M. Scardia, J.-L. Prieur, J.-P. Rivet, D. Vernet, E. Aristidi, J. F. Ling, L. Piccotti, L. Pansecchi, R. W. Argyle, L. Abe, P. Bendjoya, L. Maccarini
New orbits of long period visual binary systems A 1913AB, P ≈ 3360 yr (a), A 1710, P ≈ 111 yr (b), COU1394, P ≈ 330 yr (c), BU1185, P ≈ 28 yr (d), A 122, P ≈ 103 yr (e), and A 570, P ≈ 30 yr (f). The observational data used for the calculation of the orbital elements are plotted as small green crosses or red dots, the latter indicating the new positions derived from observations with the Pupil Interferometry Speckle camera and Coronograph (PISCO) at Calern, France. For each object, the location of the primary component is indicated with a big cross; the dashed straight line going through this point is the apsidal line. This work is a valuable contribution to the continuing monitoring of long period visual binary systems, which is important for refining systemic stellar masses. For details see the paper by M. Scardia et al., e70000.
长周期视双星系统A 1913AB， P≈3360 yr (A), A 1710, P≈111 yr (b), COU1394, P≈330 yr (c), BU1185, P≈28 yr (d), A 122, P≈103 yr (e), A 570, P≈30 yr (f)的新轨道。用于计算轨道要素的观测数据用小绿叉或红点表示，后者表示由法国卡伦的瞳孔干涉散斑相机和日冕仪（PISCO）观测得出的新位置。对于每个物体，主分量的位置用一个大叉表示；经过这一点的虚线就是横横线。这项工作对长周期视觉双星系统的持续监测是一个有价值的贡献，这对精炼系统恒星质量是重要的。详见M. Scardia等人的论文，e70000。
{"title":"Cover Picture: Astron. Nachr. 6/2025","authors":"M. Scardia, J.-L. Prieur, J.-P. Rivet, D. Vernet, E. Aristidi, J. F. Ling, L. Piccotti, L. Pansecchi, R. W. Argyle, L. Abe, P. Bendjoya, L. Maccarini","doi":"10.1002/asna.70044","DOIUrl":"https://doi.org/10.1002/asna.70044","url":null,"abstract":"<p>New orbits of long period visual binary systems <i>A 1913AB</i>, P ≈ 3360 yr (a), <i>A 1710</i>, P ≈ 111 yr (b), <i>COU1394</i>, P ≈ 330 yr (c), <i>BU1185</i>, P ≈ 28 yr (d), <i>A 122</i>, P ≈ 103 yr (e), and <i>A 570</i>, P ≈ 30 yr (f). The observational data used for the calculation of the orbital elements are plotted as small green crosses or red dots, the latter indicating the new positions derived from observations with the Pupil Interferometry Speckle camera and Coronograph (PISCO) at Calern, France. For each object, the location of the primary component is indicated with a big cross; the dashed straight line going through this point is the apsidal line. This work is a valuable contribution to the continuing monitoring of long period visual binary systems, which is important for refining systemic stellar masses. For details see the paper by M. Scardia et al., e70000.\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 6","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.70044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843653","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}
L. R. Bedin, R. Gerasimov, A. Calamida, M. Libralato, M. Scalco, D. Nardiello, M. Griggio, D. Apai, J. Anderson, A. Bellini, A. Burgasser
<p>We present <i>James Webb Space Telescope</i> observations of M 4—the closest globular cluster—that probe the lower Main Sequence down to the hydrogen-burning limit. The unveiled stellar sequence reaches much fainter luminosities than previously possible, revealing a few extremely red objects that are consistent with brown dwarfs as cool as <span></span><math> <semantics> <mrow> <msub> <mi>T</mi> <mi>eff</mi> </msub> <mo>∼</mo> <mn>1000</mn> <mspace></mspace> <mi>K</mi> </mrow> <annotation>$$ {T}_{mathrm{eff}}sim 1000kern0.5em mathrm{K} $$</annotation> </semantics></math>. However, the lack of a second <i>JWST</i> epoch presently prevents us from verifying the cluster membership of these objects. By cross-matching our data with archival <i>Hubble Space Telescope</i> images, we are able to verify cluster membership for a subset of objects down to <span></span><math> <semantics> <mrow> <msub> <mi>T</mi> <mi>eff</mi> </msub> <mo>∼</mo> <mn>3000</mn> <mspace></mspace> <mi>K</mi> </mrow> <annotation>$$ {T}_{mathrm{eff}}sim 3000kern0.5em mathrm{K} $$</annotation> </semantics></math>. The observed color distribution indicate that the lower Main Sequence of M 4 is likely deficient in oxygen compared to its higher-mass post-Main Sequence members by <span></span><math> <semantics> <mrow> <mo>∼</mo> <mn>0.5</mn> <mspace></mspace> <mi>dex</mi> </mrow> <annotation>$$ sim 0.5kern0.5em mathrm{dex} $$</annotation> </semantics></math>. This feature has now been observed in three different globular clusters (M 4, NGC 6397 and 47 Tuc), suggesting a general trend. Finally, we derive the mass function of the Galactic bulge in the background of M 4. The mass function was found to have the bottom-heavy slope of <span></span><math> <semantics> <mrow> <mi>α</mi> <mo>=</mo> <mn>0.88</mn> <mo>±</mo> <mn>0.36</mn> </mrow> <annotation>$$ alpha =0.88pm 0.36 $$</annotation> </semantics></math> and appears to terminate at <span></span><math> <semantics> <mrow> <mo>∼</mo> <mn>0.15</mn> <mspace></mspace> <m
