Pub Date : 2024-11-18DOI: 10.1051/0004-6361/202449941
R. Niedziela, K. Murawski, S. Poedts
Context. This study was carried out in the context of chromosphere heating.Aims. This paper aims to discuss the evolution of driven slow magnetoacoustic waves (SMAWs) in the solar chromosphere modelled with a realistic ionisation profile and to consider their potential role in plasma heating and the generation of plasma outflows.Methods. Two-dimensional (2D) numerical simulations of the solar atmosphere are performed using the JOANNA code. The dynamic behaviour of the atmospheric plasma is governed by the two-fluid equations (with ionisation and recombination terms taken into account) for neutrals (hydrogen atoms) and ions (protons)+electrons. The initial atmosphere is described by a hydrostatic equilibrium (HE) supplemented by the Saha equation (SE) and embedded in a fanning magnetic field. This initial equilibrium is perturbed by a monochromatic driver which operates in the chromosphere on the vertical components of the ion and neutral velocities.Results. Our work shows that the HE+SE model results in time-averaged (net) plasma outflows in the top chromosphere, which are larger than their pure HE counterpart. The parametric studies demonstrate that the largest chromosphere temperature rise occurs for smaller wave driving periods. The plasma outflows exhibit the opposite trend, growing with the driver period.Conclusions. We find that the inclusion of the HE+SE plasma background plays a key role in the evolution of SMAWs in the solar atmosphere.
背景。这项研究是在色球加热的背景下进行的。本文旨在讨论太阳色球层中驱动慢磁声波（SMAWs）的演化，模拟了现实的电离轮廓，并考虑它们在等离子体加热和产生等离子体外流中的潜在作用。使用 JOANNA 代码对太阳大气进行二维（2D）数值模拟。大气等离子体的动态行为受中子（氢原子）和离子（质子）+电子的双流体方程（考虑了电离和重组项）支配。初始大气由静力学平衡（HE）描述，并辅以萨哈方程（SE），嵌入扇形磁场。这种初始平衡受到单色驱动器的扰动，该驱动器在色球层中对离子和中性速度的垂直分量起作用。我们的研究结果表明，HE+SE 模型会导致顶部色球层出现时间平均（净）等离子体外流，其规模大于纯 HE 模型。参数研究表明，在较小的波驱动周期内，色球层的温升最大。等离子体外流则表现出相反的趋势，随着驱动周期的增长而增长。我们发现 HE+SE 等离子体背景的加入在太阳大气中 SMAW 的演化过程中起着关键作用。
{"title":"Driven two-fluid slow magnetoacoustic waves in the solar chromosphere with a realistic ionisation profile","authors":"R. Niedziela, K. Murawski, S. Poedts","doi":"10.1051/0004-6361/202449941","DOIUrl":"https://doi.org/10.1051/0004-6361/202449941","url":null,"abstract":"<i>Context.<i/> This study was carried out in the context of chromosphere heating.<i>Aims.<i/> This paper aims to discuss the evolution of driven slow magnetoacoustic waves (SMAWs) in the solar chromosphere modelled with a realistic ionisation profile and to consider their potential role in plasma heating and the generation of plasma outflows.<i>Methods.<i/> Two-dimensional (2D) numerical simulations of the solar atmosphere are performed using the JOANNA code. The dynamic behaviour of the atmospheric plasma is governed by the two-fluid equations (with ionisation and recombination terms taken into account) for neutrals (hydrogen atoms) and ions (protons)+electrons. The initial atmosphere is described by a hydrostatic equilibrium (HE) supplemented by the Saha equation (SE) and embedded in a fanning magnetic field. This initial equilibrium is perturbed by a monochromatic driver which operates in the chromosphere on the vertical components of the ion and neutral velocities.<i>Results.<i/> Our work shows that the HE+SE model results in time-averaged (net) plasma outflows in the top chromosphere, which are larger than their pure HE counterpart. The parametric studies demonstrate that the largest chromosphere temperature rise occurs for smaller wave driving periods. The plasma outflows exhibit the opposite trend, growing with the driver period.<i>Conclusions.<i/> We find that the inclusion of the HE+SE plasma background plays a key role in the evolution of SMAWs in the solar atmosphere.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"36 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-18DOI: 10.1051/0004-6361/202346361
C. Romero, J. Milli, A.-M. Lagrange, R. De Rosa, S. Ertel, C. del Burgo
Context. High-contrast imaging observations mostly rely on angular differential imaging, a successful technique for detecting point-sources, such as planets. However, in the vicinity of the star (typically below 300 mas), this technique suffers from signal self-subtraction when there is not enough field rotation. Building large libraries of reference stars from archival data later used to optimally subtract the stellar halo is a powerful technique known as reference star differential imaging (RSDI) that can overcome this limitation.Aims. We aim at investigating new methods for creating reference libraries composed of multiple stars when applying reference star differential imaging to VLT/SPHERE data. We used for that purpose a data set from the SPHERE High Angular Resolution Debris Disk Survey (SHARDDS), composed of 55 targets observed in broad-band H with the InfraRed Dual-band Imager and Spectrograph (IRDIS) during 2015-2016, with a total of ~20 000 frames. We consider HD 206893, known to host a close-in bound substellar companion HD 206893 B, as a benchmark science target to demonstrate the improved sensitivity provided by this method.Methods. We created libraries of reference frames based on different image similarity metrics: the cosine distance between descriptors created by a convolutional neural network, the Pearson correlation coefficient, the Structural Similarity Index, the Strehl ratio, and raw contrast criteria. We used principal component analysis (PCA) to subtract the stellar halo and tested various normalization options.Results. We obtained the best signal-to-noise ratio (S/N) on HD 206893 B by using the Pearson correlation coefficient (PCC) applied to an annulus between 245 and 612 mas to select reference frames. The ten reference libraries with the highest S/N on the substellar companion HD 206893 B were all based on the PCC method, outperforming other similarity metrics. While the Strehl ratio is the environment variable most correlated to the contrast, it is insufficient to select similar images. We also show that having multiple reference stars in the reference library produces better results than using a single well-chosen reference star.Conclusions. Using the Pearson correlation computed on a specific area of interest to select reference frames is a promising alternative to improve the detectability of faint point-sources when applying reference star differential imaging. In the future, reducing all the data available in the SPHERE archive using this technique might offer interesting results in the search for previously undetected planets.
