denk, Jürgen Struckmeier
This short paper gives a brief overview of the manifestly covariant canonical gauge gravity (CCGG) that is rooted in the De Donder-Weyl Hamiltonian formulation of relativistic field theories, and the proven methodology of the canonical transformation theory. That framework derives, from a few basic physical and mathematical assumptions, equations describing generic matter and gravity dynamics with
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The magnetar crustal magneto-thermal evolution Astron. Nachr. (IF 0.9) Pub Date : 2024-01-25 Hui Wang, Zhi Bing Li, Xiao Feng Yang, Dong Ling Song
Magnetars are a type of pulsars powered by magnetic field energy. Part of the X-ray luminosities of magnetars in quiescence have a thermal origin and can be fitted by a blackbody spectrum with the surface temperature, much higher than the typical values for rotation-powered pulsars. The persistent thermal emissions and bursts of magnetars indicate the presence of some internal heat sources in their
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Singularity attenuation with quantum-mechanically revisited metric tensor Astron. Nachr. (IF 0.9) Pub Date : 2024-01-24 Abdel Nasser Tawfik, Tahia F. Dabash, Azzah Elshehri
The space and initial singularities are reexamined in the most reliable solutions to the Einstein's field equations (EFE), that is, the Einstein–Gilbert–Straus (EGS) metric. In discretized Finsler geometry, additional curvatures and thereby geometric structures likely emerge, which are distinct from the conventional spacetime curvatures and geometric structures that the Einstein's theory of general
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Non-symmetrical sparking may hint “zits” on a pulsar surface Astron. Nachr. (IF 0.9) Pub Date : 2024-01-24 Zhengli Wang, Jiguang Lu, Jingchen Jiang, Shunshun Cao, Weiyang Wang, Enwei Liang, Renxin Xu
Pulsar electrodynamics could be relevant to the physics of stellar surface, which remains poorly understood for more than half a centenary and is difficult to probe due to the absence of direct and clear observational evidence. Nevertheless, highly sensitive telescopes (e.g., China's Five-hundred-meter Aperture Spherical radio Telescope, FAST) may play an essential role to solve the problem since the
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Constraints on Bose–Einstein condensate stars as neutron stars models from new observational data Astron. Nachr. (IF 0.9) Pub Date : 2024-01-22 Adriel E. Rodríguez Concepción, Gretel Quintero Angulo
We evaluate the feasibility of Bose–Einstein condensate stars (BECS) as models for the interior of neutron stars (NSs). BECS are compact objects composed of bosons, formed through the spin-parallel pairing of neutrons. Here, we utilize the astronomical data from GW170817, XMMU J173203.3-344518 (the lightest NS known), and a novel lower limit on NS core heat capacity to scrutinize the compatibility
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Bright spectroscopic binaries: III. Binary systems with orbital periods of P > 500 days Astron. Nachr. (IF 0.9) Pub Date : 2024-01-22 Dennis Jack, Missael Alejandro Hernández Huerta, Faiber Danilo Rosas-Portilla, Klaus-Peter Schröder
We present an analysis of nine bright spectroscopic binaries (HD 1585, HD 6613, HD 12390, HD 39923, HD 55201, HD 147430, HD 195543, HD 202699, HD 221643), which have orbital periods of P>500$$ P>500 $$ days. These well-separated binaries are the last stars of our sample that we observed with the TIGRE telescope obtaining intermediate-resolution spectra of R≈20,000$$ R\approx \mathrm{20,000} $$. We
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Limitations of the modified blackbody fit method for determining molecular cloud properties Astron. Nachr. (IF 0.9) Pub Date : 2024-01-20 Niko Zielinski, Sebastian Wolf
Achieving a comprehensive understanding of the star and planet formation process is one of the fundamental tasks of astrophysics, requiring detailed knowledge of the physical conditions during the different phases of this process. During the earliest stages, that is, concerning physical processes in molecular clouds and filaments, the column density N(H2), dust temperature T $$ T $$ and dust emissivity
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Extended linear-sigma model: transport properties of QCD matter at finite temperature Astron. Nachr. (IF 0.9) Pub Date : 2024-01-18 Adel Nasser Tawfik, Azzah Elshehri