我们展示了詹姆斯·韦伯太空望远镜对m4的观测，它是最近的球状星团，探测了主序的下端，直到氢燃烧的极限。揭开的恒星序列达到了比以前可能的微弱得多的亮度，揭示了一些极红的物体，它们与温度为T ～ 1000 K $$ {T}_{mathrm{eff}}sim 1000kern0.5em mathrm{K} $$的褐矮星一致。然而，由于缺少第二个JWST纪元，目前我们无法验证这些对象的集群成员关系。通过将我们的数据与存档的哈勃太空望远镜图像交叉匹配，我们能够验证物体子集的集群成员资格，直到T ^ f ～ 3000 K $$ {T}_{mathrm{eff}}sim 3000kern0.5em mathrm{K} $$。观察到的颜色分布表明，m4主序列下部的氧含量可能比其高质量的主序列后成员低约0.5个指数$$ sim 0.5kern0.5em mathrm{dex} $$。这一特征现在已经在三个不同的球状星团（m4， NGC 6397和Tuc 47）中被观察到，这表明了一个总的趋势。最后，我们导出了银河系凸起在m4背景下的质量函数。发现质量函数的底重斜率为α = 0.88±0.36 $$ alpha =0.88pm 0.36 $$，似乎终止于～ 0.15 M⊙$$ sim 0.15kern0.5em {mathrm{M}}_{odot } $$，尽管由于样本量有限，后一个值可能被高估。
{"title":"JWST Imaging of the Closest Globular Clusters—VI. The Lowest-Mass Objects in M 4 and the Galactic Bulge","authors":"L. R. Bedin, R. Gerasimov, A. Calamida, M. Libralato, M. Scalco, D. Nardiello, M. Griggio, D. Apai, J. Anderson, A. Bellini, A. Burgasser","doi":"10.1002/asna.70042","DOIUrl":"https://doi.org/10.1002/asna.70042","url":null,"abstract":"<p>We present <i>James Webb Space Telescope</i> observations of M 4—the closest globular cluster—that probe the lower Main Sequence down to the hydrogen-burning limit. The unveiled stellar sequence reaches much fainter luminosities than previously possible, revealing a few extremely red objects that are consistent with brown dwarfs as cool as <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>T</mi>\u0000 <mi>eff</mi>\u0000 </msub>\u0000 <mo>∼</mo>\u0000 <mn>1000</mn>\u0000 <mspace></mspace>\u0000 <mi>K</mi>\u0000 </mrow>\u0000 <annotation>$$ {T}_{mathrm{eff}}sim 1000kern0.5em mathrm{K} $$</annotation>\u0000 </semantics></math>. However, the lack of a second <i>JWST</i> epoch presently prevents us from verifying the cluster membership of these objects. By cross-matching our data with archival <i>Hubble Space Telescope</i> images, we are able to verify cluster membership for a subset of objects down to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>T</mi>\u0000 <mi>eff</mi>\u0000 </msub>\u0000 <mo>∼</mo>\u0000 <mn>3000</mn>\u0000 <mspace></mspace>\u0000 <mi>K</mi>\u0000 </mrow>\u0000 <annotation>$$ {T}_{mathrm{eff}}sim 3000kern0.5em mathrm{K} $$</annotation>\u0000 </semantics></math>. The observed color distribution indicate that the lower Main Sequence of M 4 is likely deficient in oxygen compared to its higher-mass post-Main Sequence members by <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>0.5</mn>\u0000 <mspace></mspace>\u0000 <mi>dex</mi>\u0000 </mrow>\u0000 <annotation>$$ sim 0.5kern0.5em mathrm{dex} $$</annotation>\u0000 </semantics></math>. This feature has now been observed in three different globular clusters (M 4, NGC 6397 and 47 Tuc), suggesting a general trend. Finally, we derive the mass function of the Galactic bulge in the background of M 4. The mass function was found to have the bottom-heavy slope of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>α</mi>\u0000 <mo>=</mo>\u0000 <mn>0.88</mn>\u0000 <mo>±</mo>\u0000 <mn>0.36</mn>\u0000 </mrow>\u0000 <annotation>$$ alpha =0.88pm 0.36 $$</annotation>\u0000 </semantics></math> and appears to terminate at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>0.15</mn>\u0000 <mspace></mspace>\u0000 <m","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 9","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.70042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145476384","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}
