New Astronomy最新文献_第4页

Light curve models of convective common envelopes 对流普通包层的光曲线模型

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-09-27 DOI: 10.1016/j.newast.2025.102477

N. Noughani , J. Nordhaus , M. Richmond , E.C. Wilson

Common envelopes are thought to be the main method for producing tight binaries in the universe as the orbital period shrinks by several orders of magnitude during this phase. Despite their importance for various evolutionary channels, direct detections are rare, and thus observational constraints on common envelope physics are often inferred from post-CE populations. Population constraints suggest that the CE phase must be highly inefficient at using orbital energy to drive envelope ejection for low-mass systems and highly efficient for high-mass systems. Such a dichotomy has been explained by an interplay between convection, radiation and orbital decay. If convective transport to the surface occurs faster than the orbit decays, the CE self-regulates and radiatively cools. Once the orbit shrinks such that convective transport is slow compared to orbital decay, a burst occurs as the release of orbital energy can be far in excess of that required to unbind the envelope. With the anticipation of first light for the Rubin Observatory, we calculate light curve models for convective common envelopes and provide the time evolution of apparent magnitudes for the Rubin filters. Convection imparts a distinct signature in the light curves and lengthens the timescales during which they are observable. Given Rubin limiting magnitudes, convective CEs should be detectable out to distances of

\sim

8 Mpc at a rate of

\sim

0.1 day⁻¹ and provide an intriguing observational test of common envelope physics.

普通的包层被认为是宇宙中产生紧密双星的主要方法，因为轨道周期在这个阶段会缩小几个数量级。尽管它们对各种进化渠道很重要，但直接探测很少，因此对共同包络物理的观测约束通常是从ce后种群中推断出来的。人口约束表明，CE阶段在使用轨道能量驱动包络抛射时，对于低质量系统必须是非常低效的，而对于高质量系统则是非常高效的。这种二分法可以用对流、辐射和轨道衰变之间的相互作用来解释。如果到表面的对流传输比轨道衰减的速度快，CE就会自我调节并进行辐射冷却。一旦轨道收缩到对流传输比轨道衰减慢的程度，就会发生爆发，因为轨道释放的能量可能远远超过解开包络层所需的能量。根据鲁宾天文台第一束光的预期，我们计算了对流共包络的光曲线模型，并提供了鲁宾滤光器视星等的时间演化。对流在光曲线中赋予了一个明显的特征，并延长了它们可观测的时间尺度。考虑到鲁宾极限等，对流ce应该在~ 8 Mpc的距离内以~ 0.1天−1的速率被探测到，并为普通包膜物理提供了一个有趣的观测测试。

{"title":"Light curve models of convective common envelopes","authors":"N. Noughani , J. Nordhaus , M. Richmond , E.C. Wilson","doi":"10.1016/j.newast.2025.102477","DOIUrl":"10.1016/j.newast.2025.102477","url":null,"abstract":"<div><div>Common envelopes are thought to be the main method for producing tight binaries in the universe as the orbital period shrinks by several orders of magnitude during this phase. Despite their importance for various evolutionary channels, direct detections are rare, and thus observational constraints on common envelope physics are often inferred from post-CE populations. Population constraints suggest that the CE phase must be highly inefficient at using orbital energy to drive envelope ejection for low-mass systems and highly efficient for high-mass systems. Such a dichotomy has been explained by an interplay between convection, radiation and orbital decay. If convective transport to the surface occurs faster than the orbit decays, the CE self-regulates and radiatively cools. Once the orbit shrinks such that convective transport is slow compared to orbital decay, a burst occurs as the release of orbital energy can be far in excess of that required to unbind the envelope. With the anticipation of first light for the Rubin Observatory, we calculate light curve models for convective common envelopes and provide the time evolution of apparent magnitudes for the Rubin filters. Convection imparts a distinct signature in the light curves and lengthens the timescales during which they are observable. Given Rubin limiting magnitudes, convective CEs should be detectable out to distances of <span><math><mo>∼</mo></math></span> 8 Mpc at a rate of <span><math><mo>∼</mo></math></span> 0.1 day<sup>−1</sup> and provide an intriguing observational test of common envelope physics.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"122 ","pages":"Article 102477"},"PeriodicalIF":2.1,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145332742","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}

