Astronomische Nachrichten最新文献

{"title":"Anisotropy in Magnetized Quark Matter in the Chiral Limit","authors":"Sebastian Alberto Ferraris,&nbsp;Juan Pablo Carlomagno,&nbsp;Gustavo Anibal Gabriel Contrera,&nbsp;Ana Gabriela Grunfeld","doi":"10.1002/asna.20250020","DOIUrl":"https://doi.org/10.1002/asna.20250020","url":null,"abstract":"<div>\u0000 \u0000 <p>We investigate the behavior of cold quark matter under strong magnetic fields in the frame of a nonlocal NJL model in the chiral limit. Our analysis focuses on deconfinement, chiral symmetry restoration, and the anisotropy in pressure induced by the external magnetic field. For <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>eB</mi>\u0000 <mo>≲</mo>\u0000 <mn>0.07</mn>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>GeV</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ eBlesssim 0.07kern0.22em {mathrm{GeV}}^2 $$</annotation>\u0000 </semantics></math>, the critical chemical potential remains largely insensitive to the magnetic field, whereas at higher field strengths, transitions to chirally restored phases occur at progressively lower chemical potentials. The parallel and perpendicular pressures, with respect to the magnetic field, exhibit distinct behaviors, reflecting the anisotropic nature of the system. Oscillations in the quark number density, driven by the de Haas–van Alphen effect, reflect the quantized behavior of quarks in a magnetic field. Similarly, the magnetization displays oscillatory behavior, driven by the sequential filling of Landau levels (LLs). At lower external magnetic field strengths, contributions from orbital angular momentum and the population of higher LLs further modulate these oscillations. These results provide deeper insights into the thermodynamic and magnetic properties of quark matter under strong magnetic fields, with implications for astrophysical studies.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207083","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":"Issue Information: Astron. Nachr. 2/2025","authors":"","doi":"10.1002/asna.20259002","DOIUrl":"https://doi.org/10.1002/asna.20259002","url":null,"abstract":"","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20259002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cover Picture: Astron. Nachr. 2/2025","authors":"Iva Vilović,&nbsp;Jayesh Goyal,&nbsp;René Heller,&nbsp;Fanny Marie von Schauenburg","doi":"10.1002/asna.20259011","DOIUrl":"https://doi.org/10.1002/asna.20259011","url":null,"abstract":"<p>Simulated differential transmission spectra of various “superhabitable” planet scenarios. For comparison, the predicted spectra of Kepler-62e (a terrestrial planet in the habitable zone of a K dwarf) and the modern Earth around the Sun are shown as well. Spectral features are displayed in ppm relative to each planet's baseline transit depth, revealing individual molecular signatures, including O₂, O₃, CH₄, H₂O, N₂O, CO₂, CH₃Cl, and CO. Solid gray lines represent planets receiving an incident stellar flux of 0.8 solar constants (<i>S</i>0 = 1366 W/m²), positioned between the inner edge and center of their respective host star's habitable zone, while dashed lines represent the same planets at 0.6 <i>S</i>0, aligned with the center of the habitable zone. The prospects of observing possible biosignatures in the atmospheres of transiting “superhabitable” exoplanets with the James Webb Space Telescope are discussed in the related paper by I. Vilović et al. published in this issue e20240081.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20259011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the Evolution of Compact Object Populations","authors":"J. E. Horvath,&nbsp;L. M. de Sá,&nbsp;L. S. Rocha,&nbsp;N. D. Pires,&nbsp;R. Miwa,&nbsp;D. Rodrigues,&nbsp;L. G. Barão,&nbsp;G. Y. Chinen,&nbsp;The GARDEL Group","doi":"10.1002/asna.20250018","DOIUrl":"https://doi.org/10.1002/asna.20250018","url":null,"abstract":"<div>\u0000 \u0000 <p>The population of compact objects both Galactic and extragalactic can now be studied and verified observationally with increasing efficiency, the latter thanks to the detection of compact object mergers through gravitational waves. The formation channels of merging compact object binaries are, however, not yet fully understood, and may even vary over cosmic time. We address this problem with a population synthesis approach, including BOSSA, a new initial sampling code, to deal with the variation of initial conditions and evaluate its consequences.