Pub Date : 2025-02-18DOI: 10.1051/0004-6361/202453509
Cs. Kiss, N. Takács, Cs. E. Kalup, R. Szakáts, L. Molnár, E. Plachy, K. Sárneczky, R. Szabó, Gy. M. Szabó, A. Bódi, A. Pál
We report on the identification of the three fastest rotating Jovian trojans with reliable population assignments known to date, discovered using light curve data from the Transiting Exoplanet Satellite Survey mission and confirmed by Zwicky Transient Facility data. For two of our targets the rotation periods are moderately below the previously accepted ∼5 h Jovian trojan breakup limit (4.26 and 4.75 h); however, the rotation period of (13383) was found to be P = 2.926 h, leading to a density estimate of ρ ≈1.6 g cm−3, higher than the generally accepted ≲1 g cm−3 density limit of Jovian trojans. If associated with lower densities, this rotation rate requires considerable cohesion, of the order of a few kilopascals. The relatively high albedo (pV ≈ 0.11) and fast rotation suggest that (13383) may have undergone an energetic collision that spun up the body and exposed bright material to the surface.
{"title":"Three fast-rotating Jovian trojans identified by TESS set new population density limits","authors":"Cs. Kiss, N. Takács, Cs. E. Kalup, R. Szakáts, L. Molnár, E. Plachy, K. Sárneczky, R. Szabó, Gy. M. Szabó, A. Bódi, A. Pál","doi":"10.1051/0004-6361/202453509","DOIUrl":"https://doi.org/10.1051/0004-6361/202453509","url":null,"abstract":"We report on the identification of the three fastest rotating Jovian trojans with reliable population assignments known to date, discovered using light curve data from the Transiting Exoplanet Satellite Survey mission and confirmed by <i>Zwicky<i/> Transient Facility data. For two of our targets the rotation periods are moderately below the previously accepted ∼5 h Jovian trojan breakup limit (4.26 and 4.75 h); however, the rotation period of (13383) was found to be P = 2.926 h, leading to a density estimate of <i>ρ<i/> ≈1.6 g cm<sup>−3<sup/>, higher than the generally accepted ≲1 g cm<sup>−3<sup/> density limit of Jovian trojans. If associated with lower densities, this rotation rate requires considerable cohesion, of the order of a few kilopascals. The relatively high albedo (p<sub><i>V<i/><sub/> ≈ 0.11) and fast rotation suggest that (13383) may have undergone an energetic collision that spun up the body and exposed bright material to the surface.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"64 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435708","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 : 2025-02-18DOI: 10.1051/0004-6361/202452900
A. Taillard, R. Martín-Doménech, H. Carrascosa, J. A. Noble, G. M. Muñoz Caro, E. Dartois, D. Navarro-Almaida, B. Escribano, Á. Sánchez-Monge, A. Fuente
To date, gas phase observations of sulphur in dense interstellar environments have only constrained the molecular carriers of ~1% of its predicted cosmic abundance. An additional ~5% is known to be locked up in molecular solids in dense clouds, leaving the main reservoir of depleted sulphur in the solid phase yet to be identified. Overall, OCS is the only S-bearing molecule unambiguously detected in interstellar ices thus far with infrared telescopes, although an absorption feature of SO<sub>2<sub/> has been plausibly identified at 7.5 µm. The spectral resolution and sensitivity of the <i>James Webb<i/> Space Telescope (JWST) could make a substantial difference in detecting part of this missing sulphur. The wavelength coverage of the JWST includes vibrational absorption features of the S-carriers H<sub>2<sub/>S, OCS, SO<sub>2<sub/>, CS<sub>2<sub/>, SO, CS, and S<sub>8<sub/> are found. The aim of this study is to determine whether these molecules may be viable candidates for detection. We carried out new laboratory measurements of the IR absorption spectra of CS<sub>2<sub/> and S<sub>8<sub/> to update the IR band strength of the most intense CS<sub>2<sub/> absorption feature at 6.8 µm, as well as to determine that of S<sub>8<sub/> at 20.3 µm for the first time. These data, along with values previously reported in the literature for H<sub>2<sub/>S, OCS, and SO<sub>2<sub/>, allow us to evaluate which S-bearing species could be potentially detected with JWST in interstellar ices. Taking the literature abundances of the major ice species determined by previous IR observations towards starless cores, low-mass young stellar objects (LYSOs) and massive young stellar objects (MYSOs), we generated simulated IR spectra using the characteristics of the instruments on the JWST. Thus, we have been able to establish a case study for three stages of the star formation process. These spectra were simulated using a tool that produces synthetic ice spectra, with the aim of studying the feasibility of detecting S-bearing species with the JWST by artificially adding S-bearing molecules to the simulated spectra. We conclude that the detection of S-bearing molecules remains challenging due to a variety of parameters; principally, the overlap of absorption features with those of other species and the mixing of molecular species in the ice impacting the profile and central position of the targeted bands. Despite these obstacles, the detection of H<sub>2<sub/>S in dense clouds – and potentially SO<sub>2<sub/> in LYSOs and MYSOs – should be possible in regions with favourable physical and chemical conditions, but not necessarily in the same region. In contrast, the large allotrope S<sub>8<sub/> would remain undetected even in the unrealistic case that all the available sulphur atoms were involved in its formation. Although the sensitivity of JWST is insufficient to determine the sulphur budget in the solid state, the detection of (or setting of significant upper limits on
