Astronomy & Astrophysics最新文献

{"title":"Temporal evolution of the third interstellar comet 3I/ATLAS: Spin, color, spectra, and dust activity⋆","authors":"T. Santana-Ros, O. Ivanova, S. Mykhailova, N. Erasmus, K. Kamiński, D. Oszkiewicz, T. Kwiatkowski, M. Husárik, T. S. Ngwane, A. Penttilä","doi":"10.1051/0004-6361/202556717","DOIUrl":"https://doi.org/10.1051/0004-6361/202556717","url":null,"abstract":"<i>Aims.<i/> We aim to characterize the physical and activity properties of the interstellar comet 3I/ATLAS through spectroscopic and photometric observations during the first month after its discovery.<i>Methods.<i/> We performed time series photometry and long-slit spectroscopy between 2 and 29 July 2025 using multiple ground-based telescopes. Photometric data were calibrated against field stars from the ATLAS and APASS catalogs, and Fourier analysis was applied to derive the comet’s rotational period. Spectral data were obtained using the Southern African Large Telescope and the Nordic Optical Telescope.<i>Results.<i/> We report a spin period of 16.16 ± 0.01 h with a light curve amplitude of approximately 0.3 mag. The comet exhibits increasing dust activity and reddening colors during the observation period with no visible tail detected, likely due to viewing geometry and low dust production. Dust mass-loss rates are estimated between 0.3 and 4.2 kg s<sup>−1<sup/>, consistent with weakly active distant comets. Spectral colors are similar to those of outer Solar System comets and differ from previously reported values for 3I/ATLAS.<i>Conclusions.<i/> The morphological and photometric properties of 3I/ATLAS are consistent with a weakly active comet of outer Solar System origin despite its interstellar provenance. Continued monitoring around perihelion is necessary to track changes in activity and color, which will provide insights into the evolution of interstellar materials under solar radiation.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"118 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182820","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}

{"title":"Direct measurement of ISM proper motion with image registration","authors":"M. Piecka, L. Posch, S. Meingast, S. Hutschenreuter, A. Rottensteiner, J. Alves","doi":"10.1051/0004-6361/202556622","DOIUrl":"https://doi.org/10.1051/0004-6361/202556622","url":null,"abstract":"To date, the quantification of the on-sky motion for interstellar clouds has relied on proxies such as young stellar objects (YSOs) and masers. We present the first direct measurement of an interstellar cloud proper motion using the VISTA Star Formation Atlas (VISIONS) multi-epoch infrared images of the Corona Australis star-forming region. Proper motions are extracted by tracking the morphology of extended structures in the cloud complex based on image registration techniques implemented in SimpleITK. Our determined values (<i>μ<i/><sub><i>α<i/><sup>*<sup/><sub/> ∼ +15 mas yr<sup>−1<sup/>, <i>μ<i/><sub><i>δ<i/><sub/> ∼ −30 mas yr<sup>−1<sup/>) are in good agreement with those obtained for YSOs and young stellar clusters in the region. This study demonstrates the potential of image registration for directly mapping the kinematics of nearby molecular clouds, opening a new window into the study of cloud dynamics.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"95 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182821","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}

{"title":"Late accretion offers pathway to misaligned disk around the planet-hosting IRAS 04125+2902","authors":"L.-A. Hühn, H.-C. Jiang, C. P. Dullemond","doi":"10.1051/0004-6361/202555391","DOIUrl":"https://doi.org/10.1051/0004-6361/202555391","url":null,"abstract":"We present a 3D hydrodynamical simulation of the accretion of a gas cloudlet onto the IRAS 04125+2902 binary system, where the 3-Myr-old primary hosts a transiting planet. We demonstrate that such an accretion event can naturally produce a circumstellar disk that is misaligned with respect to the rest of the system, consistent with the observed misaligned transition disk. In the model, the prescribed orbital plane of the cloudlet is largely retained by the resulting circumstellar disk after undergoing gravitational interactions with the secondary during the initial accretion. After ∼4.4 binary orbits, a disk with <i>R<i/><sub>d<sub/> = 300 AU has formed around the stellar primary made of ∼13% of the cloudlet mass, <i>M<i/><sub>d,p<sub/> = 2.1 × 10<sup>−3<sup/> M<sub>⊙<sub/>. The companion also retains some of the cloudlet’s mass and forms a disk with <i>M<i/><sub>d,c<sub/> = 9.3 × 10<sup>−5<sup/> M<sub>⊙<sub/>, though only the transition disk around the primary has been observed. Our findings highlight the importance of considering mass inflow onto a protoplanetary disk for its evolution.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"106 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182853","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}