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206970","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":"Reviewing the GR Method for Estimating Black Hole Parameters of Megamaser Systems","authors":"Adriana González-Juárez,&nbsp;Alfredo Herrera-Aguilar","doi":"10.1002/asna.20250016","DOIUrl":"https://doi.org/10.1002/asna.20250016","url":null,"abstract":"<div>\u0000 \u0000 <p>We review a general relativistic (GR) method to determine the black hole (BH) parameters: Mass-to-distance ratio, position, and recessional velocity of 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 aforementioned masers and their orbital position on the sky. In order to perform the estimations we implement a Bayesian statistical method to fit the above mentioned observational data. One of the main results of this work consists in analytically expressing the gravitational redshift, allowing us to quantify its magnitude for the photons emitted by the closest masers to the black holes. We present this quantity for several BHs hosted at the core of AGNs.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207074","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":"Enhanced Kinematics and Distribution Characteristics of Upper Scorpius and Ophiuchus Associations Based on Gaia DR3","authors":"W. H. Elsanhoury","doi":"10.1002/asna.20240082","DOIUrl":"https://doi.org/10.1002/asna.20240082","url":null,"abstract":"<div>\u0000 \u0000 <p>The kinematics within the solar vicinity have revealed interesting features relevant to both stellar and Galactic structures. This study examines three stellar associations in the Upper Scorpius and Ophiuchus regions, along with their sub-samples among Gaia DR3. The calculated kinematics and velocity ellipsoid characteristics, including the mean spatial velocity components (<i>U</i>, <i>V</i>, and <i>W</i>; km s⁻¹), yielding values of approximately (−5.84 ± 2.42, −16.14 ± 4.02, −7.31 ± 2.70; km s⁻¹). USC and Oph associations velocity dispersion within the ellipsoid (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>σ</mi>\u0000 <mi>i</mi>\u0000 </msub>\u0000 <mo>,</mo>\u0000 <mo>∀</mo>\u0000 <mi>i</mi>\u0000 <mo>=</mo>\u0000 <mn>1</mn>\u0000 <mo>,</mo>\u0000 <mn>2</mn>\u0000 <mo>,</mo>\u0000 <mn>3</mn>\u0000 </mrow>\u0000 <annotation>$$ {sigma}_i,forall i=1,2,3 $$</annotation>\u0000 </semantics></math>) was found to be (1.36 ± 0.02, 0.80 ± 0.01, 0.96 ± 0.01; km s⁻¹), their mean solar motion (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>S</mi>\u0000 <mo>⊙</mo>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {S}_{odot } $$</annotation>\u0000 </semantics></math>) was determined to be approximately 18.62 ± 4.32 km s⁻¹, convergent point coordinates (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>A</mi>\u0000 <mi>o</mi>\u0000 </msub>\u0000 <mo>,</mo>\u0000 <msub>\u0000 <mi>D</mi>\u0000 <mi>o</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {A}_{mathrm{o}},{D}_{mathrm{o}} $$</annotation>\u0000 </semantics></math>) were (95.91 ± 0.09°, −44.42 ± 0.02°), and Oort's constants, yielding <i>A</i> = 17.80 ± 0.24 km s⁻¹ kpc⁻¹ and <i>B</i> = −9.61 ± 0.32 km s⁻¹ kpc⁻¹. Finally, the density distribution function per absolute magnitudes of USC and Oph associations is examined to obtain both luminosity and mass functions; their analysis revealed the absence of any peaks or dips as consistent with other recent studies.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489860","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":"Analysis of a q-Deformed Covariant Algebra With the Fock-Tani Formalism","authors":"Ramiro R. B. de Souza,&nbsp;Dimiter Hadjimichef,&nbsp;César A. Zen Vasconcellos","doi":"10.1002/asna.20250009","DOIUrl":"https://doi.org/10.1002/asna.20250009","url":null,"abstract":"<div>\u0000 \u0000 <p>Motivated by the difficulties in the quantization of spacetime, we study a q-deformed covariant algebra that imposes minimum position and momentum measurement uncertainties. We do this by invoking the Fock-Tani formalism, mainly used in atomic and nuclear physics. The results are promising for further calculation of physical predictions.