引用次数: 0

Numerical study of relativistic jet propagation inside uniform interstellar medium issuing from an Active Galactic Nuclei 活动星系核发出的均匀星际介质内相对论射流传播的数值研究

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-09-20 DOI: 10.1016/j.newast.2025.102467

Ribhu Pal, Arnab Roy

A direct numerical simulation (DNS) of two-dimensional axisymmetric relativistic jet propagation through a uniform interstellar medium was carried out by solving the relativistic magnetohydrodynamic (RMHD) equations with the PLUTO solver (Mignone et al., 2007). Moreover, a comprehensive discussion of the detailed flow features involved in this propagation is provided throughout this study. The physics underlying shock-vorticity interaction during relativistic jet propagation through a uniform interstellar medium has been thoroughly described in this present study. Additionally, the probability density distribution (p.d.f) of enstrophy (

ϵ

) indicates that the highest intensity of fluid rotation, and consequently turbulence, is manifested within the cocoon instead of the frontal region of the relativistic jet.

利用PLUTO求解器（Mignone et al., 2007）求解相对论磁流体动力学（RMHD）方程，对二维轴对称相对论射流在均匀星际介质中的传播进行了直接数值模拟（DNS）。此外，在整个研究中，还提供了有关这种传播的详细流动特征的全面讨论。本文对相对论性射流在均匀星际介质中传播过程中激波涡度相互作用的物理现象进行了全面的描述。此外，熵（御御）的概率密度分布（p.d.f）表明，最高强度的流体旋转和湍流出现在茧内，而不是在相对论性射流的锋面区域。

引用次数: 0

Effects of ion source term on the sheath in electronegative dusty plasmas 离子源项对电负性尘埃等离子体鞘层的影响

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-09-16 DOI: 10.1016/j.newast.2025.102476

S.A. Galyanseyedi , G. Foroutan , T. Mohsenpour

This study examines a stationary model of the magneto-electronegative dusty plasma sheath, treating dust particles as a cold fluid. In the present model, the electron and negative ion are in Maxwellian thermodynamic equilibrium, while positive ions are considered as a hot fluid with an ion source term. The effects of ion sources and ionization frequencies (IFs) on the sheath are examined to compare their contributions. A modified sheath criterion and floating potential are established theoretically using the Sagdeev potential method. The governing equations of the model are then solved numerically. The effects of the ion source on sheath electric potential, particle density, positive ion velocity, and space charge density are also investigated. It was found that the modified Bohm criterion decreases with an increase of the IF. It can be seen that the different ion source term is effective in the dusty plasma sheath structure.

本研究考察了磁电负性尘埃等离子体鞘的固定模型，将尘埃颗粒视为冷流体。在该模型中，电子和负离子处于麦克斯韦热力学平衡，而正离子被认为是具有离子源项的热流体。离子源和电离频率（if）对鞘的影响进行了检查，比较他们的贡献。利用Sagdeev势法，从理论上建立了改进的鞘层判据和浮动势。然后对模型的控制方程进行了数值求解。研究了离子源对鞘层电位、粒子密度、正离子速度和空间电荷密度的影响。结果表明，修正Bohm准则随IF的增大而减小。可见，不同离子源项在尘埃等离子体鞘层结构中是有效的。

引用次数: 0

High power accretion in massive binary systems and the impact of metallicity 大质量双星系统的高功率吸积和金属丰度的影响

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-09-11 DOI: 10.1016/j.newast.2025.102475

Bhawna Mukhija , Amit Kashi

During a giant eruption of a very massive star in the binary system, the companion star can accrete a large amount of mass that can change its properties and potentially its subsequent evolution. The effect depends on the companion mass, metallicity, the amount of mass it accreted, orbital parameters and other parameters. We simulate individual companion stars assuming they undergo such accretion events. We study the envelope properties of 20

M_{⊙}

and 30

M_{⊙}

single massive stars at different metallicities (

Z = 0.02

,

Z = 0.008

and

Z = 0.004

) during accretion at different rates, from

1 0^{- 5}

to

1 0^{- 2} M_{⊙} {yr}^{- 1}

. For the lower accretion rates we simulate, the stars remains hot, while at higher accretion rates, it becomes cooler and inflates. This behavior is observed in both stars but occurs at different accretion rates. Higher metallicity stars exhibit greater variations in accretion luminosity for the same accretion rate and stellar mass compared to lower metallicity stars. While higher metallicity stars typically have larger stellar envelopes, suggesting smaller variations in luminosity at Galactic metallicity compared to the LMC and SMC, our results show the opposite.