{"title":"Predicting the detectability of sulphur-bearing molecules in the solid phase with simulated spectra of JWST instruments","authors":"A. Taillard, R. Martín-Doménech, H. Carrascosa, J. A. Noble, G. M. Muñoz Caro, E. Dartois, D. Navarro-Almaida, B. Escribano, Á. Sánchez-Monge, A. Fuente","doi":"10.1051/0004-6361/202452900","DOIUrl":"https://doi.org/10.1051/0004-6361/202452900","url":null,"abstract":"To date, gas phase observations of sulphur in dense interstellar environments have only constrained the molecular carriers of ~1% of its predicted cosmic abundance. An additional ~5% is known to be locked up in molecular solids in dense clouds, leaving the main reservoir of depleted sulphur in the solid phase yet to be identified. Overall, OCS is the only S-bearing molecule unambiguously detected in interstellar ices thus far with infrared telescopes, although an absorption feature of SO<sub>2<sub/> has been plausibly identified at 7.5 µm. The spectral resolution and sensitivity of the <i>James Webb<i/> Space Telescope (JWST) could make a substantial difference in detecting part of this missing sulphur. The wavelength coverage of the JWST includes vibrational absorption features of the S-carriers H<sub>2<sub/>S, OCS, SO<sub>2<sub/>, CS<sub>2<sub/>, SO, CS, and S<sub>8<sub/> are found. The aim of this study is to determine whether these molecules may be viable candidates for detection. We carried out new laboratory measurements of the IR absorption spectra of CS<sub>2<sub/> and S<sub>8<sub/> to update the IR band strength of the most intense CS<sub>2<sub/> absorption feature at 6.8 µm, as well as to determine that of S<sub>8<sub/> at 20.3 µm for the first time. These data, along with values previously reported in the literature for H<sub>2<sub/>S, OCS, and SO<sub>2<sub/>, allow us to evaluate which S-bearing species could be potentially detected with JWST in interstellar ices. Taking the literature abundances of the major ice species determined by previous IR observations towards starless cores, low-mass young stellar objects (LYSOs) and massive young stellar objects (MYSOs), we generated simulated IR spectra using the characteristics of the instruments on the JWST. Thus, we have been able to establish a case study for three stages of the star formation process. These spectra were simulated using a tool that produces synthetic ice spectra, with the aim of studying the feasibility of detecting S-bearing species with the JWST by artificially adding S-bearing molecules to the simulated spectra. We conclude that the detection of S-bearing molecules remains challenging due to a variety of parameters; principally, the overlap of absorption features with those of other species and the mixing of molecular species in the ice impacting the profile and central position of the targeted bands. Despite these obstacles, the detection of H<sub>2<sub/>S in dense clouds – and potentially SO<sub>2<sub/> in LYSOs and MYSOs – should be possible in regions with favourable physical and chemical conditions, but not necessarily in the same region. In contrast, the large allotrope S<sub>8<sub/> would remain undetected even in the unrealistic case that all the available sulphur atoms were involved in its formation. Although the sensitivity of JWST is insufficient to determine the sulphur budget in the solid state, the detection of (or setting of significant upper limits on ","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"34 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435734","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 : 2025-02-18DOI: 10.1051/0004-6361/202452420
M. Latour, S. Kamann, S. Martocchia, T.-O. Husser, S. Saracino, S. Dreizler
Context. Multiple populations are ubiquitous in the old massive globular clusters (GCs) of the Milky Way. It is still unclear how they arose during the formation of a GC. The topic of iron and metallicity variations has recently attracted attention with the measurement of iron variations among the primordial population (P1) stars of Galactic GCs.Aims. We explore the relationship between the metallicity of the P1 stars on the red-giant branch (RGB) of Galactic GCs and their ∆F275W,F814W pseudo-color. We also measure the metallicity dispersion of P1 and P2 stars.Methods. We used the spectra of more than 8000 RGB stars in 21 Galactic GCs observed with the integral-field spectrograph MUSE to derive individual stellar metallicities, [M/H]. For each cluster, we used Hubble Space Telescope photometric catalogs to separate the stars into two main populations (P1 and P2). We measured the metallicity spread within the primordial population of each cluster by combining our metallicity measurements with the stars’ ∆F275W,F814W pseudo-color. We also derived metallicity dispersions (σ[M/H]) for the P1 and P2 stars of each GC.Results. In all but three GCs we find a significant correlation between the metallicity and the ∆F275W,F814W pseudo-color of the P1 stars: stars with larger ∆F275W,F814W have higher metallicities. We measure metallicity spreads that range from 0.03 to 0.24 dex and correlate with the GC masses. As for the intrinsic metallicity dispersions, when combining the P1 and P2 stars, we measure values ranging from 0.02 dex to 0.08 dex, which correlate very well with the GC masses. The two clusters that show the largest σ[M/H] are NGC 6388 and NGC 6441. The P2 stars have metallicity dispersions that are smaller than or equal to those of the P1 stars.Conclusions. We present a homogeneous spectroscopic characterization of the metallicities of the P1 and P2 stars in a set of 21 Galactic GCs. We find that both the metallicity spreads of the P1 stars (from the ∆F275W,F814W spread on the chromosome maps) and the metallicity dispersions (σ[M/H]) correlate with the GC masses, as predicted by some theoretical self-enrichment models presented in the literature.