Since their discovery in heavy-ion collisions, the transport properties of quantum chromodynamics (QCD) matter gained prominence among nuclear theorists. We introduce a new study based on a QCD-like effective model. The thermal evolution of the electric and heat conductivity, σe$$ {\sigma}_e $$ and κ$$ \kappa $$, respectively, and that if their ratios are evaluated in SU(3) extended linear-sigma model
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A comparative study on the spectra of normal outburst and mini-outbursts of black hole X-ray binary XTE J1550-564 Astron. Nachr. (IF 0.9) Pub Date : 2024-01-18 Wei-Long He, Xue-Kun Zhang, Wei-Jia Yang, Ai-Jun Dong, Kang Ge
One normal outburst and three mini-outbursts have been detected by Rossi X-ray Timing Explorer (RXTE) satellite after 2000 in the well-known black hole X-ray binary XTE J1550-564. In our work, we explored the energy spectral properties of the four outbursts and the three mini-outbursts retained in the Low/Hard state. The results show that the X-ray spectra of the three mini-outbursts are harder than
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Experimental astronomical observation using a lobster eye optics Astron. Nachr. (IF 0.9) Pub Date : 2024-01-17 Veronika Stieglitz, Dirk Stieglitz, René Hudec, Martin Jelinek
A lobster eye (LE) is a wide-field type of X-ray optics, which provides a large field of view at the expense of angular resolution. The optics presented in this paper are the LE optics in Schmidt arrangement made from glass sheets with golden reflective coatings. It was used as a scientific payload on the WRXR rocket experiment. Before the mission itself, the optics was tested on ground to obtain more
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Improving the descendant relationship of cluster galaxies at z < 1 Astron. Nachr. (IF 0.9) Pub Date : 2024-01-16 Cleivison Souza de Jesus, Andre Luis Batista Ribeiro, Christine Cordula Dantas
In this work, we study how to improve well-known techniques for detecting progenitors/descendants of galaxies, such as the NDpredict program, when applied to galaxies in clusters. The improvement of this particular method is based on the use of the red sequence of galaxies in those environments. Objects close to the red sequence in the color and magnitude diagram are more likely to belong to the cluster
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Charmed meson pair production in high-energy pp collisions within the QCD color dipole approach Astron. Nachr. (IF 0.9) Pub Date : 2024-01-11 Glauber Sampaio dos Santos, Gustavo Gil da Silveira, Magno Valério Trindade Machado
A study of double-charmed meson production in high-energy proton–proton collisions at the Large Hadron Collider is presented. Considering the color dipole formalism developed in the transverse momentum representation along with the double parton scattering mechanism, predictions are made for the transverse momentum differential cross section for different pairs of D$$ D $$-mesons. The theoretical results
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Evolution of hard gluons in a medium with q^(t)∼tn and the thermalization problem Astron. Nachr. (IF 0.9) Pub Date : 2024-01-10 Felipe Gregoletto Ben, Magno V. T. Machado
We study the energy distribution of hard gluons traversing a dense quark-gluon plasma by comparing various transverse momentum broadening rates q^(t)$$ \hat{q}(t) $$, using a probabilistic perturbative approach. These results were applied to address the thermalization problem in heavy ion collisions. Within the weak coupling model, thermalization follows a “bottom-up” process: early-formed high-energy
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The statistical characteristics of the prompt emission lightcurves of gamma-ray bursts Astron. Nachr. (IF 0.9) Pub Date : 2024-01-09 Guan-Lun Ma, Wei Xie, Wan-Kai Wang, Ai-Jun Dong, Qi-Jun Zhi
We fitted 75 pulses from 44 gamma-ray burst (GRB) prompt emission lightcurves, including four short ones and 40 long ones. Each pulse is fitted by a fast-rising exponential-decay (FRED) model. The statistical properties of these pulses are analyzed and compared with previous works. We found that the FRED model is almost suitable to describe all the pulses. We reconfirmed that there is a linear correlation