The paper first meticulously analyzes the primary mechanisms of neutrino generation within neutron stars, namely the direct Urca process and the modified Urca process, elucidates the computational methods for neutrino radiation rates, including the physical mechanisms of weak interactions, applications of quantum field theory, and complex mathematical integration techniques. Additionally, it comprehensively investigates various critical factors affecting neutron star cooling processes, such as the inhibitory effect of superfluidity and superconductivity on neutrino emission rates, the anisotropic impact of strong magnetic fields on neutrino radiation, the modulating effect of baryon density on neutrino emission rates, and how these factors alter the cooling curves and observational characteristics of neutron stars. Finally, based on the existing research findings, the paper outlines future research directions in the field of neutron star thermal evolution, emphasizing the importance of enhancing the measurement accuracy of neutron star cooling curves, delving into neutrino radiation mechanisms under extreme physical conditions, and exploring potential new physical phenomena within neutron stars, such as quark matter. These studies will not only refine the physical models of neutron stars but also propel the broader field of astrophysics, offering new perspectives and insights into extreme physical conditions and fundamental interactions in the universe.
{"title":"On the Neutrino Radiation of Neutron Stars","authors":"Yong-Hong Li, Die Xu, Hui Wang","doi":"10.1002/asna.70038","DOIUrl":"https://doi.org/10.1002/asna.70038","url":null,"abstract":"<div>\u0000 \u0000 <p>The paper first meticulously analyzes the primary mechanisms of neutrino generation within neutron stars, namely the direct Urca process and the modified Urca process, elucidates the computational methods for neutrino radiation rates, including the physical mechanisms of weak interactions, applications of quantum field theory, and complex mathematical integration techniques. Additionally, it comprehensively investigates various critical factors affecting neutron star cooling processes, such as the inhibitory effect of superfluidity and superconductivity on neutrino emission rates, the anisotropic impact of strong magnetic fields on neutrino radiation, the modulating effect of baryon density on neutrino emission rates, and how these factors alter the cooling curves and observational characteristics of neutron stars. Finally, based on the existing research findings, the paper outlines future research directions in the field of neutron star thermal evolution, emphasizing the importance of enhancing the measurement accuracy of neutron star cooling curves, delving into neutrino radiation mechanisms under extreme physical conditions, and exploring potential new physical phenomena within neutron stars, such as quark matter. These studies will not only refine the physical models of neutron stars but also propel the broader field of astrophysics, offering new perspectives and insights into extreme physical conditions and fundamental interactions in the universe.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 7-8","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135490","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}
Solar activity can be witnessed in the form of sunspots and active regions, where the magnetic field is enhanced by up to a factor of 1000 as compared to that of the quiet Sun. In addition, solar activity manifests itself in terms of flares, jets, coronal mass ejections and the production of highly energetic particles. All these processes are governed by the solar magnetic field. Here we study the spatial reach of the influence of the magnetic field of active regions on the photosphere and in the solar corona. An active region is modelled by a magnetic dipole located under the photosphere. This simplified description allows us to study the spatial influence of an active region in the solar atmosphere in a rough but easy way. We find that the area of influence of the magnetic field of an active region on the solar atmosphere increases with both the maximum strength of the magnetic field in the active region and the depth of the dipole under the photosphere. For a typical active region, the magnetic field can be neglected for distances beyond ca. 700 Mm on the photosphere and two solar radii in the solar corona.