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206695","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":"Detection of Eclipses in the Cataclysmic Variable LAMOST J035913.61 + 405035.0","authors":"V. P. Kozhevnikov","doi":"10.1002/asna.20240124","DOIUrl":"https://doi.org/10.1002/asna.20240124","url":null,"abstract":"<div>\u0000 \u0000 <p>I conducted photometric observations of the cataclysmic variable LAMOST J035913.61 + 405035.0 and detected eclipses. During these observations, I recorded 14 eclipses over two groups of nights separated by 13 months. I accurately determined the orbital period of the system to be <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>P</mi>\u0000 <mi>orb</mi>\u0000 </msub>\u0000 <mo>=</mo>\u0000 <mn>0.228</mn>\u0000 <mspace></mspace>\u0000 <mn>343</mn>\u0000 <mspace></mspace>\u0000 <mn>85</mn>\u0000 <mo>±</mo>\u0000 <mn>0.000</mn>\u0000 <mspace></mspace>\u0000 <mn>000</mn>\u0000 <mspace></mspace>\u0000 <mn>21</mn>\u0000 </mrow>\u0000 <annotation>$$ {P}_{mathrm{orb}}=0.228kern0.1em 343kern0.1em 85pm 0.000kern0.1em 000kern0.1em 21 $$</annotation>\u0000 </semantics></math> days. For the eclipses, I derived an ephemeris which is valid for a long time and suitable for studying changes in the orbital period. The out-of-eclipse magnitude of the star varied between 15.32 ± 0.02 and 17.25 ± 0.08 mag. As the brightness decreased, the eclipses became deeper and narrower. The average depth of eclipses was 1.35 ± 0.10 mag, and the average width at half-depth was 16.9 ± 0.7 min. I estimated the range of possible orbital inclinations to be between 72.8° and 76.0°, and the range of average absolute <i>V</i>-band magnitudes of the disc to be between 5.16 ± 0.15 and 5.44 ± 0.15 mag. Although based on the light curve from the ZTF survey, LAMOST J035913.61 + 405035.0 showed only small outbursts with amplitudes below 1.5 mag, it should be classified as a dwarf nova because the average disc brightness and mass transfer rate were below the limit of thermal instability.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489840","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":"Holonomy Observables for the Turaev–Viro Model of Quantum Gravity","authors":"V. M. G. Silveira,&nbsp;D. Hadjimichef,&nbsp;E. G. S. Luna,&nbsp;César A. Zen Vasconcellos","doi":"10.1002/asna.20250010","DOIUrl":"https://doi.org/10.1002/asna.20250010","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper presents a proposal for the study of holonomy observables for the Turaev–Viro model, a model of three-dimensional Loop Quantum Gravity with a positive cosmological constant. A review of central aspects of Loop Quantum Gravity and of a categorical formalism for discrete gauge theories is presented with the intent to contextualize the Turaev–Viro model within a more general setting, which clarifies the role of the Hopf algebra <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>sl</mi>\u0000 <mi>q</mi>\u0000 </msub>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mn>2</mn>\u0000 <mo>,</mo>\u0000 <mi>ℂ</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation>$$ {mathfrak{sl}}_qleft(2,mathrm{mathbb{C}}right) $$</annotation>\u0000 </semantics></math> in its construction. The key results on spin observables for the Turaev–Viro model and on holonomy observables for the Ponzano–Regge model are presented as an effort to develop a theory of holonomy observables for the Turaev–Viro model.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206793","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":"Issue Information: Astron. Nachr. 1/2025","authors":"","doi":"10.1002/asna.20259001","DOIUrl":"https://doi.org/10.1002/asna.20259001","url":null,"abstract":"","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20259001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}