背景。高对比度成像观测主要依靠角差分成像，这是一种成功的探测点源（如行星）的技术。然而，在恒星附近（通常低于 300mas），如果没有足够的场旋转，这种技术就会受到信号自减的影响。从档案数据中建立大型参考恒星库，然后用于优化减去恒星晕，这是一种强大的技术，被称为参考恒星差分成像（RSDI），可以克服这一局限。我们的目的是研究在对 VLT/SPHERE 数据进行参考星差分成像时创建由多颗恒星组成的参考库的新方法。为此，我们使用了 SPHERE 高角分辨率碎片盘巡天（SHARDDS）的数据集，该数据集由 2015-2016 年期间用红外双波段成像仪和摄谱仪（IRDIS）在宽波段 H 波段观测到的 55 个目标组成，共约 20 000 帧。我们将HD 206893作为一个基准科学目标，以展示这种方法所提供的更高灵敏度。我们根据不同的图像相似性指标创建了参考帧库：卷积神经网络创建的描述符之间的余弦距离、皮尔逊相关系数、结构相似性指数、Strehl 比率和原始对比度标准。我们使用主成分分析（PCA）来减去恒星光环，并测试了各种归一化选项。我们使用皮尔逊相关系数（PCC）对 245 至 612 马斯之间的环形区域进行筛选，从而在 HD 206893 B 上获得了最佳信噪比（S/N）。在亚恒星伴星HD 206893 B上信噪比最高的十个参考库都是基于皮尔逊相关系数方法，优于其他相似性指标。虽然施特莱尔比是与对比度最相关的环境变量，但它不足以选出相似的图像。我们还表明，在参考库中拥有多个参考星比使用一个精心挑选的参考星能产生更好的结果。在应用参考星差分成像时，使用在特定感兴趣区域计算的皮尔逊相关性来选择参考帧是提高微弱点源可探测性的一种有前途的替代方法。今后，利用这种技术减少 SPHERE 档案中的所有可用数据，可能会为寻找以前未探测到的行星提供有趣的结果。
{"title":"Multiple reference star differential imaging with VLT/SPHERE","authors":"C. Romero, J. Milli, A.-M. Lagrange, R. De Rosa, S. Ertel, C. del Burgo","doi":"10.1051/0004-6361/202346361","DOIUrl":"https://doi.org/10.1051/0004-6361/202346361","url":null,"abstract":"<i>Context<i/>. High-contrast imaging observations mostly rely on angular differential imaging, a successful technique for detecting point-sources, such as planets. However, in the vicinity of the star (typically below 300 mas), this technique suffers from signal self-subtraction when there is not enough field rotation. Building large libraries of reference stars from archival data later used to optimally subtract the stellar halo is a powerful technique known as reference star differential imaging (RSDI) that can overcome this limitation.<i>Aims<i/>. We aim at investigating new methods for creating reference libraries composed of multiple stars when applying reference star differential imaging to VLT/SPHERE data. We used for that purpose a data set from the SPHERE High Angular Resolution Debris Disk Survey (SHARDDS), composed of 55 targets observed in broad-band H with the InfraRed Dual-band Imager and Spectrograph (IRDIS) during 2015-2016, with a total of ~20 000 frames. We consider HD 206893, known to host a close-in bound substellar companion HD 206893 B, as a benchmark science target to demonstrate the improved sensitivity provided by this method.<i>Methods<i/>. We created libraries of reference frames based on different image similarity metrics: the cosine distance between descriptors created by a convolutional neural network, the Pearson correlation coefficient, the Structural Similarity Index, the Strehl ratio, and raw contrast criteria. We used principal component analysis (PCA) to subtract the stellar halo and tested various normalization options.<i>Results<i/>. We obtained the best signal-to-noise ratio (S/N) on HD 206893 B by using the Pearson correlation coefficient (PCC) applied to an annulus between 245 and 612 mas to select reference frames. The ten reference libraries with the highest S/N on the substellar companion HD 206893 B were all based on the PCC method, outperforming other similarity metrics. While the Strehl ratio is the environment variable most correlated to the contrast, it is insufficient to select similar images. We also show that having multiple reference stars in the reference library produces better results than using a single well-chosen reference star.<i>Conclusions<i/>. Using the Pearson correlation computed on a specific area of interest to select reference frames is a promising alternative to improve the detectability of faint point-sources when applying reference star differential imaging. In the future, reducing all the data available in the SPHERE archive using this technique might offer interesting results in the search for previously undetected planets.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"250 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-18DOI: 10.1051/0004-6361/202451396
L. Mousset, E. Allys, M. A. Price, J. Aumont, J.-M. Delouis, L. Montier, J. D. McEwen
Scattering transforms are a new type of summary statistics recently developed for the study of highly non-Gaussian processes, which have been shown to be very promising for astrophysical studies. In particular, they allow one to build generative models of complex non-linear fields from a limited amount of data and have been used as the basis of new statistical component separation algorithms. In the context of upcoming cosmological surveys, such as LiteBIRD for the cosmic microwave background polarisation or the Vera C. Rubin Observatory and the Euclid space telescope for study of the large-scale structures of the Universe, extending these tools to spherical data is necessary. In this work, we developed scattering transforms on the sphere and focused on the construction of maximum-entropy generative models of several astrophysical fields. We constructed, from a single target field, generative models of homogeneous astrophysical and cosmological fields, whose samples were quantitatively compared to the target fields using common statistics (power spectrum, pixel probability density function, and Minkowski functionals). Our sampled fields agree well with the target fields, both statistically and visually. We conclude, therefore, that these generative models open up a wide range of new applications for future astrophysical and cosmological studies, particularly those for which very little simulated data is available.