{"title":"Spatial Extent of the Magnetic Influence of an Active Region on the Solar Atmosphere","authors":"Gottfried Mann, Frédéric Schuller","doi":"10.1002/asna.70040","DOIUrl":"https://doi.org/10.1002/asna.70040","url":null,"abstract":"<div>\u0000 \u0000 <p>Solar activity can be witnessed in the form of sunspots and active regions, where the magnetic field is enhanced by up to a factor of 1000 as compared to that of the quiet Sun. In addition, solar activity manifests itself in terms of flares, jets, coronal mass ejections and the production of highly energetic particles. All these processes are governed by the solar magnetic field. Here we study the spatial reach of the influence of the magnetic field of active regions on the photosphere and in the solar corona. An active region is modelled by a magnetic dipole located under the photosphere. This simplified description allows us to study the spatial influence of an active region in the solar atmosphere in a rough but easy way. We find that the area of influence of the magnetic field of an active region on the solar atmosphere increases with both the maximum strength of the magnetic field in the active region and the depth of the dipole under the photosphere. For a typical active region, the magnetic field can be neglected for distances beyond ca. 700 Mm on the photosphere and two solar radii in the solar corona.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 9","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145476436","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}
Peter O. Hess, César A. Zen Vasconcellos, José de Freitas Pacheco, Fridolin Weber, Remo Ruffini, Dimiter Hadjimichef, Moisés Razeira, Benno Bodmann, Marcelo Netz-Marzola, Geovane Naysinger, Rodrigo Fraga da Silva, João G. G. Gimenez
We explore a noncommutative extension of branch-cut quantum gravity (BCQG), with a focus on its implications for early-universe inflation. Our framework builds on a three-field mini-superspace model involving a complex-valued cosmic-scale factor, a perfect-fluid field, and an inflaton-type scalar field. Using a Faddeev–Jackiw symplectic deformation of the conventional Poisson algebra, we construct a noncommutative phase space and derive a modified Wheeler–DeWitt equation. Analytic solutions to the wave function of the universe are obtained and analyzed. We show that noncommutativity induces coupling between ultraviolet and infrared modes, naturally leading to an inflationary phase without requiring fine-tuned initial conditions. This feature offers a novel alternative to standard inflationary models. We also discuss how the structure of the wave function in this framework may relate to primordial density perturbations. While some aspects of this theory remain speculative, the mathematical formulation provides a consistent path toward integrating quantum gravitational effects into early cosmological dynamics.
{"title":"Cosmic Inflation in an Extended Noncommutative Foliated Quantum Gravity: The Wave Function of the Universe","authors":"Peter O. Hess, César A. Zen Vasconcellos, José de Freitas Pacheco, Fridolin Weber, Remo Ruffini, Dimiter Hadjimichef, Moisés Razeira, Benno Bodmann, Marcelo Netz-Marzola, Geovane Naysinger, Rodrigo Fraga da Silva, João G. G. Gimenez","doi":"10.1002/asna.70039","DOIUrl":"https://doi.org/10.1002/asna.70039","url":null,"abstract":"<div>\u0000 \u0000 <p>We explore a noncommutative extension of branch-cut quantum gravity (BCQG), with a focus on its implications for early-universe inflation. Our framework builds on a three-field mini-superspace model involving a complex-valued cosmic-scale factor, a perfect-fluid field, and an inflaton-type scalar field. Using a Faddeev–Jackiw symplectic deformation of the conventional Poisson algebra, we construct a noncommutative phase space and derive a modified Wheeler–DeWitt equation. Analytic solutions to the wave function of the universe are obtained and analyzed. We show that noncommutativity induces coupling between ultraviolet and infrared modes, naturally leading to an inflationary phase without requiring fine-tuned initial conditions. This feature offers a novel alternative to standard inflationary models. We also discuss how the structure of the wave function in this framework may relate to primordial density perturbations. While some aspects of this theory remain speculative, the mathematical formulation provides a consistent path toward integrating quantum gravitational effects into early cosmological dynamics.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 7-8","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135441","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}
Magdy R. Sanad, Yasser H. M. Hendy, Helal I. Abdel Rahman, Doaa Eid