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Light vector mesons photoproduction and nuclear shadowing Astron. Nachr. (IF 0.9) Pub Date : 2024-01-09 Haimon Trebien
In this work, we study the photoproduction of ρ $$ \rho $$ mesons considering the proton and the nucleus as the target. Utilizing the dipole picture and the wave functions obtained via AdS/QCD, we were able to describe the HERA γ p $$ \gamma p $$ data and extend the formalism to the nuclear case considering the Glauber–Gribov model. The preliminary results obtained in the nuclear regime are compared
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Equation of state and anisotropy of pressure of magnetars Astron. Nachr. (IF 0.9) Pub Date : 2024-01-08 Yong-Hong Li, Wen-Qi Ma, Hui Wang
Magnetars are the neutron stars with the highest magnetic fields up to 1015–1016 G. It has been proposed that they are also responsible for a variety of extra-galactic phenomena, ranging from giant flares in nearby galaxies to fast radio bursts. Utilizing a relativistic mean field model and a variable magnetic field configuration, we investigate the effects of strong magnetic fields on the equation
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Nuclear modification factor for quarkonium production in high energy proton-nucleus collisions within the parton saturation approach Astron. Nachr. (IF 0.9) Pub Date : 2024-01-04 Érison S. Rocha, Magno V. T. Machado
In this work, we analyze nuclear effects in the inclusive production of quarkonium in proton-nucleus collisions at high energy regime. A theoretical framework that includes initial state effects like nuclear shadowing and gluon density saturation is considered. Numerical results for nuclear modification factor, RpA(y)$$ {R}_{pA}(y) $$, as a function of meson rapidity in proton-nucleus collisions
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Investigating the partonic entanglement entropy at low Bjorken-x within Gluon saturation approach Astron. Nachr. (IF 0.9) Pub Date : 2024-01-03 Gabriel Silveira Ramos, Magno V. T. Machado
In this work, the entanglement entropy is examined within the context of deep inelastic scattering in e p $$ ep $$ collisions. The calculation is based on a formalism where the partonic state at small- x $$ x $$ is maximally entangled, consisting of a large number of micro-states occurring with equal probabilities. Analytical expressions for the number of gluons, N gluon $$ {N}_{\mathrm{gluon}} $$
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Noncommutative branch-cut quantum gravity with a self-coupling inflation scalar field: Dynamical equations Astron. Nachr. (IF 0.9) Pub Date : 2024-01-02 Peter O. Hess, Fridolin Weber, Benno Bodmann, José de Freitas Pacheco, Dimiter Hadjimichef, Marcelo Netz-Marzola, Geovane Naysinger, Moisés Razeira, César A. Zen Vasconcellos
This article focuses on a recently developed formulation based on the noncommutative branch-cut cosmology, the Wheeler-DeWitt (WdW) equation, the Hořava–Lifshitz quantum gravity, chaotic and the coupling of the corresponding Lagrangian approach with the inflaton scalar field. Assuming a mini-superspace of variables obeying the noncommutative Poisson algebra, we examine the impact of the inflaton scalar
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Measuring the speed of gravity at short distances: Sensitivity estimate Astron. Nachr. (IF 0.9) Pub Date : 2024-01-02 Carlos Frajuca, Fabio da Silva Bortoli, Natan Vanelli Garcia, Nadja Simao Magalhaes
An experimental set up was proposed to determine the speed of gravitational signals traveling in air or in some other medium. It involves two vibrating masses—the emitters, which will be the sources of periodic tidal gravitational signals—and one sapphire-made mass that will act as a detector, positioned between the two emitters. The detector is planned to be suspended in vacuum and cooled down to
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Long-term stability of planetary orbits between Jupiter and Saturn Astron. Nachr. (IF 0.9) Pub Date : 2024-01-02 Rudolf Dvorak, Manfred Cuntz
We extend our two previous studies on the existence of stable orbits in the Solar System by examining the domain between Jupiter and Saturn. We place (1) a massless object, (2) a Moon-mass object, (3) a Mars-mass object, (4) an Earth-mass object, and (5) a Uranus-mass object in the said region. Note that these objects are considered separately in the framework of our simulations. Our goal is to explore