散射变换是最近为研究高度非高斯过程而开发的一种新型汇总统计，已被证明在天体物理研究中大有可为。特别是，它们允许人们从有限的数据量中建立复杂非线性场的生成模型，并被用作新的统计成分分离算法的基础。在即将开展的宇宙学调查中，如用于宇宙微波背景极化的 LiteBIRD 或用于研究宇宙大尺度结构的 Vera C. Rubin 天文台和 Euclid 空间望远镜，有必要将这些工具扩展到球形数据。在这项工作中，我们开发了球面散射变换，并重点构建了几个天体物理场的最大熵生成模型。我们从单个目标场构建了同质天体物理场和宇宙学场的生成模型，并使用通用统计（功率谱、像素概率密度函数和闵科夫斯基函数）将其样本与目标场进行了定量比较。我们的采样场与目标场在统计和视觉上都非常吻合。因此，我们得出结论，这些生成模型为未来的天体物理学和宇宙学研究开辟了广泛的新应用领域，尤其是那些模拟数据非常少的领域。
{"title":"Generative models of astrophysical fields with scattering transforms on the sphere","authors":"L. Mousset, E. Allys, M. A. Price, J. Aumont, J.-M. Delouis, L. Montier, J. D. McEwen","doi":"10.1051/0004-6361/202451396","DOIUrl":"https://doi.org/10.1051/0004-6361/202451396","url":null,"abstract":"Scattering transforms are a new type of summary statistics recently developed for the study of highly non-Gaussian processes, which have been shown to be very promising for astrophysical studies. In particular, they allow one to build generative models of complex non-linear fields from a limited amount of data and have been used as the basis of new statistical component separation algorithms. In the context of upcoming cosmological surveys, such as LiteBIRD for the cosmic microwave background polarisation or the <i>Vera C. Rubin<i/> Observatory and the <i>Euclid<i/> space telescope for study of the large-scale structures of the Universe, extending these tools to spherical data is necessary. In this work, we developed scattering transforms on the sphere and focused on the construction of maximum-entropy generative models of several astrophysical fields. We constructed, from a single target field, generative models of homogeneous astrophysical and cosmological fields, whose samples were quantitatively compared to the target fields using common statistics (power spectrum, pixel probability density function, and Minkowski functionals). Our sampled fields agree well with the target fields, both statistically and visually. We conclude, therefore, that these generative models open up a wide range of new applications for future astrophysical and cosmological studies, particularly those for which very little simulated data is available.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"17 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-18DOI: 10.1051/0004-6361/202450879
Xiandi Zeng, Hong Tang, Xiongyao Li, Chuanjiao Zhou, Sen Hu, Xiaojia Zeng, Wen Yu, Yuanyun Wen, Yanxue Wu, Bing Mo, Jianzhong Liu, Yong Fu
Context. The solar wind protons implanted in silicate material and combined with oxygen are considered crucial for forming OH/H2O on the Moon and other airless bodies. This process may also have contributed to hydrogen delivery to planetary interiors through the accretion of micrometre-sized dust and planetesimals during early stages of the Solar System.Aims. This paper experimentally investigates the depth distribution of solar wind protons in silicate materials and explores the mechanisms that influence this profile.Methods. We simulated solar wind irradiation by implanting 3 keV D2+ ions in three typical silicates (olivine, pyroxene, and plagio-clase) at a fluence of ~1.4 × 1017 ions/cm2. Fourier transform infrared spectroscopy was used to analyse chemical bond changes, while transmission electron microscopy (TEM) characterised microstructural modifications. Nanoscale secondary ion mass spectrometry (NanoSIMS) was employed to measure the D/16O ratio and determine the depth distribution of implanted deuterium.Results. The newly produced OD band (at 2400-2800 cm−1 ) in the infrared spectrum reveals the formation of O–D bonds in the irradiated silicates. The TEM and NanoSIMS results suggest that over 73% of the implanted D accumulated in fully amorphous rims with a depth of 70 nm, while 25% extended inwards to ~190 nanometres, resulting in partial amorphisation. The distribution of these deuterium particles is governed by the collision processes of the implanted particles, which involve factors such as initial energy loss, cascade collisions, and channelling effects. Furthermore, up to 2% of the total implanted D penetrated the intact lattice via diffusion, reaching depths ranging from hundreds of nanometres to several micrometres.Conclusions. Our results suggest that implanted solar wind protons can be retained in silicate interiors, which may significantly affect the hydrogen isotopic composition in extraterrestrial samples and imply an important source of hydrogen during the formation of terrestrial planets.