We present Gaia DR3 data and estimated the cluster radius, color-magnitude diagram and the membership probability of the open cluster NGC 7209 using the machine learning algorithm pyUPMASK. We evaluated the membership probability of the RS CVn eclipsing binary system AR Lac. We reported International Ultraviolet Explorer (IUE) observations during the period (1979–1994) of the RS CVn eclipsing binary system AR Lac to describe the spectral behavior and the physical conditions in its atmosphere. The observations reveal indications of flare activity in the transition region. Besides the flaring activity, the emission lines show a range of variations between high, intermediate, and low flux values. The relation between line fluxes and orbital phases is found. The flaring activity is found in 1979, 1990, and 1994. The reddening of AR Lac was estimated from the 2200 Å absorption feature to be . The average mass loss rate is found to be , the average temperature of the emitting region is determined by using Planck's equation to be , the energy of
{"title":"Spectral Variations, Quiet Chromosphere and Flaring of Transition Region of AR Lac in UV and Gaia DR3 in the Field Open Cluster NGC 7209","authors":"Magdy R. Sanad, Yasser H. M. Hendy, Helal I. Abdel Rahman, Doaa Eid","doi":"10.1002/asna.70037","DOIUrl":"https://doi.org/10.1002/asna.70037","url":null,"abstract":"<div>\u0000 \u0000 <p>We present Gaia DR3 data and estimated the cluster radius, color-magnitude diagram and the membership probability of the open cluster NGC 7209 using the machine learning algorithm pyUPMASK. We evaluated the membership probability of the RS CVn eclipsing binary system AR Lac. We reported International Ultraviolet Explorer (IUE) observations during the period (1979–1994) of the RS CVn eclipsing binary system AR Lac to describe the spectral behavior and the physical conditions in its atmosphere. The observations reveal indications of flare activity in the transition region. Besides the flaring activity, the emission lines show a range of variations between high, intermediate, and low flux values. The relation between line fluxes and orbital phases is found. The flaring activity is found in 1979, 1990, and 1994. The reddening of AR Lac was estimated from the 2200 Å absorption feature to be <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>E</mi>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mrow>\u0000 <mi>B</mi>\u0000 <mo>−</mo>\u0000 <mi>V</mi>\u0000 </mrow>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <mo>=</mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation>$$ Eleft(B-Vright)=0 $$</annotation>\u0000 </semantics></math>. The average mass loss rate is found to be <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≈</mo>\u0000 <mn>3.2</mn>\u0000 <mo>×</mo>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>9</mn>\u0000 </mrow>\u0000 </msup>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mo>⊙</mo>\u0000 </msub>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mtext>year</mtext>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ approx 3.2times {10}^{-9}{M}_{odot}kern0.1em {mathrm{year}}^{-1} $$</annotation>\u0000 </semantics></math>, the average temperature of the emitting region is determined by using Planck's equation to be <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≈</mo>\u0000 <mn>9.2</mn>\u0000 <mo>×</mo>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mn>4</mn>\u0000 </msup>\u0000 <mspace></mspace>\u0000 <mi>K</mi>\u0000 </mrow>\u0000 <annotation>$$ approx 9.2times {10}^4;mathrm{K} $$</annotation>\u0000 </semantics></math>, the energy of","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 6","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843373","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}
Neutron stars, particularly magnetars, exhibit extreme physical conditions with some of the strongest magnetic fields in the universe. Understanding the evolution of these magnetic fields is crucial for interpreting their observed properties, such as high braking indices and X-ray emissions. In this work, we investigate the decay of multipole magnetic fields in neutron stars by incorporating general relativistic (GR) effects into the induction equations. We derive GR-corrected evolution equations for dipole (), quadrupole (), and octupole () fields, considering both toroidal and poloidal components. Our calculations show that GR effects significantly extend the magnetic field decay timescales, with the redshift factor for a typical neutron star. We find that the GR-corrected decay timescales better align with observed characteristics of magnetars. Additionally, we discuss the implications of our model for X-ray emissions and magnetic energy release rates in magnetars. Our results highlight the importance of GR corrections for accurate predictions of magnetic field evolution and related observational phenomena.