{"title":"He II emitters at cosmic noon and beyond","authors":"R. González-Díaz, J. M. Vílchez, C. Kehrig, I. del Moral-Castro, J. Iglesias-Páramo","doi":"10.1051/0004-6361/202555935","DOIUrl":"https://doi.org/10.1051/0004-6361/202555935","url":null,"abstract":"The study of high-redshift galaxies provides critical insights into the early stages of cosmic evolution, particularly during what is known as cosmic noon, when star formation activity reached its peak. Within this context, the origin of the nebular He II emission remains an open question. For this work, we conducted a systematic multi-wavelength investigation of a sample of <i>z<i/> ∼ 2–4 He II <i>λ<i/>1640 Å emitters from the MUSE Hubble Ultra Deep Field surveys, utilising both MUSE and JWST/NIRSpec data and extending the sample presented by previous studies. We derived gas-phase metallicities and key physical properties, including electron densities, temperatures, and the production rates of hydrogen- and He<sup>+<sup/>-ionising photons. Our results suggest that a combination of factors, such as stellar mass, initial mass function, stellar metallicity, and stellar multiplicity, likely contributes to the origin of the observed nebular He II emission. Specifically, for our galaxies with higher gas-phase metallicity (12 + log(O/H) ≳ 7.55), we find that models for binary population with Salpeter IMF (<i>M<i/><sub>up<sub/> = 100 M<sub>⊙<sub/>) and stellar metallicity <i>Z<i/><sub>⋆<sub/> ≈ 10<sup>−3<sup/> (i.e. similar to that of the gas) can reproduce the observed He II ionising conditions. However, at lower metallicities, models for binary populations with a ‘top-heavy’ initial mass function (<i>M<i/><sub>up<sub/> = 300 M<sub>⊙<sub/>) and <i>Z<i/><sub>⋆<sub/> much lower than that of the gas (10<sup>−4<sup/> < <i>Z<i/><sub>⋆<sub/> < 10<sup>−5<sup/>) are required to fully account for the observed He II ionising photon production. These results reinforce that the He II ionisation keeps challenging current stellar populations, and the He II ionisation problem persists in the very low-metallicity regime.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"226 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182855","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}

{"title":"Monte Carlo simulations of magnetospheric ion precipitation into Triton's upper atmosphere: Sputtering, energy deposition, charge exchange, and ionization","authors":"Xu Huang, Hao Gu, Jun Cui","doi":"10.1051/0004-6361/202556273","DOIUrl":"https://doi.org/10.1051/0004-6361/202556273","url":null,"abstract":"<i>Context<i/>. Magnetospheric ion precipitation is an important driver of energy and mass transfer in a planet’s upper atmosphere. When energetic ions penetrate an atmosphere, they undergo a cascade of interactions with background species, including elastic scattering, charge exchange, excitation, dissociation, and ionization. These processes can alter the atmospheric composition and potentially contribute to atmospheric escape, a process known as sputtering.<i>Aims<i/>. We investigated the effects of magnetospheric N<sup>+<sup/> and H<sup>+<sup/> precipitation on Triton’s upper atmosphere.<i>Methods<i/>. We established a one-dimensional test particle Monte Carlo model to simulate the process.<i>Results<i/>. Our simulations indicate a total nitrogen escape rate of approximately (0.2-2)× 10<sup>26<sup/> s<sup>−1<sup/>, primarily resulting from incident N<sup>+<sup/> ions. This rate is comparable to the previously reported values for Jeans escape and chemical escape, indicating that ion precipitation is a substantial contributor to Triton’s atmospheric loss. We also quantified the energy deposition, charge exchange, and ionization rates along with the energy degradation of incident ions, and assessed their sensitivities to ion energy, incidence angle, and scattering angle distribution.<i>Conclusions<i/>. While magnetospheric electron precipitation likely dominates atmospheric ionization on Triton, our estimations suggest that the contribution of ion precipitation is non-negligible.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"31 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182830","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}