{"title":"Depth profiling of implanted D+ in silicates: Contribution of solar wind protons to water in the Moon and terrestrial planets","authors":"Xiandi Zeng, Hong Tang, Xiongyao Li, Chuanjiao Zhou, Sen Hu, Xiaojia Zeng, Wen Yu, Yuanyun Wen, Yanxue Wu, Bing Mo, Jianzhong Liu, Yong Fu","doi":"10.1051/0004-6361/202450879","DOIUrl":"https://doi.org/10.1051/0004-6361/202450879","url":null,"abstract":"<i>Context<i/>. The solar wind protons implanted in silicate material and combined with oxygen are considered crucial for forming OH/H<sub>2<sub/>O on the Moon and other airless bodies. This process may also have contributed to hydrogen delivery to planetary interiors through the accretion of micrometre-sized dust and planetesimals during early stages of the Solar System.<i>Aims<i/>. This paper experimentally investigates the depth distribution of solar wind protons in silicate materials and explores the mechanisms that influence this profile.<i>Methods<i/>. We simulated solar wind irradiation by implanting 3 keV D<sub>2<sub/><sup>+<sup/> ions in three typical silicates (olivine, pyroxene, and plagio-clase) at a fluence of ~1.4 × 10<sup>17<sup/> ions/cm<sup>2<sup/>. Fourier transform infrared spectroscopy was used to analyse chemical bond changes, while transmission electron microscopy (TEM) characterised microstructural modifications. Nanoscale secondary ion mass spectrometry (NanoSIMS) was employed to measure the D/<sup>16<sup/>O ratio and determine the depth distribution of implanted deuterium.<i>Results<i/>. The newly produced OD band (at 2400-2800 cm<sup>−1<sup/> ) in the infrared spectrum reveals the formation of O–D bonds in the irradiated silicates. The TEM and NanoSIMS results suggest that over 73% of the implanted D accumulated in fully amorphous rims with a depth of 70 nm, while 25% extended inwards to ~190 nanometres, resulting in partial amorphisation. The distribution of these deuterium particles is governed by the collision processes of the implanted particles, which involve factors such as initial energy loss, cascade collisions, and channelling effects. Furthermore, up to 2% of the total implanted D penetrated the intact lattice via diffusion, reaching depths ranging from hundreds of nanometres to several micrometres.<i>Conclusions<i/>. Our results suggest that implanted solar wind protons can be retained in silicate interiors, which may significantly affect the hydrogen isotopic composition in extraterrestrial samples and imply an important source of hydrogen during the formation of terrestrial planets.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"62 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-15DOI: 10.1051/0004-6361/202348164
Bernhard Baumschlager, Sijing Shen, James W. Wadsley
Radiation from stars and active galactic nuclei (AGN) plays an important role in galaxy formation and evolution, and profoundly transforms the intergalactic, circumgalactic, and interstellar medium (IGM, CGM, and ISM). On-the-fly radiative transfer (RT) has started being incorporated in cosmological simulations, but the complex evolving radiation spectra are often crudely approximated with a small number of broad bands with piece-wise constant intensity and a fixed photo-ionisation cross-section. Such a treatment is unable to capture the changes to the spectrum as light is absorbed while it propagates through a medium with non-zero opacity. This can lead to large errors in photo-ionisation and heating rates. In this work we present a novel approach of discretising the radiation field at discrete photon energies, at the edges of the typically used photo-ionising bands, in order to capture the power-law slope of the radiation field. In combination with power-law approximations for the photo-ionisation cross-sections, this model allows us to self-consistently combine radiation from sources with different spectra and accurately follow the ionisation states of primordial and metal species through time. The method is implemented in GASOLINE2 in connection with TREVR2, a fast reverse ray tracing algorithm with 𝒪(Nactive log2N) scaling. We compare our new piece-wise power-law reconstruction to the piece-wise constant method in calculating the primordial chemistry photo-ionisation and heating rates under an evolving UV background (UVB) and stellar spectrum, and find that our method reduces errors significantly, by up to two orders of magnitude in the case of HeII ionisation. We apply our new spectral reconstruction method in RT post-processing of a cosmological zoom-in simulation, MUGS2 g1536, including radiation from stars and a live UVB, and find a significant increase in total neutral hydrogen (HI) mass in the ISM and the CGM due to shielding of the UVB and a low escape fraction of the stellar radiation. This demonstrates the importance of RT and an accurate spectral approximation in simulating the CGM-galaxy ecosystem.