{"title":"General Relativistic Effects on Multipole Magnetic Field Evolution in Neutron Stars: Implications for High-Braking-Index Magnetars","authors":"Zhifu Gao, Sheng-Nan Sun, Wen-Qi Ma, Hao Shan","doi":"10.1002/asna.70032","DOIUrl":"https://doi.org/10.1002/asna.70032","url":null,"abstract":"<div>\u0000 \u0000 <p>Neutron stars, particularly magnetars, exhibit extreme physical conditions with some of the strongest magnetic fields in the universe. Understanding the evolution of these magnetic fields is crucial for interpreting their observed properties, such as high braking indices and X-ray emissions. In this work, we investigate the decay of multipole magnetic fields in neutron stars by incorporating general relativistic (GR) effects into the induction equations. We derive GR-corrected evolution equations for dipole (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>l</mi>\u0000 <mo>=</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 <annotation>$$ l=1 $$</annotation>\u0000 </semantics></math>), quadrupole (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>l</mi>\u0000 <mo>=</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 <annotation>$$ l=2 $$</annotation>\u0000 </semantics></math>), and octupole (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>l</mi>\u0000 <mo>=</mo>\u0000 <mn>3</mn>\u0000 </mrow>\u0000 <annotation>$$ l=3 $$</annotation>\u0000 </semantics></math>) fields, considering both toroidal and poloidal components. Our calculations show that GR effects significantly extend the magnetic field decay timescales, with the redshift factor <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>z</mi>\u0000 <mo>≈</mo>\u0000 <mn>0.23</mn>\u0000 </mrow>\u0000 <annotation>$$ zapprox 0.23 $$</annotation>\u0000 </semantics></math> for a typical neutron star. We find that the GR-corrected decay timescales better align with observed characteristics of magnetars. Additionally, we discuss the implications of our model for X-ray emissions and magnetic energy release rates in magnetars. Our results highlight the importance of GR corrections for accurate predictions of magnetic field evolution and related observational phenomena.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 7-8","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135422","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}
C. A. Galante, G. E. Romero, J. Saponara, P. Benaglia
NGC 4527 is a nearby edge-on spiral galaxy with both starburst and AGN features, hosting a LINER nucleus. We present a radio study of the large-scale structure and nuclear region of this galaxy, based on new uGMRT observations at 700 and 1230 MHz. Our continuum maps reveal extended emission tracing the stellar disk, with no evidence of a radio halo. The spectral index distribution and the presence of PAHs across the disk are consistent with ongoing star formation. In the nuclear region we resolve three compact sources: one at the galactic centre and two symmetrically aligned with the major axis at pc. The spectral index values and the destruction of PAHs in the central source, together with previously detected X-rays emission, suggest the presence of a low-luminosity AGN. The two off-centre sources are consistent with a star formation ring, coincident with a molecular gas ring previously reported. We explore a scenario where super-Eddington accretion onto the black hole drives a dense wind that falls back onto the disk, triggering star formation in a circumnuclear ring.