{"title":"A stellar census in globular clusters with MUSE","authors":"M. Latour, S. Kamann, S. Martocchia, T.-O. Husser, S. Saracino, S. Dreizler","doi":"10.1051/0004-6361/202452420","DOIUrl":"https://doi.org/10.1051/0004-6361/202452420","url":null,"abstract":"<i>Context<i/>. Multiple populations are ubiquitous in the old massive globular clusters (GCs) of the Milky Way. It is still unclear how they arose during the formation of a GC. The topic of iron and metallicity variations has recently attracted attention with the measurement of iron variations among the primordial population (P1) stars of Galactic GCs.<i>Aims<i/>. We explore the relationship between the metallicity of the P1 stars on the red-giant branch (RGB) of Galactic GCs and their ∆<sub>F275W,F814W<sub/> pseudo-color. We also measure the metallicity dispersion of P1 and P2 stars.<i>Methods<i/>. We used the spectra of more than 8000 RGB stars in 21 Galactic GCs observed with the integral-field spectrograph MUSE to derive individual stellar metallicities, [M/H]. For each cluster, we used <i>Hubble<i/> Space Telescope photometric catalogs to separate the stars into two main populations (P1 and P2). We measured the metallicity spread within the primordial population of each cluster by combining our metallicity measurements with the stars’ ∆<sub>F275W,F814W<sub/> pseudo-color. We also derived metallicity dispersions (<i>σ<i/><sub>[M/H]<sub/>) for the P1 and P2 stars of each GC.<i>Results<i/>. In all but three GCs we find a significant correlation between the metallicity and the ∆<sub>F275W,F814W<sub/> pseudo-color of the P1 stars: stars with larger ∆<sub>F275W,F814W<sub/> have higher metallicities. We measure metallicity spreads that range from 0.03 to 0.24 dex and correlate with the GC masses. As for the intrinsic metallicity dispersions, when combining the P1 and P2 stars, we measure values ranging from 0.02 dex to 0.08 dex, which correlate very well with the GC masses. The two clusters that show the largest <i>σ<i/><sub>[M/H]<sub/> are NGC 6388 and NGC 6441. The P2 stars have metallicity dispersions that are smaller than or equal to those of the P1 stars.<i>Conclusions<i/>. We present a homogeneous spectroscopic characterization of the metallicities of the P1 and P2 stars in a set of 21 Galactic GCs. We find that both the metallicity spreads of the P1 stars (from the ∆<sub>F275W,F814W<sub/> spread on the chromosome maps) and the metallicity dispersions (<i>σ<i/><sub>[M/H]<sub/>) correlate with the GC masses, as predicted by some theoretical self-enrichment models presented in the literature.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435772","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 : 2025-02-18DOI: 10.1051/0004-6361/202452928
G. Castelló, M. Luna, J. Terradas
Context. Solar filament oscillations have been observed for many years, but recent advances in telescope capabilities now enable a daily monitoring of these periodic motions. This offers valuable insights into the structure of filaments. A systematic study of filament oscillations over the solar cycle can shed light on the evolution of the prominences. Only manual techniques were used so far to analyze these oscillations.Aims. This work serves as a proof of concept and demonstrates the effectiveness of convolutional neural networks (CNNs). These networks automatically detect filament oscillations by applying a power-spectrum analysis to Hα data from the GONG telescope network.Methods. The proposed technique studies periodic fluctuations in every pixel of the Hα data cubes. Using the Lomb-Scargle periodogram, we computed the power spectral density (PSD) of the dataset. The background noise fits a combination of red and white noise well. Using Bayesian statistics and Markov chain Monte Carlo (MCMC) algorithms, we fit the spectra and determined the confidence threshold of a given percentage to search for real oscillations. We built two CNN models to obtain the same results as with the MCMC approach.Results. We applied the CNN models to some observations reported in the literature to prove its reliability in detecting the same events as the classical methods. A day with events that were not previously reported was studied to determine the model capabilities beyond a controlled dataset that we can check with previous reports.Conclusions. CNNs prove to be a useful tool for studying solar filament oscillations using spectral techniques. The computing times are significantly reduced for results that are similar enough to the classical methods. This is a relevant step toward the automatic detection of filament oscillations.