{"title":"Spectral reconstruction for radiation hydrodynamic simulations of galaxy evolution","authors":"Bernhard Baumschlager, Sijing Shen, James W. Wadsley","doi":"10.1051/0004-6361/202348164","DOIUrl":"https://doi.org/10.1051/0004-6361/202348164","url":null,"abstract":"Radiation from stars and active galactic nuclei (AGN) plays an important role in galaxy formation and evolution, and profoundly transforms the intergalactic, circumgalactic, and interstellar medium (IGM, CGM, and ISM). On-the-fly radiative transfer (RT) has started being incorporated in cosmological simulations, but the complex evolving radiation spectra are often crudely approximated with a small number of broad bands with piece-wise constant intensity and a fixed photo-ionisation cross-section. Such a treatment is unable to capture the changes to the spectrum as light is absorbed while it propagates through a medium with non-zero opacity. This can lead to large errors in photo-ionisation and heating rates. In this work we present a novel approach of discretising the radiation field at discrete photon energies, at the edges of the typically used photo-ionising bands, in order to capture the power-law slope of the radiation field. In combination with power-law approximations for the photo-ionisation cross-sections, this model allows us to self-consistently combine radiation from sources with different spectra and accurately follow the ionisation states of primordial and metal species through time. The method is implemented in GASOLINE2 in connection with TREVR2, a fast reverse ray tracing algorithm with 𝒪(<i>N<i/><sub>active<sub/> log<sub>2<sub/> <i>N<i/>) scaling. We compare our new piece-wise power-law reconstruction to the piece-wise constant method in calculating the primordial chemistry photo-ionisation and heating rates under an evolving UV background (UVB) and stellar spectrum, and find that our method reduces errors significantly, by up to two orders of magnitude in the case of HeII ionisation. We apply our new spectral reconstruction method in RT post-processing of a cosmological zoom-in simulation, MUGS2 g1536, including radiation from stars and a live UVB, and find a significant increase in total neutral hydrogen (HI) mass in the ISM and the CGM due to shielding of the UVB and a low escape fraction of the stellar radiation. This demonstrates the importance of RT and an accurate spectral approximation in simulating the CGM-galaxy ecosystem.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"10 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-15DOI: 10.1051/0004-6361/202451443
Miguel Araya
Context. Recently, the Nereides nebula was discovered through deep optical emission line observations and was classified as a supernova remnant (SNR) candidate, G107.7−5.1.Aims. Since very little is known about this SNR, we have looked at several archival datasets to better understand the environment and properties of the object.Methods. We present a detailed analysis of the gamma-ray emission detected by the Fermi Large Area Telescope in the region of the nebula. A model of the nonthermal emission is presented that allows us to derive the particle distribution responsible for the gamma rays. We also use molecular gas and atomic hydrogen observations to try to constrain the source age and distance.Results. An extended (∼2°) GeV source coincident with the location of the nebula is found. The nonthermal emission has a hard spectrum and is detected up to ∼100 GeV, confirming the SNR nature of this object. The GeV properties of G107.7−5.1 are similar to those of other SNRs such as G150.3 + 4.5, and it likely expands in a relatively low-density medium. The Nereides nebula is one more example of a growing population of dim SNRs detected at high energies. A simple leptonic model is able to account for the gamma-ray emission. Standard SNR evolutionary models constrain the age to be in the 10 − 50 kyr range, which is consistent with estimates of the maximum particle energy obtained from GeV observations. However, more detailed observations of the source should be carried out to better understand its properties.
{"title":"Nonthermal GeV emission from the Nereides nebula: Confirming the nature of the supernova remnant G107.7−5.1","authors":"Miguel Araya","doi":"10.1051/0004-6361/202451443","DOIUrl":"https://doi.org/10.1051/0004-6361/202451443","url":null,"abstract":"<i>Context.<i/> Recently, the Nereides nebula was discovered through deep optical emission line observations and was classified as a supernova remnant (SNR) candidate, G107.7−5.1.<i>Aims.<i/> Since very little is known about this SNR, we have looked at several archival datasets to better understand the environment and properties of the object.<i>Methods.<i/> We present a detailed analysis of the gamma-ray emission detected by the <i>Fermi<i/> Large Area Telescope in the region of the nebula. A model of the nonthermal emission is presented that allows us to derive the particle distribution responsible for the gamma rays. We also use molecular gas and atomic hydrogen observations to try to constrain the source age and distance.<i>Results.<i/> An extended (∼2°) GeV source coincident with the location of the nebula is found. The nonthermal emission has a hard spectrum and is detected up to ∼100 GeV, confirming the SNR nature of this object. The GeV properties of G107.7−5.1 are similar to those of other SNRs such as G150.3 + 4.5, and it likely expands in a relatively low-density medium. The Nereides nebula is one more example of a growing population of dim SNRs detected at high energies. A simple leptonic model is able to account for the gamma-ray emission. Standard SNR evolutionary models constrain the age to be in the 10 − 50 kyr range, which is consistent with estimates of the maximum particle energy obtained from GeV observations. However, more detailed observations of the source should be carried out to better understand its properties.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"10 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-15DOI: 10.1051/0004-6361/202451297
Zheng Cao, Peter G. Jonker, Sixiang Wen, Ann I. Zabludoff
The origin of the most luminous subclass of the fast blue optical transients (LFBOTs) is still unknown. We present an X-ray spectral analysis of AT2018cow – the LFBOT archetype – using NuSTAR, Swift, and XMM-Newton data. The source spectrum can be explained by the presence of a slim accretion disk, and we find that the mass accretion rate decreases to sub–Eddington levels ≳200 days after the source’s discovery. Applying our slim-disk model to data obtained at multiple observational epochs, we constrain the mass of the central compact object in AT2018cow to be log( at the 68% confidence level. Our mass measurement is independent from, but consistent with, the results from previously employed methods. The mass constraint is consistent with both the tidal disruption and the black hole–star merger scenarios, if the latter model can be extrapolated to the measured black hole mass. Our work provides evidence for an accreting intermediate–mass black hole (102 − 106M⊙) as the central engine in AT2018cow, and, by extension, in LFBOT sources similar to AT2018cow.