{"title":"Forming deuterated methanol in pre-stellar core conditions","authors":"W. Riedel, O. Sipilä, E. Redaelli, M. Jin, A. I. Vasyunin, R. T. Garrod, P. Caselli","doi":"10.1051/0004-6361/202554835","DOIUrl":"https://doi.org/10.1051/0004-6361/202554835","url":null,"abstract":"<i>Context<i/>. The formation mechanisms for most complex organic molecules (COMs) are still debated. Either COMs form mostly on the surface of dust grains or mostly by reactions between simpler hydrogenation products upon their desorption into the gas phase. Methanol, the simplest of the O-bearing COMs, plays a key role in both scenarios.<i>Aims<i/>. Our aim is to improve the suitability of our models for the formation and deuteration of COMs in the extremely cold conditions of pre-stellar cores, where chemical reactions between heavier reactants on the surface of dust grains are hindered by the reactant’s immobility. Initially, we focused our efforts on CH<sub>3<sub/>OH and its singly deuterated isotopologue CH<sub>2<sub/>DOH.<i>Methods<i/>. We updated a gas-grain chemical code capable of deuterium chemistry by including various non-diffusive reaction mechanisms: Eley–Rideal reactions, photodissociation-induced reactions, and three-body reactions. Moreover, we added the reaction H<sub>2<sub/>CO + CH<sub>3<sub/>O → CH<sub>3<sub/>OH + HCO to our chemical network, which was found to contribute significantly to methanol formation in both microscopic kinetic Monte Carlo simulations and laboratory experiments. We performed several 1D simulations of the pre-stellar core L1544, where we derived column density profiles for CH<sub>3<sub/>OH and CH<sub>2<sub/>DOH and compared our model results with more conventional modelling approaches and available gas-phase observations.<i>Results<i/>. We show that multiple models with different parameter sets provide column density profiles that are in reasonable agreement with the observed values. On the one hand, when applying a single collision reaction probability, either an increase in the reaction rate by the occurrence of diffusion by quantum tunneling or a lowered diffusion-to-binding energy ratio (<i>E<i/><sub>d<sub/>/<i>E<i/><sub>b<sub/> = 0.2) for thermal diffusion is needed to match the observed methanol levels. On the other hand, when applying reaction-diffusion competition, reactions proceeding by thermal diffusion with a conservative diffusion-to-binding energy ratio (<i>E<i/><sub>d<sub/>/<i>E<i/><sub>b<sub/> = 0.55) are sufficient to reach observed column densities. We find that, in contrast to other COMs, the introduced non-diffusive mechanisms play only a secondary role in the formation and deuteration of methanol. Additionally, we find only a negligible contribution from H<sub>2<sub/>CO + CH<sub>3<sub/>O → CH<sub>3<sub/>OH + HCO.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"6 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182881","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}

{"title":"Fuelling, evolution, and diversity of active galactic nuclei in dwarf galaxies: Insights from star formation and black hole scaling relations","authors":"G. Mountrichas, M. Siudek, F. J. Carrera","doi":"10.1051/0004-6361/202555697","DOIUrl":"https://doi.org/10.1051/0004-6361/202555697","url":null,"abstract":"We investigated the star formation activity and black hole scaling relations in a sample of 1 451 active galactic nuclei (AGNs) hosted by dwarf galaxies (log(<i>M<i/><sub>⋆<sub/>/<i>M<i/><sub>⊙<sub/>) < 10) at 0.5 < <i>z<i/> < 0.9, drawn from the VIPERS survey. The sample comprises Seyferts and low-ionization nuclear emission-line regions (LINERs) identified through emission-line diagnostics, as well as IR-selected AGNs based on WISE mid-IR colours. Using the normalized star formation rate (SFR<sub>norm<sub/>), defined as the ratio of the SFR of a galaxy hosting an AGN to the median SFR of star-forming galaxies of similar stellar masses and redshifts, we compared AGN hosts to a control sample of non-AGN star-forming galaxies. We examined how SFR<sub>norm<sub/> varies with AGN power (<i>L<i/>[OIII]), black hole mass (<i>M<i/><sub>BH<sub/>), local environment, and stellar population age. We also analysed the <i>M<i/><sub>BH<sub/>–<i>M<i/><sub>⋆<sub/> relation and the evolution of the <i>M<i/><sub>BH<sub/>/<i>M<i/><sub>⋆<sub/> ratio, incorporating comparisons to X-ray AGNs and high-redshift quasars (<i>z<i/> > 4). We note that black hole masses have been estimated from narrow-line diagnostics, which introduce significant scatter and can carry substantial uncertainties for individual sources, though they remain useful for identifying statistical trends. Our key findings are: (i) All AGN populations show suppressed star formation at low AGN luminosities, with SFR<sub>norm<sub/> rising above unity at different luminosity thresholds depending on AGN type. (ii) LINERs show flat SFR<sub>norm<sub/> trends with <i>M<i/><sub>BH<sub/>, remaining broadly consistent with unity. Seyferts display a mild increase with <i>M<i/><sub>BH<sub/>, while IR AGNs show a more pronounced positive trend. (iii) LINERs have older stellar populations than Seyferts. (iv) At fixed stellar mass, Seyferts host more massive black holes than LINERs, with IR AGNs falling in between. (v) The <i>M<i/><sub>BH<sub/>/<i>M<i/><sub>⋆<sub/> ratio is elevated relative to local scaling relations and remains approximately constant with redshift over 0.5 < <i>z<i/> < 0.9, in agreement with high-<i>z<i/> AGN measurements. (vi) The ratio decreases with stellar mass up to log(<i>M<i/><sub>⋆<sub/>/<i>M<i/><sub>⊙<sub/>)∼11, beyond which it flattens towards values consistent with those of local, inactive galaxies; this trend is clearest for Seyferts and IR AGNs, while LINERs show no clear dependence. These results suggest that AGNs in dwarf galaxies follow diverse evolutionary pathways, shaped by gas availability, feedback, and selection effects.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182822","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}