{"title":"Fast Bayesian spectral analysis using convolutional neural networks: Applications to GONG Hα solar data","authors":"G. Castelló, M. Luna, J. Terradas","doi":"10.1051/0004-6361/202452928","DOIUrl":"https://doi.org/10.1051/0004-6361/202452928","url":null,"abstract":"<i>Context<i/>. Solar filament oscillations have been observed for many years, but recent advances in telescope capabilities now enable a daily monitoring of these periodic motions. This offers valuable insights into the structure of filaments. A systematic study of filament oscillations over the solar cycle can shed light on the evolution of the prominences. Only manual techniques were used so far to analyze these oscillations.<i>Aims<i/>. This work serves as a proof of concept and demonstrates the effectiveness of convolutional neural networks (CNNs). These networks automatically detect filament oscillations by applying a power-spectrum analysis to Hα data from the GONG telescope network.<i>Methods<i/>. The proposed technique studies periodic fluctuations in every pixel of the Hα data cubes. Using the Lomb-Scargle periodogram, we computed the power spectral density (PSD) of the dataset. The background noise fits a combination of red and white noise well. Using Bayesian statistics and Markov chain Monte Carlo (MCMC) algorithms, we fit the spectra and determined the confidence threshold of a given percentage to search for real oscillations. We built two CNN models to obtain the same results as with the MCMC approach.<i>Results<i/>. We applied the CNN models to some observations reported in the literature to prove its reliability in detecting the same events as the classical methods. A day with events that were not previously reported was studied to determine the model capabilities beyond a controlled dataset that we can check with previous reports.<i>Conclusions<i/>. CNNs prove to be a useful tool for studying solar filament oscillations using spectral techniques. The computing times are significantly reduced for results that are similar enough to the classical methods. This is a relevant step toward the automatic detection of filament oscillations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435732","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 : 2025-02-18DOI: 10.1051/0004-6361/202453201
Mauro D’Onofrio, Cesare Chiosi, Francesco Brevi
Context. In the context of the hierarchical formation of galaxies, we investigated the role played by mergers in shaping the scaling relations of galaxies, that is the projections of their fundamental plane onto the Ie − Re, Ie − σ, Re − Ms, and L − σ planes. To this end, based on the scalar virial theorem, we developed a simple theory of multiple dry mergers to read both the large-scale simulations and the companion scaling relations.Aims. The aim was to compare the results of this approach with the observational data and with two of the most recent and detailed numerical cosmo-hydro-dynamical simulations: Illustris-TNG and EAGLE (Evolution and Assembly of GaLaxies and their Environments).Methods. We derived these scaling relations for the galaxies of the Mapping Nearby Galaxies at APO (MaNGA) and Wide-field Imaging of Nearby Galaxy-Clusters Survey (WINGS) databases and compared them with the observational data, the numerical simulations, and the results of our simple theory of dry mergers.Results. The multiple dry merging mechanism is able to explain all the main characteristics of the observed scaling relations of galaxies, such as slopes, scatters, curvatures, and zones of exclusion. The distribution of galaxies in these planes is continuously changing across time because of the merging activity and other physical processes, such as star formation, quenching, and energy feedback.Conclusions. The simple merger theory presented here yields the correct distribution of galaxies in the main scaling relations at all cosmic epochs. The precision is comparable with that obtained by the modern cosmo-hydro-dynamical simulations, with the advantage of providing a rapid exploratory response on the consequences engendered by different physical effects.
背景。在星系分层形成的背景下，我们研究了星系合并在塑造星系缩放关系（即星系基本面在Ie-Re、Ie-σ、Re-Ms和L-σ平面上的投影）中所起的作用。为此，我们以标量维拉定理为基础，建立了一个简单的多干合并理论，以解读大尺度模拟和伴生缩放关系。我们的目的是将这一方法的结果与观测数据以及两个最新、最详细的宇宙水动力数值模拟结果进行比较：方法。我们针对Mapping Nearby Galaxies at APO（MaNGA）和Wide-field Imaging of Nearby Galaxy-Clusters Survey（WINGS）数据库中的星系推导出了这些比例关系，并将它们与观测数据、数值模拟以及我们简单的干合并理论结果进行了比较。多重干合并机制能够解释观测到的星系缩放关系的所有主要特征，如斜率、散射、曲率和排斥区。由于合并活动和其他物理过程，如恒星形成、淬火和能量反馈，这些平面上的星系分布会随着时间的推移而不断变化。本文提出的简单合并理论得出了所有宇宙纪元中星系在主要比例关系中的正确分布。其精确度可与现代宇宙流体动力学模拟相媲美，其优点是可以快速探索不同物理效应产生的后果。
{"title":"The role of dry mergers in shaping the scaling relations of galaxies","authors":"Mauro D’Onofrio, Cesare Chiosi, Francesco Brevi","doi":"10.1051/0004-6361/202453201","DOIUrl":"https://doi.org/10.1051/0004-6361/202453201","url":null,"abstract":"<i>Context.<i/> In the context of the hierarchical formation of galaxies, we investigated the role played by mergers in shaping the scaling relations of galaxies, that is the projections of their fundamental plane onto the <i>I<i/><sub><i>e<i/><sub/> − <i>R<i/><sub><i>e<i/><sub/>, <i>I<i/><sub><i>e<i/><sub/> − <i>σ<i/>, <i>R<i/><sub><i>e<i/><sub/> − <i>M<i/><sub><i>s<i/><sub/>, and <i>L<i/> − <i>σ<i/> planes. To this end, based on the scalar virial theorem, we developed a simple theory of multiple dry mergers to read both the large-scale simulations and the companion scaling relations.<i>Aims.<i/> The aim was to compare the results of this approach with the observational data and with two of the most recent and detailed numerical cosmo-hydro-dynamical simulations: Illustris-TNG and EAGLE (Evolution and Assembly of GaLaxies and their Environments).<i>Methods.<i/> We derived these scaling relations for the galaxies of the Mapping Nearby Galaxies at APO (MaNGA) and Wide-field Imaging of Nearby Galaxy-Clusters Survey (WINGS) databases and compared them with the observational data, the numerical simulations, and the results of our simple theory of dry mergers.