在双星系统中，一颗质量非常大的恒星爆发时，伴星可以吸积大量的质量，这可能会改变它的性质，并可能改变它随后的演化。这种效应取决于伴星的质量、金属丰度、它所吸积的质量、轨道参数和其他参数。我们模拟单个伴星，假设它们经历了这样的吸积事件。我们研究了不同金属丰度（Z=0.02， Z=0.008和Z=0.004）的20 M⊙和30 M⊙单质量恒星在不同吸积速率（从10−5到10−2M⊙yr−1）下的包层性质。对于我们模拟的较低吸积率，恒星保持热，而在较高的吸积率下，它变得更冷并膨胀。这种行为在两颗恒星中都可以观察到，但发生在不同的吸积速率下。与金属丰度较低的恒星相比，在相同的吸积速率和恒星质量下，金属丰度较高的恒星在吸积光度上表现出更大的变化。虽然金属丰度较高的恒星通常有更大的恒星包层，这表明与LMC和SMC相比，银河系金属丰度的光度变化较小，但我们的结果恰恰相反。

{"title":"High power accretion in massive binary systems and the impact of metallicity","authors":"Bhawna Mukhija , Amit Kashi","doi":"10.1016/j.newast.2025.102475","DOIUrl":"10.1016/j.newast.2025.102475","url":null,"abstract":"<div><div>During a giant eruption of a very massive star in the binary system, the companion star can accrete a large amount of mass that can change its properties and potentially its subsequent evolution. The effect depends on the companion mass, metallicity, the amount of mass it accreted, orbital parameters and other parameters. We simulate individual companion stars assuming they undergo such accretion events. We study the envelope properties of 20 <span><math><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></math></span> and 30 <span><math><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></math></span> single massive stars at different metallicities (<span><math><mrow><mi>Z</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>02</mn></mrow></math></span>, <span><math><mrow><mi>Z</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>008</mn></mrow></math></span> and <span><math><mrow><mi>Z</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>004</mn></mrow></math></span>) during accretion at different rates, from <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span> to <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mspace></mspace><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub><mspace></mspace><msup><mrow><mi>yr</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. For the lower accretion rates we simulate, the stars remains hot, while at higher accretion rates, it becomes cooler and inflates. This behavior is observed in both stars but occurs at different accretion rates. Higher metallicity stars exhibit greater variations in accretion luminosity for the same accretion rate and stellar mass compared to lower metallicity stars. While higher metallicity stars typically have larger stellar envelopes, suggesting smaller variations in luminosity at Galactic metallicity compared to the LMC and SMC, our results show the opposite.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"122 ","pages":"Article 102475"},"PeriodicalIF":2.1,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049122","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}

引用次数: 0

Solar energetic particle transport via the heliospheric current sheet: Evidence of a ground-level response on All Saints Day, 2014 太阳高能粒子通过日球层电流片传输：2014年万圣节地面响应的证据

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-09-02 DOI: 10.1016/j.newast.2025.102468

Marcel Nogueira de Oliveira , Carlos E. Navia , Andre Asevedo Nepomuceno

We investigate the physical mechanisms responsible for the solar energetic particle (SEP) event observed on 1 November 2014, during which several ground-based detectors in both hemispheres, specifically those located on the sunlit western side of Earth, recorded simultaneous enhancements in counting rates. The event is attributed to Active Region (AR) 2192, one of the most active sunspot groups of Solar Cycle 24, which at the time was situated near the western limb of the solar disk, approaching the far side of the Sun. A plausible scenario involves a combination of solar eruptive activity, particle acceleration by a shock wave driven by a coronal mass ejection (CME), and the presence of a heliospheric current sheet (HCS) sector crossing, which may have enhanced magnetic connectivity between the Sun and Earth. We emphasize data from the New-Tupi muon detector, operating in scaler mode and located near the central region of the South Atlantic Anomaly (SAA). The particle excess detected on 1 November 2014 by ground-based instruments spanning different rigidity regimes, in conjunction with satellite observations, indicates that the signal was not a localized phenomenon. Assuming a power-law energy spectrum for the SEP population, we find that its high-energy tail in the GeV range is consistent with proton flux measurements reported by GOES-13. We present and discuss the details of these observations.

