Astronomische Nachrichten最新文献

{"title":"Equation of state and anisotropy of pressure of magnetars","authors":"Yong-Hong Li,&nbsp;Wen-Qi Ma,&nbsp;Hui Wang","doi":"10.1002/asna.20230180","DOIUrl":"10.1002/asna.20230180","url":null,"abstract":"<p>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 of state and anisotropy of pressure of magnetars. It is found that the mass and radius of low-mass magnetars are weakly enhanced under the action of the strong magnetic field, and the anisotropy of pressure can be ignored. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139415489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nuclear modification factor for quarkonium production in high energy proton-nucleus collisions within the parton saturation approach","authors":"Érison S. Rocha,&nbsp;Magno V. T. Machado","doi":"10.1002/asna.20230165","DOIUrl":"10.1002/asna.20230165","url":null,"abstract":"<p>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, <math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>R</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>p</mi>\u0000 <mi>A</mi>\u0000 </mrow>\u0000 </msub>\u0000 <mo>(</mo>\u0000 <mi>y</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$$ {R}_{pA}(y) $$</annotation>\u0000 </semantics></math>, as a function of meson rapidity in proton-nucleus collisions are presented. The parameter-free predictions are compared to the available data from the Large Hadron Collider. Discussion on the main theoretical uncertainties is made, with emphasis on the phenomenological models for the nuclear saturation scale.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139095794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the partonic entanglement entropy at low Bjorken-x within Gluon saturation approach","authors":"Gabriel Silveira Ramos,&nbsp;Magno V. T. Machado","doi":"10.1002/asna.20230173","DOIUrl":"10.1002/asna.20230173","url":null,"abstract":"<p>In this work, the entanglement entropy is examined within the context of deep inelastic scattering in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>e</mi>\u0000 <mi>p</mi>\u0000 </mrow>\u0000 <annotation>$$ ep $$</annotation>\u0000 </semantics></math> collisions. The calculation is based on a formalism where the partonic state at small-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>x</mi>\u0000 </mrow>\u0000 <annotation>$$ x $$</annotation>\u0000 </semantics></math> is maximally entangled, consisting of a large number of micro-states occurring with equal probabilities. Analytical expressions for the number of gluons, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>N</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mtext>gluon</mtext>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {N}_{mathrm{gluon}} $$</annotation>\u0000 </semantics></math>, are considered, derived from gluon saturation models for dipole-target amplitudes within the framework of the Quantum Chromodynamics (QCD) color dipole picture. A comparison of the entanglement entropy with thermodynamic entropy measured in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>p</mi>\u0000 <mi>p</mi>\u0000 </mrow>\u0000 <annotation>$$ pp $$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>e</mi>\u0000 <mi>p</mi>\u0000 </mrow>\u0000 <annotation>$$ ep $$</annotation>\u0000 </semantics></math> collisions at high energies is done.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139095616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term stability of planetary orbits between Jupiter and Saturn","authors":"Rudolf Dvorak,&nbsp;Manfred Cuntz","doi":"10.1002/asna.20230147","DOIUrl":"10.1002/asna.20230147","url":null,"abstract":"<p>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 the orbital stability of those objects. We employ the Lie-integration method, which is fast and well established, allowing us to solve the respective differential equations for the <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>N</mi>\u0000 </mrow>\u0000 <annotation>$$ N $$</annotation>\u0000 </semantics></math>-body system. Hence, we consider the celestial bodies spanning from Jupiter to Neptune, including the aforementioned test object, the main focus for our model simulations. The integrations indicate that in some models the test objects placed in the region between Jupiter and Saturn reside in that region for more than 600 Myr. Between 5 and 10 au, mean-motion resonances (MMRs) take place acting upon the test objects akin to simulations of Paper I and II. Our models indicate relatively small differences for the long-term stability of the five test objects notwithstanding their vastly different masses. Generally, it is found that between <math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>a</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mtext>ini</mtext>\u0000 </mrow>\u0000 </msub>\u0000 <mo>=</mo>\u0000 <mn>7</mn>\u0000 <mo>.</mo>\u0000 <mn>04</mn>\u0000 </mrow>\u0000 <annotation>$$ {a}_{mathrm{ini}}=7.04 $$</annotation>\u0000 </semantics></math> and 7.13 au the orbits become unstable mostly within 5 million years and further out, that is, up to <math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>a</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mtext>ini</mtext>\u0000 </mrow>\u0000 </msub>\u0000 <mo>=</mo>\u0000 <mn>7</mn>\u0000 <mo>.</mo>\u0000 <mn>29</mn>\u0000 </mrow>\u0000 <annotation>$$ {a}_{mathrm{ini}}=7.29 $$</annotation>\u0000 </semantics></math> au, the duration of stability lengthens to up to hundreds of millions of years.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139374075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Noncommutative branch-cut quantum gravity with a self-coupling inflation scalar field: Dynamical equations","authors":"Peter O. Hess,&nbsp;Fridolin Weber,&nbsp;Benno Bodmann,&nbsp;José de Freitas Pacheco,&nbsp;Dimiter Hadjimichef,&nbsp;Marcelo Netz-Marzola,&nbsp;Geovane Naysinger,&nbsp;Moisés Razeira,&nbsp;César A. Zen Vasconcellos","doi":"10.1002/asna.20230171","DOIUrl":"10.1002/asna.20230171","url":null,"abstract":"<p>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 field on the evolutionary dynamics of the branch-cut Universe scale factor, characterized by the dimensionless helix-like function <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>ln</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 <mrow>\u0000 <mo>[</mo>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mi>t</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <mo>]</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation>$$ {ln}^{-1}left[beta (t)right] $$</annotation>\u0000 </semantics></math>. This scale factor characterizes a Riemannian foliated spacetime that topologically overcomes the primordial singularities. We take the Hořava–Lifshitz action modeled by branch-cut quantum gravity as our starting point, which depends on the scalar curvature of the branched Universe and its derivatives and which preserves the diffeomorphism property of General Relativity, maintaining compatibility with the Arnowitt–Deser–Misner formalism. We then investigate the sensitivity of the scale factor of the branch-cut Universe's dynamics.