<i>Results.<i/> The multiple dry merging mechanism is able to explain all the main characteristics of the observed scaling relations of galaxies, such as slopes, scatters, curvatures, and zones of exclusion. The distribution of galaxies in these planes is continuously changing across time because of the merging activity and other physical processes, such as star formation, quenching, and energy feedback.<i>Conclusions.<i/> The simple merger theory presented here yields the correct distribution of galaxies in the main scaling relations at all cosmic epochs. The precision is comparable with that obtained by the modern cosmo-hydro-dynamical simulations, with the advantage of providing a rapid exploratory response on the consequences engendered by different physical effects.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"34 3 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435739","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 : 2025-02-18DOI: 10.1051/0004-6361/202450142
J. Roy-Perez, S. Pérez-Hoyos, N. Barrado-Izagirre, H. Chen-Chen
Context. Aerosols are capable of having a huge influence on reflected, emitted, and transmitted planetary spectra, especially at wavelengths similar to their average sizes, but also extending to much longer and shorter wavelengths. The Near InfraRed Spectrograph (NIRSpec) using the PRISM mode on board the James Webb Space Telescope (JWST) is providing valuable data of transit spectra over a wide spectral range that is able to cover the whole contribution of aerosols, potentially disentangling them from other constituents, and thus allowing us to constrain their properties.Aims. Our aim was to investigate whether NIRSpec/PRISM JWST transmission spectroscopy observations, in addition to being useful for detecting and determining the abundance of gases more accurately than any previous instruments, are also capable of studying the physical properties of the aerosols in exoplanetary atmospheres.Methods. We performed nested sampling Bayesian retrievals with the MultiNest library. We used the Planetary Spectrum Generator (PSG) and the Modelled Optical Properties of enSeMbles of Aerosol Particles (MOPSMAP) database as tools for the forward simulations and previously published NIRSpec/PRISM JWST observations of WASP-39b as input data.Results. Retrievals indicate that models including an aerosol extinction weakly increasing or sharply decreasing with wavelength are decisively better than those with a flat transmission and that this increased degree of complexity is supported by the kind of data that JWST/NIRSpec can provide. Given other physical constraints from previous works, the scenario of weakly increasing particle extinction is favoured. We find that this also has an effect on the retrieved gas abundances.Conclusions. JWST observations give us the potential to study some physical characteristics of exoplanetary clouds, in particular their overall dependence of transmissivity on wavelength. It is important to implement more detailed aerosol models as their extinction may affect significantly retrieved molecular abundances.
{"title":"The role of cloud particle properties in the WASP-39b transmission spectrum based on JWST/NIRSpec observations","authors":"J. Roy-Perez, S. Pérez-Hoyos, N. Barrado-Izagirre, H. Chen-Chen","doi":"10.1051/0004-6361/202450142","DOIUrl":"https://doi.org/10.1051/0004-6361/202450142","url":null,"abstract":"<i>Context<i/>. Aerosols are capable of having a huge influence on reflected, emitted, and transmitted planetary spectra, especially at wavelengths similar to their average sizes, but also extending to much longer and shorter wavelengths. The Near InfraRed Spectrograph (NIRSpec) using the PRISM mode on board the <i>James Webb<i/> Space Telescope (JWST) is providing valuable data of transit spectra over a wide spectral range that is able to cover the whole contribution of aerosols, potentially disentangling them from other constituents, and thus allowing us to constrain their properties.<i>Aims<i/>. Our aim was to investigate whether NIRSpec/PRISM JWST transmission spectroscopy observations, in addition to being useful for detecting and determining the abundance of gases more accurately than any previous instruments, are also capable of studying the physical properties of the aerosols in exoplanetary atmospheres.<i>Methods<i/>. We performed nested sampling Bayesian retrievals with the MultiNest library. We used the Planetary Spectrum Generator (PSG) and the Modelled Optical Properties of enSeMbles of Aerosol Particles (MOPSMAP) database as tools for the forward simulations and previously published NIRSpec/PRISM JWST observations of WASP-39b as input data.<i>Results<i/>. Retrievals indicate that models including an aerosol extinction weakly increasing or sharply decreasing with wavelength are decisively better than those with a flat transmission and that this increased degree of complexity is supported by the kind of data that JWST/NIRSpec can provide. Given other physical constraints from previous works, the scenario of weakly increasing particle extinction is favoured. We find that this also has an effect on the retrieved gas abundances.<i>Conclusions<i/>. JWST observations give us the potential to study some physical characteristics of exoplanetary clouds, in particular their overall dependence of transmissivity on wavelength. It is important to implement more detailed aerosol models as their extinction may affect significantly retrieved molecular abundances.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"11 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435731","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 : 2025-02-18DOI: 10.1051/0004-6361/202453474
Irham T. Andika, Stefan Schuldt, Sherry H. Suyu, Satadru Bag, Raoul Cañameras, Alejandra Melo, Claudio Grillo, James H. H. Chan