我们研究了2014年11月1日观测到的太阳高能粒子（SEP）事件的物理机制，在此期间，两个半球的几个地面探测器，特别是位于地球阳光照射的西侧的探测器，记录了计数率的同时增强。这一事件归因于活跃区（AR） 2192，这是太阳周期24中最活跃的太阳黑子群之一，当时位于太阳圆盘的西翼附近，接近太阳的远端。一种可能的情况包括太阳爆发活动、日冕物质抛射（CME）驱动的冲击波导致粒子加速，以及日球层电流片（HCS）扇区交叉的存在，这可能增强了太阳和地球之间的磁连性。我们强调来自New-Tupi介子探测器的数据，该探测器位于南大西洋异常（SAA）的中心区域附近，工作在标量模式。2014年11月1日，跨越不同刚性体系的地面仪器结合卫星观测检测到粒子过剩，表明该信号并非局域现象。假设SEP粒子群的能量谱为幂律，我们发现它在GeV范围内的高能尾巴与GOES-13报告的质子通量测量结果一致。我们提出并讨论这些观察的细节。

{"title":"Solar energetic particle transport via the heliospheric current sheet: Evidence of a ground-level response on All Saints Day, 2014","authors":"Marcel Nogueira de Oliveira , Carlos E. Navia , Andre Asevedo Nepomuceno","doi":"10.1016/j.newast.2025.102468","DOIUrl":"10.1016/j.newast.2025.102468","url":null,"abstract":"<div><div>We investigate the physical mechanisms responsible for the solar energetic particle (SEP) event observed on 1 November 2014, during which several ground-based detectors in both hemispheres, specifically those located on the sunlit western side of Earth, recorded simultaneous enhancements in counting rates. The event is attributed to Active Region (AR) 2192, one of the most active sunspot groups of Solar Cycle 24, which at the time was situated near the western limb of the solar disk, approaching the far side of the Sun. A plausible scenario involves a combination of solar eruptive activity, particle acceleration by a shock wave driven by a coronal mass ejection (CME), and the presence of a heliospheric current sheet (HCS) sector crossing, which may have enhanced magnetic connectivity between the Sun and Earth. We emphasize data from the New-Tupi muon detector, operating in scaler mode and located near the central region of the South Atlantic Anomaly (SAA). The particle excess detected on 1 November 2014 by ground-based instruments spanning different rigidity regimes, in conjunction with satellite observations, indicates that the signal was not a localized phenomenon. Assuming a power-law energy spectrum for the SEP population, we find that its high-energy tail in the GeV range is consistent with proton flux measurements reported by GOES-13. We present and discuss the details of these observations.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"122 ","pages":"Article 102468"},"PeriodicalIF":2.1,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934278","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}

引用次数: 0

Dataset of artefacts for machine learning applications in astronomy 天文学中机器学习应用的人工制品数据集

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-08-29 DOI: 10.1016/j.newast.2025.102466

Sreevarsha Sreejith , Maria V. Pruzhinskaya , Alina A. Volnova , Vadim V. Krushinsky , Konstantin L. Malanchev , Emille E.O. Ishida , Anastasia D. Lavrukhina , Timofey A. Semenikhin , Emmanuel Gangler , Matwey V. Kornilov , Vladimir S. Korolev

Accurate photometry in astronomical surveys is challenged by image artefacts, which affect measurements and degrade data quality. Due to the large amount of available data, this task is increasingly handled using machine learning algorithms, which often require a labelled training set to learn data patterns. We present an expert-labelled dataset of 1127 artefacts with 1213 labels from 26 fields in ZTF DR3, along with a complementary set of nominal objects. The artefact dataset was compiled using the active anomaly detection algorithm PineForest, developed by the SNAD team. These datasets can serve as valuable resources for real-bogus classification, catalogue cleaning, anomaly detection, and educational purposes. Both artefacts and nominal images are provided in FITS format in two sizes (28 × 28 and 63 × 63 pixels). The datasets are publicly available for further scientific applications.