{"title":"Slim-disk modeling reveals an accreting intermediate-mass black hole in the luminous fast blue optical transient AT2018cow","authors":"Zheng Cao, Peter G. Jonker, Sixiang Wen, Ann I. Zabludoff","doi":"10.1051/0004-6361/202451297","DOIUrl":"https://doi.org/10.1051/0004-6361/202451297","url":null,"abstract":"The origin of the most luminous subclass of the fast blue optical transients (LFBOTs) is still unknown. We present an X-ray spectral analysis of AT2018cow – the LFBOT archetype – using <i>NuSTAR<i/>, <i>Swift<i/>, and <i>XMM-Newton<i/> data. The source spectrum can be explained by the presence of a slim accretion disk, and we find that the mass accretion rate decreases to sub–Eddington levels ≳200 days after the source’s discovery. Applying our slim-disk model to data obtained at multiple observational epochs, we constrain the mass of the central compact object in AT2018cow to be log( at the 68% confidence level. Our mass measurement is independent from, but consistent with, the results from previously employed methods. The mass constraint is consistent with both the tidal disruption and the black hole–star merger scenarios, if the latter model can be extrapolated to the measured black hole mass. Our work provides evidence for an accreting intermediate–mass black hole (10<sup>2<sup/> − 10<sup>6<sup/> <i>M<i/><sub>⊙<sub/>) as the central engine in AT2018cow, and, by extension, in LFBOT sources similar to AT2018cow.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Context. KIC 10685175 is a roAp star whose polar magnetic field is predicted to be 6 kG through a nonadiabatic axisymmetric pulsation theoretical model.Aims. In this work, we aim to measure the magnetic field strength of KIC 10685175 using high-resolution spectropolarimetric observations, and compare it with the one predicted by the theoretical model.Methods. Two high-resolution unpolarized spectra have been analyzed to ascertain the presence of magnetically split lines and derive the iron abundance of this star through equivalent width measurements of 10 Fe lines. One polarized spectrum has been used to measure the mean longitudinal magnetic field with the least-squares deconvolution technique. Further, to examine the presence of chemical spots on the stellar surface, we have measured the mean longitudinal magnetic fields using different lines belonging to different elements.Results. From the study of two high-resolution unpolarized spectra, we obtained the spectroscopic atmospheric parameters including the effective temperature (Teff), surface gravity (log 𝑔), iron abundance ([Fe/H]), abundance ratio of alpha elements to iron ([α/Fe]), and micro-turbulent velocity (Vmic). The final result is [Teff, log g, [Fe/H], [α/Fe], Vmic)]=[8250 ± 200 K, 4.4 ± 0.1, −0.4 ± 0.2, 0.16 ± 0.1, 1.73 ± 0.2 km s−1]. Although the Fe absorption lines appear relatively weak in comparison to typical Ap stars with similar Teff, the lines belonging to rare earth elements (Eu and Nd) are stronger than those in chemically normal stars, indicating the peculiar nature of KIC 10685175. The mean longitudinal magnetic field, 〈Bℓ〉 = −226 ± 39 G, was measured in the polarized spectrum, but magnetically split lines were not detected. No significant line profile variability is evident in our spectra. Also, the longitudinal magnetic field strengths measured using line masks constructed for different elements are rather similar. Due to the poor rotation phase coverage of our data, additional spectroscopic and polarimetric observations are needed to allow us to come to any conclusions about the inhomogeneous element distribution over the stellar surface.Conclusions. The estimated polar magnetic field is 4.8 ± 0.8 kG, which is consistent with the predicted polar magnetic field strength of about 6kG within 3σ. This work therefore provides support for the pulsation theoretical model.
{"title":"Magnetic field of the roAp star KIC 10685175: Observations versus theory","authors":"Fangfei Shi, Huawei Zhang, Swetlana Hubrig, Silva Järvinen, Huiling Chen, Tianqi Cang, Jianning Fu, Donald Kurtz","doi":"10.1051/0004-6361/202451417","DOIUrl":"https://doi.org/10.1051/0004-6361/202451417","url":null,"abstract":"<i>Context<i/>. KIC 10685175 is a roAp star whose polar magnetic field is predicted to be 6 kG through a nonadiabatic axisymmetric pulsation theoretical model.<i>Aims<i/>. In this work, we aim to measure the magnetic field strength of KIC 10685175 using high-resolution spectropolarimetric observations, and compare it with the one predicted by the theoretical model.<i>Methods<i/>. Two high-resolution unpolarized spectra have been analyzed to ascertain the presence of magnetically split lines and derive the iron abundance of this star through equivalent width measurements of 10 Fe lines. One polarized spectrum has been used to measure the mean longitudinal magnetic field with the least-squares deconvolution technique. Further, to examine the presence of chemical spots on the stellar surface, we have measured the mean longitudinal magnetic fields using different lines belonging to different elements.