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An accretion-jet model for 3C 84: Interpreting the spectral energy distribution and Faraday rotation measure Astron. Nachr. (IF 0.9) Pub Date : 2023-12-26 Jianchao Feng, Xiaowen Wang, Rui Jing
3C 84 is a well-known supermassive black hole that can be used to explore jet and accretion physics. In this work, we model the multiwavelength spectral energy distribution (SED) of the 3C 84, and find that the SED is difficult to fit with pure advection dominated accretion flow (ADAF) or pure jet model. Using a coupled ADAF-jet model to fit the SED of 3C 84, it is found that the radio emission and
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The effects of a minimal length on the Kerr metric Astron. Nachr. (IF 0.9) Pub Date : 2023-12-26 L. Maghlaoui, P. O. Hess
The effects of a minimal length on the Kerr metric are studied within the pseudo-complex General Relativity (pcGR), which has a minimal length parameter and also depends on a r$$ r $$-dependent metric, allowing for the accumulation of dark energy around a star. The relevant parameters are the rotational Kerr parameter a$$ a $$, the mass of a black hole, and a parameter measuring the amount of dark
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The influence of quark anomalous magnetic moment in the Nambu–Jona-Lasinio model with different regularizations Astron. Nachr. (IF 0.9) Pub Date : 2023-12-26 William R. Tavares, Rodrigo M. Nunes, Sidney S. Avancini, Ricardo L. S. Farias
The Nambu–Jona-Lasinio model is known for its simplicity and capacity to reproduce some of the basic characteristics of the quantum chromodynamics phase diagram. However, since it is a nonrenormalizable model, there are regularization issues that should be treated conveniently. This is the case when considering the quark anomalous magnetic moment (AMM) when external constant magnetic fields are present
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Fulfilling modern astrophysical observations and lattice QCD constraints based on a nonlocal NJL model with 3D form factor Astron. Nachr. (IF 0.9) Pub Date : 2023-12-20 G. A. Contrera, J. P. Carlomagno, A. G. Grunfeld
In the present work, we employ a nonlocal Nambu–Jona–Lasinio (NJL) model with a Gaussian form factor that is dependent on the spatial components of the momentum (3D-FF). Focusing on the temperature-baryon chemical potential plane, we investigate some aspects of the phase diagram. Initially, we propose an assumption that the range of interactions in momentum space may be modified by temperature, allowing
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Highly magnetized quark matter in the chiral limit Astron. Nachr. (IF 0.9) Pub Date : 2023-12-17 S. A. Ferraris, J. P. Carlomagno, A. G. Grunfeld
We examine the behavior of highly magnetized two-light-flavor quark matter within the context of a nonlocal NJL-type model. This analysis assumes the chiral limit (mc=0)$$ \left({m}_c=0\right) $$ and incorporates the interaction between fermions and the Polyakov loop. Our calculations utilize a covariant Gaussian form factor. We present phase diagrams on the T−μ$$ T-\mu $$ plane, illustrating different
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Surface and curvature tensions of cold quark matter in the SU(3)f NJL model with vector interactions Astron. Nachr. (IF 0.9) Pub Date : 2023-12-14 M. F. Izzo Villafañe, G. Lugones, A. G. Grunfeld
We investigate the surface and curvature tensions of three-flavor cold quark matter in a state of electric charge neutrality and chemical equilibrium under weak interactions, employing the Nambu–Jona–Lasinio model with the inclusion of vector interactions. To account for finite-size effects we adopt the multiple-reflection expansion framework and present our results for various input parameters. Our
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Noncommutative branch-cut quantum gravity with a self-coupling inflaton scalar field: The wave function of the Universe Astron. Nachr. (IF 0.9) Pub Date : 2023-12-13 Peter O. Hess, Fridolin Weber, Benno Bodmann, José de Freitas Pacheco, Dimiter Hadjimichef, Marcelo Netz-Marzola, Geovane Naysinger, Moisés Razeira, César A. Zen Vasconcellos