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139095925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring the speed of gravity at short distances: Sensitivity estimate","authors":"Carlos Frajuca,&nbsp;Fabio da Silva Bortoli,&nbsp;Natan Vanelli Garcia,&nbsp;Nadja Simao Magalhaes","doi":"10.1002/asna.20230177","DOIUrl":"10.1002/asna.20230177","url":null,"abstract":"<p>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 4.2 K, and its vibrational amplitude should be measured by a microwave signal (with ultra-low phase-noise) that is expected to resonate with the whispering gallery modes inside the detector. The mechanical and electrical quality factors of sapphire are quite high, yielding a very narrow detection band that reduces the detector sensitivity while amplifying the phase difference of the emitters' signals. The frequencies of the normal modes of the detector were previously determined using a finite element program. In this work, these frequencies are applied to the calculation of a first estimate of the sensitivity of the experiment.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139095619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Teledyne imaging sensors' recent contributions to astronomy, earth science, and planetary science","authors":"James W. Beletic,&nbsp;John Auyeung,&nbsp;Jianmei Pan,&nbsp;Liz Corrales,&nbsp;Meghan Dorn,&nbsp;Devraj Maitra,&nbsp;Mark Farris,&nbsp;Majid Zandian,&nbsp;Eric Piquette,&nbsp;Liz Rangel,&nbsp;Anders Petersen,&nbsp;Aristo Yulius,&nbsp;Yibin Bai,&nbsp;Sid Bhargava","doi":"10.1002/asna.20230136","DOIUrl":"https://doi.org/10.1002/asna.20230136","url":null,"abstract":"<p>Teledyne Imaging Sensors (TIS) is the leading supplier of infrared focal plane arrays (FPAs) to astronomy and TIS plays a strong role in providing image sensors for Earth and Planetary Science. This article starts with a brief introduction to TIS' technologies and image sensor products. We then present some of TIS' deliveries to space missions and ground-based telescopes. The space missions include ESA's Euclid Dark Universe mission and several NASA missions (James Webb Space Telescope, Roman Space Telescope, SPHEREx, EMIT). TIS continues to serve ground-based astronomy by providing the H2RG and the world's largest high-performance infrared astronomy FPA, the H4RG-15, to several ground-based observatories. Active programs will be described. Ongoing work includes NASA's NEO Surveyor asteroid surveillance mission, ESA's Ariel exo-planet spectroscopy mission, and deliveries to the European Southern Observatory's Extremely Large Telescope.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"344 8-9","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139047289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An accretion-jet model for 3C 84: Interpreting the spectral energy distribution and Faraday rotation measure","authors":"Jianchao Feng,&nbsp;Xiaowen Wang,&nbsp;Rui Jing","doi":"10.1002/asna.20230175","DOIUrl":"10.1002/asna.20230175","url":null,"abstract":"<p>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 the millimeter emission can be naturally reproduced by the synchrotron radiation of nonthermal electrons in the jet, and that the X-ray emission may predominantly come from inverse Compton radiation from electrons in ADAF. According to the Rotation Measure (RM) obtained by the polarization observation, we consider the possible location of the polarizing source and found that the calculated RM in the jet is roughly consistent with the observational constraints. These results will help us better understand jets produced by black holes.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139054767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of quark anomalous magnetic moment in the Nambu–Jona-Lasinio model with different regularizations","authors":"William R. Tavares,&nbsp;Rodrigo M. Nunes,&nbsp;Sidney S. Avancini,&nbsp;Ricardo L. S. Farias","doi":"10.1002/asna.20230168","DOIUrl":"10.1002/asna.20230168","url":null,"abstract":"<p>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. Regularization procedures based on entangled functions between the magnetic field and the cutoff of the model can predict first-order phase transitions for chiral symmetry restoration at finite values of magnetic fields and inverse magnetic catalysis. The strengths of magnetic fields explored in NJL model and lattice QCD do not show first-order phase transition. In the present work, we show that some of the previous results are regularization-dependent effects and how to handle the divergences using the vacuum magnetic regularization scheme.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139054876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of a minimal length on the Kerr metric","authors":"L. Maghlaoui,&nbsp;P. O. Hess","doi":"10.1002/asna.20230151","DOIUrl":"10.1002/asna.20230151","url":null,"abstract":"<p>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 <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>r</mi>\u0000 </mrow>\u0000 <annotation>$$ r $$</annotation>\u0000 </semantics></math>-dependent metric, allowing for the accumulation of dark energy around a star. The relevant parameters are the rotational Kerr parameter <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>a</mi>\u0000 </mrow>\u0000 <annotation>$$ a $$</annotation>\u0000 </semantics></math>, the mass of a black hole, and a parameter measuring the amount of dark energy accumulated. It is found that the metric is modified by a factor, depending on <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>r</mi>\u0000 </mrow>\u0000 <annotation>$$ r $$</annotation>\u0000 </semantics></math>, resulting in a maximal acceleration. This factor shows several singularities. For small black holes, the corresponding effective potentials exhibit potential barriers, avoiding the increase of the black hole's mass. It is found that the effects of a minimal length are only of importance for very small mass black holes and vanish for macroscopic black holes.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}