<i>Results<i/>. From the study of two high-resolution unpolarized spectra, we obtained the spectroscopic atmospheric parameters including the effective temperature (<i>T<i/><sub>eff<sub/>), surface gravity (log 𝑔), iron abundance ([Fe/H]), abundance ratio of alpha elements to iron ([<i>α<i/>/Fe]), and micro-turbulent velocity (<i>V<i/><sub><i>mic<i/><sub/>). The final result is [<i>T<i/><sub>eff<sub/>, log g, [Fe/H], [<i>α<i/>/Fe], <i>V<i/><sub><i>mic<i/><sub/>)]=[8250 ± 200 K, 4.4 ± 0.1, −0.4 ± 0.2, 0.16 ± 0.1, 1.73 ± 0.2 km s<sup>−1<sup/>]. Although the Fe absorption lines appear relatively weak in comparison to typical Ap stars with similar <i>T<i/><sub>eff<sub/>, the lines belonging to rare earth elements (Eu and Nd) are stronger than those in chemically normal stars, indicating the peculiar nature of KIC 10685175. The mean longitudinal magnetic field, 〈<i>B<i/><sub><i>ℓ<i/><sub/>〉 = −226 ± 39 G, was measured in the polarized spectrum, but magnetically split lines were not detected. No significant line profile variability is evident in our spectra. Also, the longitudinal magnetic field strengths measured using line masks constructed for different elements are rather similar. Due to the poor rotation phase coverage of our data, additional spectroscopic and polarimetric observations are needed to allow us to come to any conclusions about the inhomogeneous element distribution over the stellar surface.<i>Conclusions<i/>. The estimated polar magnetic field is 4.8 ± 0.8 kG, which is consistent with the predicted polar magnetic field strength of about 6kG within 3<i>σ<i/>. This work therefore provides support for the pulsation theoretical model.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"31 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-15DOI: 10.1051/0004-6361/202451226
C. López-Sanjuan, P.-E. Tremblay, M. W. O’Brien, D. Spinoso, A. Ederoclite, H. Vázquez Ramió, A. J. Cenarro, A. Marín-Franch, T. Civera, J. M. Carrasco, B. T. Gänsicke, N. P. Gentile Fusillo, A. Hernán-Caballero, M. A. Hollands, A. del Pino, H. Domínguez Sánchez, J. A. Fernández-Ontiveros, F. M. Jiménez-Esteban, A. Rebassa-Mansergas, L. Schmidtobreick, R. E. Angulo, D. Cristóbal-Hornillos, R. A. Dupke, C. Hernández-Monteagudo, M. Moles, L. Sodré, J. Varela
Aims. We used the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2) photometry in 12 optical bands over 2176 deg2 to estimate the fraction of white dwarfs with the presence of Ca II H+K absorption along the cooling sequence.Methods. We compared the J-PLUS photometry against metal-free theoretical models to estimate the equivalent width in the J0395 passband of 10 nm centered at 395 nm (EWJ0395), a proxy to detect calcium absorption. A total of 4399 white dwarfs with effective temperatures within 30 000 > Teff > 5500 K and masses of M > 0.45 M⊙ were analyzed. Their EWJ0395 distribution was modeled using two populations, corresponding to polluted and non-polluted systems, to estimate the fraction of calcium white dwarfs (fCa) as a function of Teff. The probability of each individual white dwarf presenting calcium absorption, pCa, was also computed.Results. The comparison of EWJ0395 with both the measured Ca/He abundance and the identification of metal pollution from spectroscopy shows that EWJ0395 correlates with the presence of Ca II H+K absorption. The fraction of calcium white dwarfs changes along the cooling sequence, increasing from fCa ≈ 0 at Teff = 13 500 K to fCa ≈ 0.15 at Teff = 5500 K. This trend reflects the selection function of calcium white dwarfs in the optical. We compare our results with the fractions derived from the 40 pc spectroscopic sample and from Sloan Digital Sky Survey (SDSS) spectra. The trend found in J-PLUS observations is also present in the 40 pc sample; however, SDSS shows a deficit of metal-polluted objects at Teff < 12 000 K. Finally, we found 39 white dwarfs with pCa > 0.99. Twenty of them have spectra presented in previous studies, whereas we obtained follow-up spectroscopic observations for six additional targets. These 26 objects were all confirmed as metal-polluted systems.Conclusions. The J-PLUS optical data provide a robust statistical measurement for the presence of Ca II H+K absorption in white dwarfs. We find a 15 ± 3% increase in the fraction of calcium white dwarfs from Teff = 13 500 K to 5500 K, which reflects their selection function in the optical from the total population of metal-polluted systems.
目的我们利用 Javalambre 测光局域宇宙巡天（J-PLUS）第二次数据发布（DR2）中超过 2176 deg2 的 12 个光学波段的测光结果，来估算沿冷却序列存在 Ca II H+K 吸收的白矮星的比例。我们将J-PLUS光度测量与无金属理论模型进行了比较，以估算以395 nm为中心的J0395通带（EWJ0395）中10 nm的等效宽度。共分析了 4399 个有效温度在 30 000 > Teff > 5500 K 范围内、质量 M > 0.45 M⊙的白矮星。它们的 EWJ0395 分布是用两个种群来模拟的，分别对应于污染和非污染系统，以估算钙白矮星的比例（fCa）与 Teff 的函数关系。同时还计算了每个白矮星出现钙吸收的概率（pCa）。将 EWJ0395 与测量到的钙/氦丰度以及通过光谱鉴定出的金属污染进行比较后发现，EWJ0395 与 Ca II H+K 吸收的存在相关。钙白矮星的比例随着冷却序列的变化而变化，从Teff = 13 500 K时的fCa ≈ 0增加到Teff = 5500 K时的fCa ≈ 0.15。我们将我们的结果与 40 pc 光谱样本和斯隆数字巡天（SDSS）光谱得出的分数进行了比较。在J-PLUS观测中发现的趋势也出现在40 pc样本中；然而，SDSS显示Teff < 12 000 K的金属污染天体数量不足。其中 20 个天体的光谱已在以前的研究中公布，而我们又获得了另外 6 个目标的后续光谱观测数据。这 26 个目标都被确认为金属污染系统。J-PLUS光学数据为白矮星中Ca II H+K吸收的存在提供了可靠的统计测量。我们发现，从Teff = 13 500 K到5500 K，钙白矮星的比例增加了15 ± 3%，这反映了它们从金属污染系统总体中的光学选择功能。