This article focuses on the implications of a noncommutative formulation of branch-cut quantum gravity. Based on a mini-superspace structure that obeys the noncommutative Poisson algebra, combined with the Wheeler–DeWitt equation and Hořava–Lifshitz quantum gravity, we explore the impact of a scalar field of the inflaton-type in the evolution of the Universe's wave function. Taking as a starting point
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The branch-cut quantum gravity with a self-coupling inflation scalar field: Dynamical equations Astron. Nachr. (IF 0.9) Pub Date : 2023-12-12 Fridolin Weber, Peter O. Hess, Benno Bodmann, José de Freitas Pacheco, Dimiter Hadjimichef, Marcelo Marzola, Geovane Naysinger, Moisés Razeira, César A. Zen Vasconcellos
This article focuses on the implications of the recently developed commutative formulation based on branch-cutting cosmology, the Wheeler–DeWitt equation, and Hořava–Lifshitz quantum gravity. Assuming a mini-superspace of variables, we explore the impact of an inflaton-type scalar field ϕ ( t ) $$ \phi (t) $$ on the dynamical equations that describe the trajectories evolution of the scale factor of
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The branch-cut quantum gravity with a self-coupling inflation scalar field: The wave function of the Universe Astron. Nachr. (IF 0.9) Pub Date : 2023-12-12 Fridolin Weber, Peter O. Hess, Benno Bodmann, José de Freitas Pacheco, Dimiter Hadjimichef, Marcelo Marzola, Geovane Naysinger, Moisés Razeira, César A. Zen Vasconcellos
This paper focuses on the implications of a commutative formulation that integrates branch-cutting cosmology, the Wheeler–DeWitt equation, and Hořava–Lifshitz quantum gravity. Building on a mini-superspace structure, we explore the impact of an inflaton-type scalar field on the wave function of the Universe. Specifically analyzing the dynamical solutions of branch-cut gravity within a mini-superspace
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Exclusive production of ground and excited light vector mesons with a holographic wave function model Astron. Nachr. (IF 0.9) Pub Date : 2023-12-12 Cheryl Henkels
The exclusive photo- and electroproduction of light vector mesons like ρ,ω,$$ \rho, \omega, $$ and ϕ$$ \phi $$ is studied in γp$$ \gamma p $$ collisions within the color dipole formalism with vector meson wave functions obtained using the AdS/QCD holographic approach. This setup provides a good description of the existing data for the ground vector mesons ρ(1S),ω(1S),andϕ(1S)$$ \rho (1S),\kern0
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A short review of the pulsar magnetic inclination angles (II) Astron. Nachr. (IF 0.9) Pub Date : 2023-12-11 Biao-Peng Li, Wen-Qi Ma, Zhi-Fu Gao
The pulsar magnetic inclination angle is a key parameter for pulsar physics. It influences the observable properties of pulsars, such as the pulse beam width, braking index, polarization, and emission geometry. In this study, we give a brief overview of the current state of knowledge and research on this parameter and its implications for the internal physics of pulsars. We use the observed pulsar
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Letter from the Editor Astron. Nachr. (IF 0.9) Pub Date : 2023-12-12 Klaus G. Strassmeier
With the present first issue of volume 345 in 2024, we enter the 203rd year of continuous appearance of Astronomische Nachrichten/Astronomical Notes (AN). Not bad, even by astronomical standards. Needless to recall the changes that scientific publishing had gone through over the years and currently still is, and thus also changed AN. Myself being an active researcher/author and flooded daily with article-submission
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The isolated elliptical galaxy NGC 5812–MOND or dark matter? Astron. Nachr. (IF 0.9) Pub Date : 2023-12-12 Tom Richtler, Ricardo Salinas, Richard Lane, Michael Hilker
There exist isolated elliptical galaxies, whose dynamics can be modeled without resorting to dark matter or MOND, for example, NGC 7507. Such objects lack understanding within the current framework of galaxy formation. The isolated elliptical NGC 5812 is another object to investigate a possible role of isolation. We use globular clusters (GCs) and the galaxy light itself as dynamical tracers to constrain