Strongly lensed quasars provide valuable insights into the rate of cosmic expansion, the distribution of dark matter in foreground deflectors, and the characteristics of quasar hosts. However, detecting them in astronomical images is difficult due to the prevalence of non-lensing objects. To address this challenge, we developed a generative deep learning model called VariLens, built upon a physics-informed variational autoencoder. This model seamlessly integrates three essential modules: image reconstruction, object classification, and lens modeling, offering a fast and comprehensive approach to strong lens analysis. VariLens is capable of rapidly determining both (1) the probability that an object is a lens system and (2) key parameters of a singular isothermal ellipsoid (SIE) mass model – including the Einstein radius (θE), lens center, and ellipticity – in just milliseconds using a single CPU. A direct comparison of VariLens estimates with traditional lens modeling for 20 known lensed quasars within the Subaru Hyper Suprime-Cam (HSC) footprint shows good agreement, with both results consistent within 2σ for systems with θE < 3″. To identify new lensed quasar candidates, we began with an initial sample of approximately 80 million sources, combining HSC data with multiwavelength information from Gaia, UKIRT, VISTA, WISE, eROSITA, and VLA. After applying a photometric preselection aimed at locating z > 1.5 sources, the number of candidates was reduced to 710 966. Subsequently, VariLens highlights 13 831 sources, each showing a high likelihood of being a lens. A visual assessment of these objects results in 42 promising candidates that await spectroscopic confirmation. These results underscore the potential of automated deep learning pipelines to efficiently detect and model strong lenses in large datasets, substantially reducing the need for manual inspection.
{"title":"Accelerating lensed quasar discovery and modeling with physics-informed variational autoencoders","authors":"Irham T. Andika, Stefan Schuldt, Sherry H. Suyu, Satadru Bag, Raoul Cañameras, Alejandra Melo, Claudio Grillo, James H. H. Chan","doi":"10.1051/0004-6361/202453474","DOIUrl":"https://doi.org/10.1051/0004-6361/202453474","url":null,"abstract":"Strongly lensed quasars provide valuable insights into the rate of cosmic expansion, the distribution of dark matter in foreground deflectors, and the characteristics of quasar hosts. However, detecting them in astronomical images is difficult due to the prevalence of non-lensing objects. To address this challenge, we developed a generative deep learning model called VariLens, built upon a physics-informed variational autoencoder. This model seamlessly integrates three essential modules: image reconstruction, object classification, and lens modeling, offering a fast and comprehensive approach to strong lens analysis. VariLens is capable of rapidly determining both (1) the probability that an object is a lens system and (2) key parameters of a singular isothermal ellipsoid (SIE) mass model – including the Einstein radius (<i>θ<i/><sub>E<sub/>), lens center, and ellipticity – in just milliseconds using a single CPU. A direct comparison of VariLens estimates with traditional lens modeling for 20 known lensed quasars within the Subaru Hyper Suprime-Cam (HSC) footprint shows good agreement, with both results consistent within 2<i>σ<i/> for systems with <i>θ<i/><sub>E<sub/> < 3″. To identify new lensed quasar candidates, we began with an initial sample of approximately 80 million sources, combining HSC data with multiwavelength information from Gaia, UKIRT, VISTA, WISE, eROSITA, and VLA. After applying a photometric preselection aimed at locating <i>z<i/> > 1.5 sources, the number of candidates was reduced to 710 966. Subsequently, VariLens highlights 13 831 sources, each showing a high likelihood of being a lens. A visual assessment of these objects results in 42 promising candidates that await spectroscopic confirmation. These results underscore the potential of automated deep learning pipelines to efficiently detect and model strong lenses in large datasets, substantially reducing the need for manual inspection.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"29 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435733","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 : 2025-02-18DOI: 10.1051/0004-6361/202451448
Malte Brinch, Shuowen Jin, Raphael Gobat, Nikolaj B. Sillassen, Hiddo Algera, Steven Gillman, Thomas R. Greve, Carlos Gomez-Guijarro, Bitten Gullberg, Jacqueline Hodge, Minju Lee, Daizhong Liu, Georgios Magdis, Francesco Valentino
We present the confirmation of a compact galaxy group candidate, CGG-z4, at z = 4.3 in the COSMOS field. This structure was identified by two spectroscopically confirmed z = 4.3 Ks-dropout galaxies with ALMA 870 μm and 3 mm continuum detections, surrounded by an overdensity of near infrared-detected galaxies with consistent photometric redshifts of 4.0 < z < 4.6. The two ALMA sources, CGG-z4.a and CGG-z4.b, have been detected with both CO(4–3) and CO(5–4) lines, whereby [CI](1–0) has been detected on CGG-z4.a, and H2O(11, 0–10, 1) absorption detected on CGG-z4.b. We modeled an integrated spectral energy distribution (SED) by combining the far-infrared-to-radio photometry of this group and estimated a total star formation rate of ∼2000 M⊙ yr−1, making it one of the most star-forming groups known at z > 4. Their high CO(5–4)/CO(4–3) ratios indicate that each respective interstellar medium (ISM) is close to thermalization, suggesting either high gas temperatures, high densities, and/or high pressure; whereas the low [CI](1–0)/CO(4–3) line ratios indicate high star formation efficiencies. With the [CI]-derived gas masses, we found the two galaxies have extremely short gas depletion times of 99 Myr and < 63 Myr, respectively, suggesting the onset of quenching. With an estimated halo mass of log(Mhalo [M⊙]) ∼ 12.8, we find that this structure is likely to be in the process of forming a massive galaxy cluster.