在天文调查中，精确的光度测量受到图像伪影的挑战，这些伪影会影响测量结果并降低数据质量。由于大量的可用数据，这项任务越来越多地使用机器学习算法来处理，这通常需要一个标记的训练集来学习数据模式。我们提出了一个专家标记的数据集，包含来自ZTF DR3中26个领域的1127个人工制品和1213个标签，以及一组补充的标称对象。人工数据集使用SNAD团队开发的主动异常检测算法pinefforest进行编译。这些数据集可以作为真假分类、目录清理、异常检测和教育目的的宝贵资源。人工制品和标称图像都以FITS格式提供，有两种尺寸（28 × 28和63 × 63像素）。这些数据集是公开的，可用于进一步的科学应用。

{"title":"Dataset of artefacts for machine learning applications in astronomy","authors":"Sreevarsha Sreejith , Maria V. Pruzhinskaya , Alina A. Volnova , Vadim V. Krushinsky , Konstantin L. Malanchev , Emille E.O. Ishida , Anastasia D. Lavrukhina , Timofey A. Semenikhin , Emmanuel Gangler , Matwey V. Kornilov , Vladimir S. Korolev","doi":"10.1016/j.newast.2025.102466","DOIUrl":"10.1016/j.newast.2025.102466","url":null,"abstract":"<div><div>Accurate photometry in astronomical surveys is challenged by image artefacts, which affect measurements and degrade data quality. Due to the large amount of available data, this task is increasingly handled using machine learning algorithms, which often require a labelled training set to learn data patterns. We present an expert-labelled dataset of 1127 artefacts with 1213 labels from 26 fields in ZTF DR3, along with a complementary set of nominal objects. The artefact dataset was compiled using the active anomaly detection algorithm <span>PineForest</span>, developed by the SNAD team. These datasets can serve as valuable resources for real-bogus classification, catalogue cleaning, anomaly detection, and educational purposes. Both artefacts and nominal images are provided in FITS format in two sizes (28 × 28 and 63 × 63 pixels). The datasets are publicly available for further scientific applications.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"122 ","pages":"Article 102466"},"PeriodicalIF":2.1,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020441","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}

引用次数: 0

First detection of ethylene oxide and acetaldehyde in hot core G358.93–0.03 MM1: Tracing prebiotic oxygen chemistry 热芯G358.93-0.03 MM1中环氧乙烷和乙醛的首次检测：示踪益生元氧化学

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-08-25 DOI: 10.1016/j.newast.2025.102465

Arijit Manna, Sabyasachi Pal

Ethylene oxide (c-

) and its isomer, acetaldehyde (CH₃CHO), are important complex organic molecules owing to their potential role in the formation of amino acids (R–CH(NH₂)-COOH) in interstellar medium. The detection of c-

in hot molecular cores suggests the possible existence of larger ring-shaped molecules containing more than three carbon atoms, such as furan (c-

), which shares structural similarities with ribose (C₅H₁₀O₅), the sugar component of DNA. In this study, we report the first detection of the rotational emission lines of c-

and CH₃CHO towards the hot molecular core G358.93–0.03 MM1, based on observations from the Atacama Large Millimeter/Submillimeter Array (ALMA) in band 7. The fractional abundances of c-

and CH₃CHO relative to H₂ are

(2.1 \pm 0.2) \times 1 0^{- 9}

and

(7.1 \pm 0.9) \times 1 0^{- 9}

, respectively. The column density ratio between CH₃CHO and c-

is

3.4 \pm 0.7

. A Pearson correlation heat map reveals strong positive correlations (

r

>

0.5) between the abundances and excitation temperatures of c-

and CH₃CHO, suggesting a possible chemical connection between those two molecules. To investigate this further, we conducted a two-phase warm-up chemical model using the gas-grain chemical code UCLCHEM. A comparison between our derived abundances and the predictions from our chemical model and existence model demonstrates good agreement within factors of 0.73 and 0.74, respectively. We propose that c-

may form in G358.93–0.03 MM1 via the grain surface reaction between C₂H₄ and O, but CH₃CHO may be produced through the surface reaction between CH₃ and HCO.