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Repeating fast radio bursts reveal the secret of pulsar magnetospheric activity Astron. Nachr. (IF 0.9) Pub Date : 2023-12-05 Renxin Xu, Weiyang Wang
The puzzling mechanism of coherent radio emission remains unknown, but fortunately, repeating fast radio bursts (FRBs) provide a precious opportunity, with extremely bright subpulses created in a clear and vacuum-like pulsar magnetosphere. FRBs are millisecond-duration signals that are highly dispersed at distant galaxies but with uncertain physical origin(s). Coherent curvature radiation by bunches
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Uncertainty relation in viscous hydrodynamics and its effects in collective flow observables Astron. Nachr. (IF 0.9) Pub Date : 2023-12-03 G. Gonçalves de Matos, L. Henrique, T. Kodama, T. Koide
The uncertainty relation is considered to be one of key features of quantum mechanics which distinguishes quantum and classical systems. Recently, we developed a new formulation of the uncertainty relation based on the generalized scheme of variational principle, the stochastic variational method (SVM). In this method, the uncertainty relation is related to the nondifferentiability of observables and
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Differential rotation in compact objects with hyperons and delta isobars Astron. Nachr. (IF 0.9) Pub Date : 2023-12-03 Delaney Farrell, Fridolin Weber, Jia Jie Li, Armen Sedrakian
Neutron stars may experience differential rotation on short, dynamical timescales following extreme astrophysical events like binary neutron star mergers. In this work, the masses and radii of differentially rotating neutron star models are computed. We employ a set of equations of states for dense hypernuclear and Δ $$ \Delta $$ -admixed-hypernuclear matter obtained within the framework of CDF theory
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Circumstellar disk and the first generation of stars Astron. Nachr. (IF 0.9) Pub Date : 2023-12-03 Rafeel Riaz
Circumstellar disk (CD) around the first generation of stars have been numerically investigated here to see if the cooling regimes also play a role in the formation and evolution of the disk associated with the most massive protostars (MMPS). Also, an emphasis is given to exploring the effect of the initial turbulent motion of the metal-free gas on the resulting morphology of the CD. For this, a systematic
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Decomposition of the central structure of NGC 2273 in the NIR: A case study Astron. Nachr. (IF 0.9) Pub Date : 2023-11-27 L. Schey, J. Heidt, A. Pramskiy, D. Thompson, G. Agapito, S. Esposito, R. Gredel, D. Miller, E. Pinna, A. Puglisi, F. Rossi, W. Seifert, G. Taylor, A. Quirrenbach
The Seyfert 2 galaxy NGC 2273 is a prime target to explore how active nuclei can be fed. It has a star-forming innermost nuclear ring with a radius of 0.33kpc from where material may be funneled to the supermassive black hole in its center. In this article, we discuss high-resolution adaptive optics aided JHKs images of NGC 2273 taken with the Large Binocular Telescope. Using Galfit we decomposed the
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Possible stellar asterisms carved on a protohistoric stone Astron. Nachr. (IF 0.9) Pub Date : 2023-11-22 Paolo Molaro, Federico Bernardini
Chisel marks on a stone uncovered in Rupinpiccolo protohistoric hill fort from north-eastern Italy were suggested to be a representation of the night sky (Bernardini et al. 2022 Documenta Praehistorica XLIX). The patterns of the 29 marks are analyzed here to establish if they reproduce popular stellar asterisms. Nine marks are found to match the Tail of Scorpius and five the Orion's Belt, together
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Solid-state curved focal plane arrays realized with simple approaches for compact and high-performance optical systems Astron. Nachr. (IF 0.9) Pub Date : 2023-11-14 Shouleh Nikzad, Todd J. Jones, Michael E. Hoenk, Paul von Allmen
We present an overview of our work on design, development, and demonstration of simple and effective approaches to fabricating solid-state curved focal plane arrays (CFPAs) that have spawned a novel class of detector arrays. CFPAs can dramatically alter the capability and size of image systems, with an especially high impact in scientific and space applications in terms of science-instrument size,