{"title":"J-PLUS: The fraction of calcium white dwarfs along the cooling sequence","authors":"C. López-Sanjuan, P.-E. Tremblay, M. W. O’Brien, D. Spinoso, A. Ederoclite, H. Vázquez Ramió, A. J. Cenarro, A. Marín-Franch, T. Civera, J. M. Carrasco, B. T. Gänsicke, N. P. Gentile Fusillo, A. Hernán-Caballero, M. A. Hollands, A. del Pino, H. Domínguez Sánchez, J. A. Fernández-Ontiveros, F. M. Jiménez-Esteban, A. Rebassa-Mansergas, L. Schmidtobreick, R. E. Angulo, D. Cristóbal-Hornillos, R. A. Dupke, C. Hernández-Monteagudo, M. Moles, L. Sodré, J. Varela","doi":"10.1051/0004-6361/202451226","DOIUrl":"https://doi.org/10.1051/0004-6361/202451226","url":null,"abstract":"<i>Aims<i/>. We used the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2) photometry in 12 optical bands over 2176 deg<sup>2<sup/> to estimate the fraction of white dwarfs with the presence of Ca II H+K absorption along the cooling sequence.<i>Methods<i/>. We compared the J-PLUS photometry against metal-free theoretical models to estimate the equivalent width in the <i>J<i/>0395 passband of 10 nm centered at 395 nm (EW<sub><i>J<i/>0395<sub/>), a proxy to detect calcium absorption. A total of 4399 white dwarfs with effective temperatures within 30 000 > <i>T<i/><sub>eff<sub/> > 5500 K and masses of <i>M<i/> > 0.45 <i>M<i/><sub>⊙<sub/> were analyzed. Their EW<sub><i>J<i/>0395<sub/> distribution was modeled using two populations, corresponding to polluted and non-polluted systems, to estimate the fraction of calcium white dwarfs (<i>f<i/><sub>Ca<sub/>) as a function of <i>T<i/><sub>eff<sub/>. The probability of each individual white dwarf presenting calcium absorption, <i>p<i/><sub>Ca<sub/>, was also computed.<i>Results<i/>. The comparison of EW<sub><i>J<i/>0395<sub/> with both the measured Ca/He abundance and the identification of metal pollution from spectroscopy shows that EW<sub><i>J<i/>0395<sub/> correlates with the presence of Ca II H+K absorption. The fraction of calcium white dwarfs changes along the cooling sequence, increasing from <i>f<i/><sub>Ca<sub/> ≈ 0 at <i>T<i/><sub>eff<sub/> = 13 500 K to f<sub>Ca<sub/> ≈ 0.15 at <i>T<i/><sub>eff<sub/> = 5500 K. This trend reflects the selection function of calcium white dwarfs in the optical. We compare our results with the fractions derived from the 40 pc spectroscopic sample and from Sloan Digital Sky Survey (SDSS) spectra. The trend found in J-PLUS observations is also present in the 40 pc sample; however, SDSS shows a deficit of metal-polluted objects at <i>T<i/><sub>eff<sub/> < 12 000 K. Finally, we found 39 white dwarfs with <i>p<i/>Ca > 0.99. Twenty of them have spectra presented in previous studies, whereas we obtained follow-up spectroscopic observations for six additional targets. These 26 objects were all confirmed as metal-polluted systems.<i>Conclusions<i/>. The J-PLUS optical data provide a robust statistical measurement for the presence of Ca II H+K absorption in white dwarfs. We find a 15 ± 3% increase in the fraction of calcium white dwarfs from <i>T<i/><sub>eff<sub/> = 13 500 K to 5500 K, which reflects their selection function in the optical from the total population of metal-polluted systems.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"22 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2024-11-15DOI: 10.1051/0004-6361/202450846
John Ellis, Malcolm Fairbairn, Gert Hütsi, Juan Urrutia, Ville Vaskonen, Hardi Veermäe
JWST observations have opened a new chapter in supermassive black hole (SMBH) studies, stimulating discussion of two puzzles: the abundance of high-z SMBHs and the fraction of dual active galactic nuclei (AGNs). We argue that the answers to these puzzles may be linked to an interpretation of the data on the nanohertz gravitational waves (GWs) discovered by NANOGrav and other pulsar timing arrays as SMBH binaries whose evolution is driven by interactions with their environments down to O(0.1 pc) separations. We show that the stellar mass-black hole mass correlations found in JWST data and in low-ɀ inactive galaxies are similar, and present a global fit to these data, excluding low-ɀ AGNs. Matching the NANOGrav and dual-AGN data requires that binary evolution due to environmental effects at separations below O(1 kpc) be rapid on cosmological timescales. According to this interpretation, the SMBHs in low-ɀ AGNs are the tip of the iceberg of a local SMBH population in mainly inactive galaxies. This interpretation is consistent with the ‘little red dots’ observed with JWST being AGNs, and would favour the observability of GW signals from black hole binaries in LISA and decihertz GW detectors.
{"title":"Consistency of JWST black hole observations with NANOGrav gravitational wave measurements","authors":"John Ellis, Malcolm Fairbairn, Gert Hütsi, Juan Urrutia, Ville Vaskonen, Hardi Veermäe","doi":"10.1051/0004-6361/202450846","DOIUrl":"https://doi.org/10.1051/0004-6361/202450846","url":null,"abstract":"JWST observations have opened a new chapter in supermassive black hole (SMBH) studies, stimulating discussion of two puzzles: the abundance of high-z SMBHs and the fraction of dual active galactic nuclei (AGNs). We argue that the answers to these puzzles may be linked to an interpretation of the data on the nanohertz gravitational waves (GWs) discovered by NANOGrav and other pulsar timing arrays as SMBH binaries whose evolution is driven by interactions with their environments down to <i>O<i/>(0.1 pc) separations. We show that the stellar mass-black hole mass correlations found in JWST data and in low-ɀ inactive galaxies are similar, and present a global fit to these data, excluding low-ɀ AGNs. Matching the NANOGrav and dual-AGN data requires that binary evolution due to environmental effects at separations below <i>O(<i/>1 kpc) be rapid on cosmological timescales. According to this interpretation, the SMBHs in low-ɀ AGNs are the tip of the iceberg of a local SMBH population in mainly inactive galaxies. This interpretation is consistent with the ‘little red dots’ observed with JWST being AGNs, and would favour the observability of GW signals from black hole binaries in LISA and decihertz GW detectors.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"172 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
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