环氧乙烷（c-）及其异构体乙醛（CH3CHO）是重要的复杂有机分子，因为它们在星际介质中形成氨基酸（R-CH (NH2)- cooh）的潜在作用。在热分子核中检测到c-表明可能存在含有三个以上碳原子的更大的环状分子，如呋喃（c-），它与DNA的糖成分核糖（C5H10O5）具有结构相似性。在这项研究中，我们报道了基于阿塔卡马大型毫米/亚毫米阵列（ALMA）在波段7的观测，首次探测到c-和CH3CHO对热分子核心G358.93-0.03 MM1的旋转发射线。c-和CH3CHO相对于H2的丰度分别为（2.1±0.2）×10−9和（7.1±0.9）×10−9。CH3CHO与c-的柱密度比为3.4±0.7。Pearson相关热图显示，c-和CH3CHO的丰度和激发温度之间存在强正相关（r > 0.5），这表明这两个分子之间可能存在化学联系。为了进一步研究这一点，我们使用气粒化学代码UCLCHEM进行了两相预热化学模型。我们的推导丰度与我们的化学模型和存在模型的预测之间的比较表明，在分别为0.73和0.74的因子范围内，我们的丰度得到了很好的一致性。我们提出在G358.93-0.03 MM1中，c-可能是通过C2H4和O之间的晶粒表面反应生成的，而CH3CHO可能是通过CH3和HCO之间的表面反应生成的。

{"title":"First detection of ethylene oxide and acetaldehyde in hot core G358.93–0.03 MM1: Tracing prebiotic oxygen chemistry","authors":"Arijit Manna, Sabyasachi Pal","doi":"10.1016/j.newast.2025.102465","DOIUrl":"10.1016/j.newast.2025.102465","url":null,"abstract":"<div><div>Ethylene oxide (c- <figure><img></figure> ) and its isomer, acetaldehyde (CH<sub>3</sub>CHO), are important complex organic molecules owing to their potential role in the formation of amino acids (R–CH(NH<sub>2</sub>)-COOH) in interstellar medium. The detection of c- <figure><img></figure> in hot molecular cores suggests the possible existence of larger ring-shaped molecules containing more than three carbon atoms, such as furan (c- <figure><img></figure> ), which shares structural similarities with ribose (C<sub>5</sub>H<sub>10</sub>O<sub>5</sub>), the sugar component of DNA. In this study, we report the first detection of the rotational emission lines of c- <figure><img></figure> and CH<sub>3</sub>CHO towards the hot molecular core G358.93–0.03 MM1, based on observations from the Atacama Large Millimeter/Submillimeter Array (ALMA) in band 7. The fractional abundances of c- <figure><img></figure> and CH<sub>3</sub>CHO relative to H<sub>2</sub> are <span><math><mrow><mrow><mo>(</mo><mn>2</mn><mo>.</mo><mn>1</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>2</mn><mo>)</mo></mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mrow><mo>(</mo><mn>7</mn><mo>.</mo><mn>1</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>9</mn><mo>)</mo></mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup></mrow></math></span>, respectively. The column density ratio between CH<sub>3</sub>CHO and c- <figure><img></figure> is <span><math><mrow><mn>3</mn><mo>.</mo><mn>4</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>7</mn></mrow></math></span>. A Pearson correlation heat map reveals strong positive correlations (<span><math><mi>r</mi></math></span> <span><math><mo>></mo></math></span> 0.5) between the abundances and excitation temperatures of c- <figure><img></figure> and CH<sub>3</sub>CHO, suggesting a possible chemical connection between those two molecules. To investigate this further, we conducted a two-phase warm-up chemical model using the gas-grain chemical code UCLCHEM. A comparison between our derived abundances and the predictions from our chemical model and existence model demonstrates good agreement within factors of 0.73 and 0.74, respectively. We propose that c- <figure><img></figure> may form in G358.93–0.03 MM1 via the grain surface reaction between C<sub>2</sub>H<sub>4</sub> and O, but CH<sub>3</sub>CHO may be produced through the surface reaction between CH<sub>3</sub> and HCO.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"122 ","pages":"Article 102465"},"PeriodicalIF":2.1,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934279","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}

引用次数: 0

Non-singular bounce scenario of Higher dimensional dark energy cosmological model in Lyra geometry 天琴座几何中高维暗能量宇宙模型的非奇异弹跳情形

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-08-20 DOI: 10.1016/j.newast.2025.102464

Kangujam Priyokumar Singh, Asem Jotin Meitei

In this work, we examine a five-dimensional anisotropic Bianchi type III cosmological model within the framework of Lyra geometry. We investigate the matter bounce scenario under the dark energy condition for the equation of state relationship

ρ = W p

with

W = - 1

. Utilizing the energy–momentum tensor of a perfect fluid, we derive the solution for the model universe. Our proposed model also evaluates the behavior of energy conditions, state-finders, the current value of the deceleration parameter and stability conditions.