{"title":"Revealing the hidden cosmic feast: A z = 4.3 galaxy group hosting two optically dark, efficiently star-forming galaxies","authors":"Malte Brinch, Shuowen Jin, Raphael Gobat, Nikolaj B. Sillassen, Hiddo Algera, Steven Gillman, Thomas R. Greve, Carlos Gomez-Guijarro, Bitten Gullberg, Jacqueline Hodge, Minju Lee, Daizhong Liu, Georgios Magdis, Francesco Valentino","doi":"10.1051/0004-6361/202451448","DOIUrl":"https://doi.org/10.1051/0004-6361/202451448","url":null,"abstract":"We present the confirmation of a compact galaxy group candidate, CGG-z4, at <i>z<i/> = 4.3 in the COSMOS field. This structure was identified by two spectroscopically confirmed <i>z<i/> = 4.3 <i>K<i/><sub><i>s<i/><sub/>-dropout galaxies with ALMA 870 μm and 3 mm continuum detections, surrounded by an overdensity of near infrared-detected galaxies with consistent photometric redshifts of 4.0 < <i>z<i/> < 4.6. The two ALMA sources, CGG-z4.a and CGG-z4.b, have been detected with both CO(4–3) and CO(5–4) lines, whereby [CI](1–0) has been detected on CGG-z4.a, and H<sub>2<sub/>O(1<sub>1, 0<sub/>–1<sub>0, 1<sub/>) absorption detected on CGG-z4.b. We modeled an integrated spectral energy distribution (SED) by combining the far-infrared-to-radio photometry of this group and estimated a total star formation rate of ∼2000 M<sub>⊙<sub/> yr<sup>−1<sup/>, making it one of the most star-forming groups known at <i>z<i/> > 4. Their high CO(5–4)/CO(4–3) ratios indicate that each respective interstellar medium (ISM) is close to thermalization, suggesting either high gas temperatures, high densities, and/or high pressure; whereas the low [CI](1–0)/CO(4–3) line ratios indicate high star formation efficiencies. With the [CI]-derived gas masses, we found the two galaxies have extremely short gas depletion times of 99 Myr and < 63 Myr, respectively, suggesting the onset of quenching. With an estimated halo mass of log(M<sub>halo<sub/> [M<sub>⊙<sub/>]) ∼ 12.8, we find that this structure is likely to be in the process of forming a massive galaxy cluster.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"68 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435773","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 : 2025-02-18DOI: 10.1051/0004-6361/202452224
Ezequiel Centofanti, Samuel Farrens, Jean-Luc Starck, Tobías Liaudat, Alex Szapiro, Jennifer Pollack
The spectral energy distribution (SED) of observed stars in wide-field images is crucial for chromatic point spread function (PSF) modelling methods, which use unresolved stars as integrated spectral samples of the PSF across the field of view. This is particularly important for weak gravitational lensing studies, where precise PSF modelling is essential to get accurate shear measurements. Previous research has demonstrated that the SED of stars can be inferred from low-resolution observations using machine-learning classification algorithms. However, a degeneracy exists between the PSF size, which can vary significantly across the field of view, and the spectral type of stars, leading to strong limitations of such methods. We propose a new SED classification method that incorporates stellar spectral information by using a preliminary PSF model, thereby breaking this degeneracy and enhancing the classification accuracy. Our method involves calculating a set of similarity features between an observed star and a preliminary PSF model at different wavelengths and applying a support vector machine to these similarity features to classify the observed star into a specific stellar class. The proposed approach achieves a 91% top-two accuracy, surpassing machine-learning methods that do not consider the spectral variation of the PSF. Additionally, we examined the impact of PSF modelling errors on the spectral classification accuracy.