NGC 4527是一个边缘上的螺旋星系，同时具有星暴和AGN的特征，拥有一个LINER核。我们在700和1230 MHz的新uGMRT观测基础上，对这个星系的大尺度结构和核区进行了无线电研究。我们的连续图显示了延伸的辐射追踪恒星盘，没有射电晕的证据。光谱指数分布和多环芳烃的存在与正在进行的恒星形成一致。在核区，我们解析了三个致密源：一个在银河系中心，两个在～ 400 $$ sim 400 $$ pc处与长轴对称排列。光谱指数值和中心源中多环芳烃的破坏，以及先前检测到的x射线发射，表明存在低亮度AGN。这两个偏离中心的源与恒星形成环一致，与先前报道的分子气体环一致。我们探索了一种场景，即黑洞的超级爱丁顿吸积驱动稠密的风落回圆盘上，引发环核环中的恒星形成。
{"title":"High Resolution Radio Analysis of the Starburst Galaxy NGC 4527: Signatures of an AGN Core","authors":"C. A. Galante, G. E. Romero, J. Saponara, P. Benaglia","doi":"10.1002/asna.70036","DOIUrl":"https://doi.org/10.1002/asna.70036","url":null,"abstract":"<div>\u0000 \u0000 <p>NGC 4527 is a nearby edge-on spiral galaxy with both starburst and AGN features, hosting a LINER nucleus. We present a radio study of the large-scale structure and nuclear region of this galaxy, based on new uGMRT observations at 700 and 1230 MHz. Our continuum maps reveal extended emission tracing the stellar disk, with no evidence of a radio halo. The spectral index distribution and the presence of PAHs across the disk are consistent with ongoing star formation. In the nuclear region we resolve three compact sources: one at the galactic centre and two symmetrically aligned with the major axis at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>400</mn>\u0000 </mrow>\u0000 <annotation>$$ sim 400 $$</annotation>\u0000 </semantics></math> pc. The spectral index values and the destruction of PAHs in the central source, together with previously detected X-rays emission, suggest the presence of a low-luminosity AGN. The two off-centre sources are consistent with a star formation ring, coincident with a molecular gas ring previously reported. We explore a scenario where super-Eddington accretion onto the black hole drives a dense wind that falls back onto the disk, triggering star formation in a circumnuclear ring.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 9","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145476381","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}
M. Scardia, J.-L. Prieur, J.-P. Rivet, D. Vernet, E. Aristidi, J. F. Ling, L. Piccotti, L. Pansecchi, R. W. Argyle, L. Abe, P. Bendjoya, L. Maccarini
We present relative astrometric measurements of visual double stars, made in 2017–2018 with the speckle camera PISCO at the 1-m Epsilon telescope of the C2PU facility (Observatoire de la Côte d'Azur, Calern site). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. From our observations of 1400 multiple stars, we obtained 1376 new measurements with angular separations in the range —, and an average accuracy of . The mean error on the position angles is 0°.50. Most of the position angles were determined without the usual 180° ambiguity with the application of the direct vector auto-correlation technique and/or by inspection of the long integration files. We present new and revised orbits for A1913 AB, A1710, COU1394, BU1185, A122, A570, HU577, COU812, HU332, A2095 AB, and A884, partly derived from our PISCO observations. The corresponding estimated values for the masses of those systems are compatible with the spectral types.
{"title":"Speckle Observations With PISCO in Calern (France): II. Astrometric Measurements of Visual Double Stars in 2017–2018 and New or Revised Orbits for A1913 AB, A1710, COU1394, BU1185, A122, A570, HU577, COU812, HU332, A2095 AB, and A884","authors":"M. Scardia, J.-L. Prieur, J.-P. Rivet, D. Vernet, E. Aristidi, J. F. Ling, L. Piccotti, L. Pansecchi, R. W. Argyle, L. Abe, P. Bendjoya, L. Maccarini","doi":"10.1002/asna.70000","DOIUrl":"https://doi.org/10.1002/asna.70000","url":null,"abstract":"<p>We present relative astrometric measurements of visual double stars, made in 2017–2018 with the speckle camera PISCO at the 1-m Epsilon telescope of the C2PU facility (Observatoire de la Côte d'Azur, Calern site). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. From our observations of 1400 multiple stars, we obtained 1376 new measurements with angular separations in the range <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mo>″</mo>\u0000 </msup>\u0000 <mn>.1</mn>\u0000 </mrow>\u0000 <annotation>$$ {0}^{{primeprime} }.1 $$</annotation>\u0000 </semantics></math>—<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mn>8</mn>\u0000 <mo>″</mo>\u0000 </msup>\u0000 <mn>.5</mn>\u0000 </mrow>\u0000 <annotation>$$ {8}^{{primeprime} }.5 $$</annotation>\u0000 </semantics></math>, and an average accuracy of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mo>″</mo>\u0000 </msup>\u0000 <mn>.008</mn>\u0000 </mrow>\u0000 <annotation>$$ {0}^{{primeprime} }.008 $$</annotation>\u0000 </semantics></math>. The mean error on the position angles is 0°.50. Most of the position angles were determined without the usual 180° ambiguity with the application of the direct vector auto-correlation technique and/or by inspection of the long integration files. We present new and revised orbits for A1913 AB, A1710, COU1394, BU1185, A122, A570, HU577, COU812, HU332, A2095 AB, and A884, partly derived from our PISCO observations. The corresponding estimated values for the masses of those systems are compatible with the spectral types.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 6","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.70000","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843432","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号