在这项工作中，我们在天琴座几何的框架内研究了一个五维各向异性的Bianchi III型宇宙学模型。我们研究了在暗能量条件下，ρ=Wp， W= - 1的状态关系方程下的物质弹跳情形。利用完美流体的能量动量张量，我们推导出模型宇宙的解。我们提出的模型还评估了能量条件、状态检测器、减速参数的当前值和稳定性条件的行为。

引用次数: 0

Dark energy parametrizations in Einstein–Aether gravity with cubic curvature corrections 具有三次曲率修正的爱因斯坦-以太引力中的暗能量参数化

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-08-20 DOI: 10.1016/j.newast.2025.102462

Mithun Bairagi

We investigate the late-time cosmic acceleration within the framework of generalized Einstein-Aether gravity incorporating cubic curvature corrections. Employing three widely used dynamical dark energy parametrizations-CPL, JBP, and BA, we reconstruct the cosmic expansion history by constraining the free model parameters using Type Ia Supernova (SN Ia) data from the Pantheon compilations via a

χ^{2}

-minimization approach. We determine best-fit values for the model parameters and evaluate key cosmological quantities such as the dark energy density

Ω_{{de}_{0}}

,the matter density

Ω_{m_{0}}

, the Hubble constant

H_{0}

, and the deceleration parameter

q_{0}

of the present universe. We also examine the evolution of the potential

V (z)

and the kinetic energy

\frac{{\dot{ϕ}}^{2}}{2}

of the equivalent scalar field representing dark energy as functions of redshift

z

.

我们在包含三次曲率修正的广义爱因斯坦-以太引力框架内研究了晚时宇宙加速度。采用cpl、JBP和BA三种常用的动态暗能量参数化方法，利用来自Pantheon的Ia型超新星（SN Ia）数据，通过χ2最小化方法，通过约束自由模型参数重建宇宙膨胀历史。我们确定模型参数的最佳拟合值，并评估关键的宇宙学量，如暗能量密度Ωde0、物质密度Ωm0、哈勃常数H0和当前宇宙的减速参数q0。我们还研究了代表暗能量的等效标量场的势能V(z)和动能φ(22)作为红移z的函数的演变。

{"title":"Dark energy parametrizations in Einstein–Aether gravity with cubic curvature corrections","authors":"Mithun Bairagi","doi":"10.1016/j.newast.2025.102462","DOIUrl":"10.1016/j.newast.2025.102462","url":null,"abstract":"<div><div>We investigate the late-time cosmic acceleration within the framework of generalized Einstein-Aether gravity incorporating cubic curvature corrections. Employing three widely used dynamical dark energy parametrizations-CPL, JBP, and BA, we reconstruct the cosmic expansion history by constraining the free model parameters using Type Ia Supernova (SN Ia) data from the Pantheon compilations via a <span><math><msup><mrow><mi>χ</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>-minimization approach. We determine best-fit values for the model parameters and evaluate key cosmological quantities such as the dark energy density <span><math><msub><mrow><mi>Ω</mi></mrow><mrow><msub><mrow><mtext>de</mtext></mrow><mrow><mn>0</mn></mrow></msub></mrow></msub></math></span>,the matter density <span><math><msub><mrow><mi>Ω</mi></mrow><mrow><msub><mrow><mtext>m</mtext></mrow><mrow><mn>0</mn></mrow></msub></mrow></msub></math></span>, the Hubble constant <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, and the deceleration parameter <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> of the present universe. We also examine the evolution of the potential <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> and the kinetic energy <span><math><mfrac><mrow><msup><mrow><mover><mrow><mi>ϕ</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow><mrow><mn>2</mn></mrow></msup></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> of the equivalent scalar field representing dark energy as functions of redshift <span><math><mi>z</mi></math></span>.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"121 ","pages":"Article 102462"},"PeriodicalIF":2.1,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895110","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}

引用次数: 0

Unraveling the broadband spectrum of B2 1308+326: A clue to its high energy emission mechanism 解开B2 1308+326的宽带频谱：其高能量发射机制的线索