{"title":"Breaking the degeneracy in stellar spectral classification from single wide-band images","authors":"Ezequiel Centofanti, Samuel Farrens, Jean-Luc Starck, Tobías Liaudat, Alex Szapiro, Jennifer Pollack","doi":"10.1051/0004-6361/202452224","DOIUrl":"https://doi.org/10.1051/0004-6361/202452224","url":null,"abstract":"The spectral energy distribution (SED) of observed stars in wide-field images is crucial for chromatic point spread function (PSF) modelling methods, which use unresolved stars as integrated spectral samples of the PSF across the field of view. This is particularly important for weak gravitational lensing studies, where precise PSF modelling is essential to get accurate shear measurements. Previous research has demonstrated that the SED of stars can be inferred from low-resolution observations using machine-learning classification algorithms. However, a degeneracy exists between the PSF size, which can vary significantly across the field of view, and the spectral type of stars, leading to strong limitations of such methods. We propose a new SED classification method that incorporates stellar spectral information by using a preliminary PSF model, thereby breaking this degeneracy and enhancing the classification accuracy. Our method involves calculating a set of similarity features between an observed star and a preliminary PSF model at different wavelengths and applying a support vector machine to these similarity features to classify the observed star into a specific stellar class. The proposed approach achieves a 91% top-two accuracy, surpassing machine-learning methods that do not consider the spectral variation of the PSF. Additionally, we examined the impact of PSF modelling errors on the spectral classification accuracy.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435740","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 : 2025-02-18DOI: 10.1051/0004-6361/202453051
Huanchen Hu, Nataliya K. Porayko, Willem van Straten, Michael Kramer, David J. Champion, Michael J. Keith
Common signal-processing approximations produce artefacts when timing pulsars in relativistic binary systems, especially edge-on systems with tight orbits, such as the Double Pulsar. In this paper, we use extensive simulations to explore various patterns that arise from the inaccuracies of approximations made when correcting dispersion and Shapiro delay. In a relativistic binary, the velocity of the pulsar projected onto the line of sight varies significantly on short timescales, causing rapid changes in the apparent pulsar spin frequency, which is used to convert dispersive delays to pulsar rotational phase shifts. A well-known example of the consequences of this effect is the artificial variation of dispersion measure (DM) with binary phase, first observed in the Double Pulsar 20 years ago. We show that ignoring the Doppler shift of the spin frequency when computing the dispersive phase shift exactly reproduces the shape and magnitude of the reported DM variations. We also simulate and study two additional effects of much smaller magnitude, which are caused by the assumption that the spin frequency used to correct dispersion is constant over the duration of the sub-integration and over the observed bandwidth. We show that failure to account for these two effects leads to orbital phase-dependent dispersive smearing that leads to apparent orbital DM variations. The functional form of the variation depends on the orbital eccentricity. In addition, we find that a polynomial approximation of the timing model is unable to accurately describe the Shapiro delay of edge-on systems with orbits of less than four hours, which poses problems for the measurements of timing parameters, most notably the Shapiro delay. This will be a potential issue for sensitive facilities such as the Five-hundred-meter Aperture Spherical Telescope (FAST) and the forthcoming Square Kilometre Array (SKA); therefore, a more accurate phase predictor is indispensable.
{"title":"Tackling artefacts in the timing of relativistic pulsar binaries: Towards the SKA","authors":"Huanchen Hu, Nataliya K. Porayko, Willem van Straten, Michael Kramer, David J. Champion, Michael J. Keith","doi":"10.1051/0004-6361/202453051","DOIUrl":"https://doi.org/10.1051/0004-6361/202453051","url":null,"abstract":"Common signal-processing approximations produce artefacts when timing pulsars in relativistic binary systems, especially edge-on systems with tight orbits, such as the Double Pulsar. In this paper, we use extensive simulations to explore various patterns that arise from the inaccuracies of approximations made when correcting dispersion and Shapiro delay. In a relativistic binary, the velocity of the pulsar projected onto the line of sight varies significantly on short timescales, causing rapid changes in the apparent pulsar spin frequency, which is used to convert dispersive delays to pulsar rotational phase shifts. A well-known example of the consequences of this effect is the artificial variation of dispersion measure (DM) with binary phase, first observed in the Double Pulsar 20 years ago. We show that ignoring the Doppler shift of the spin frequency when computing the dispersive phase shift exactly reproduces the shape and magnitude of the reported DM variations. We also simulate and study two additional effects of much smaller magnitude, which are caused by the assumption that the spin frequency used to correct dispersion is constant over the duration of the sub-integration and over the observed bandwidth. We show that failure to account for these two effects leads to orbital phase-dependent dispersive smearing that leads to apparent orbital DM variations. The functional form of the variation depends on the orbital eccentricity. In addition, we find that a polynomial approximation of the timing model is unable to accurately describe the Shapiro delay of edge-on systems with orbits of less than four hours, which poses problems for the measurements of timing parameters, most notably the Shapiro delay. This will be a potential issue for sensitive facilities such as the Five-hundred-meter Aperture Spherical Telescope (FAST) and the forthcoming Square Kilometre Array (SKA); therefore, a more accurate phase predictor is indispensable.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"80 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435712","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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