IF 2.1 4区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

New Astronomy

Pub Date : 2025-08-11 DOI: 10.1016/j.newast.2025.102463

Athar A. Dar , Zahir Shah , Sunder Sahayanathan , Naseer Iqbal , Subir Bhattacharyya , Debanjan Bose

The Flat Spectrum Radio Quasar (FSRQ) B2 1308+326 was in its highest

γ

-ray flaring state during 60260-60310 MJD. During this period, the source was detected in very high energy (VHE) by the large-sized telescope (LST-1). We conducted a detailed broadband spectral study of this source using the simultaneous data available in optical/UV, X-ray, and

γ

-ray bands. For the broadband spectral study, we select two gamma-ray high-flux states (59750-59800 MJD, 60260-60310 MJD) and one low-flux state (59250-59320 MJD). The broadband spectral energy distribution (SED) during these flux states are studied under leptonic emission scenario involving synchrotron, synchrotron self Compton (SSC) and external Compton (EC) processes. During the epochs, 59750-59800 MJD (high-flux state) and 59250-59320 MJD (low-flux state), the broadband SED is well fitted under the leptonic emission model while satisfying the equipartition between the particle and the magnetic field energy densities. However, the flaring state (60260-60310 MJD), during which the source showed VHE emission, demands deviation from equipartition by a factor of

\sim 14

for the successful reproduction of the SED. This suggests the system may be under non-equilibrium condition or alternatively additional emission components may be active.

平谱射电类星体B2 1308+326在60260-60310 MJD期间处于其最高的γ射线耀斑状态。在此期间，大型望远镜（LST-1）以甚高能量（VHE）探测到该源。我们利用光学/紫外、x射线和γ射线波段的同时数据对该源进行了详细的宽带光谱研究。为了进行宽带光谱研究，我们选择了两个伽马射线高通量态（59750-59800 MJD, 60260-60310 MJD）和一个低通量态（59250-59320 MJD）。研究了在同步加速器、同步加速器自康普顿（SSC）过程和外康普顿（EC）过程的轻子发射情况下这些磁通状态下的宽带频谱能量分布。在59750 ~ 59800 MJD（高通量态）和59250 ~ 59320 MJD（低通量态）时期，宽带SED在轻子发射模型下拟合良好，同时满足粒子与磁场能量密度的均分。然而，在燃烧状态（60260-60310 MJD），在此期间源显示出VHE发射，需要偏离均分约14倍才能成功复制SED。这表明系统可能处于非平衡状态，或者额外的发射成分可能是活跃的。

{"title":"Unraveling the broadband spectrum of B2 1308+326: A clue to its high energy emission mechanism","authors":"Athar A. Dar , Zahir Shah , Sunder Sahayanathan , Naseer Iqbal , Subir Bhattacharyya , Debanjan Bose","doi":"10.1016/j.newast.2025.102463","DOIUrl":"10.1016/j.newast.2025.102463","url":null,"abstract":"<div><div>The Flat Spectrum Radio Quasar (FSRQ) B2 1308+326 was in its highest <span><math><mi>γ</mi></math></span>-ray flaring state during 60260-60310 MJD. During this period, the source was detected in very high energy (VHE) by the large-sized telescope (LST-1). We conducted a detailed broadband spectral study of this source using the simultaneous data available in optical/UV, X-ray, and <span><math><mi>γ</mi></math></span>-ray bands. For the broadband spectral study, we select two gamma-ray high-flux states (59750-59800 MJD, 60260-60310 MJD) and one low-flux state (59250-59320 MJD). The broadband spectral energy distribution (SED) during these flux states are studied under leptonic emission scenario involving synchrotron, synchrotron self Compton (SSC) and external Compton (EC) processes. During the epochs, 59750-59800 MJD (high-flux state) and 59250-59320 MJD (low-flux state), the broadband SED is well fitted under the leptonic emission model while satisfying the equipartition between the particle and the magnetic field energy densities. However, the flaring state (60260-60310 MJD), during which the source showed VHE emission, demands deviation from equipartition by a factor of <span><math><mrow><mo>∼</mo><mn>14</mn></mrow></math></span> for the successful reproduction of the SED. This suggests the system may be under non-equilibrium condition or alternatively additional emission components may be active.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"121 ","pages":"Article 102463"},"PeriodicalIF":2.1,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144830950","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}

引用次数: 0