{"title":"Notes on the formaldehyde masers","authors":"D. J. van der Walt","doi":"10.1051/0004-6361/202556038","DOIUrl":"https://doi.org/10.1051/0004-6361/202556038","url":null,"abstract":"&lt;i&gt;Context.&lt;i/&gt; The 4.8 GHz formaldehyde masers are rare when compared, for example, to the class II methanol masers, especially when both masers are associated with high-mass star-forming regions. Apart from the rarity of the masers, which has not yet been explained, the non-detection of associated 14.5 GHz masers is also still an outstanding question.&lt;i&gt;Aims.&lt;i/&gt; The first aim of the present work is to investigate, from a theoretical point of view and with more realistic free-free spectral energy distributions (SEDs), whether there are physical conditions in the molecular envelope under which the 1&lt;sub&gt;10&lt;sub/&gt;–1&lt;sub&gt;11&lt;sub/&gt; transition is inverted but not the 2&lt;sub&gt;11&lt;sub/&gt;–2&lt;sub&gt;12&lt;sub/&gt; transition. The possibility that the non-detection of 14.5 GHz masers is due to the masing region being projected towards the edge of a background hyper-compact H II region is also investigated. Since the 1&lt;sub&gt;10&lt;sub/&gt;–1&lt;sub&gt;11&lt;sub/&gt; transition of ortho-H&lt;sub&gt;2&lt;sub/&gt;CO is known to have an anti-inversion behaviour for typical conditions associated with high-mass star-forming regions, it is possible that attenuation affects the 4.8 and 14.5 GHz masers. The second aim is to estimate to what extent attenuation of the 4.8 and 14.5 GHz H&lt;sub&gt;2&lt;sub/&gt;CO masers in the molecular envelope can explain the small number of detected H&lt;sub&gt;2&lt;sub/&gt;CO masers.&lt;i&gt;Methods.&lt;i/&gt; The photo-ionisation code Cloudy was used to calculate more realistic free-free SEDs for a given spectral type of the ionising star and different radial dependences of the initial H I distribution. The free-free SED obtained from the Cloudy simulation was used as the pumping radiation field in the statistical equilibrium calculations.&lt;i&gt;Results.&lt;i/&gt; Using a fit from the Cloudy simulations to the observed free-free SED of the hyper-compact H II region G24.78+0.08 A1, it is found that while the 1&lt;sub&gt;10&lt;sub/&gt;–1&lt;sub&gt;11&lt;sub/&gt; transition is weakly inverted, the 2&lt;sub&gt;11&lt;sub/&gt;–2&lt;sub&gt;12&lt;sub/&gt; transition is not inverted. In this case, inversion of the 1&lt;sub&gt;10&lt;sub/&gt;–1&lt;sub&gt;11&lt;sub/&gt; transition is dominated by collisions and the contribution of the free-free radiation field to the inversion is negligible. Analysis of the dependence of the inversion of the 1&lt;sub&gt;10&lt;sub/&gt;–1&lt;sub&gt;11&lt;sub/&gt; and 2&lt;sub&gt;11&lt;sub/&gt;–2&lt;sub&gt;12&lt;sub/&gt; transitions on distance into the molecular cloud suggests that there are regions in the circumstellar envelope where the 1&lt;sub&gt;10&lt;sub/&gt;–1&lt;sub&gt;11&lt;sub/&gt; transition is inverted but not the 2&lt;sub&gt;11&lt;sub/&gt;–2&lt;sub&gt;12&lt;sub/&gt; transition. The optical depths at 4.8 and 14.5 GHz were calculated for three different dependences of the abundance of o-H&lt;sub&gt;2&lt;sub/&gt;CO on depth into the molecular cloud, which shows that significant attenuation of the maser emission is possible.&lt;i&gt;Conclusions.&lt;i/&gt; Not all hyper-compact H II regions have free-free SEDs that are able to produce strong enough 4.8 GHz masers. Attenuation of the 4.8 GHz maser emission in the molecular envelope can be so significant that the 4.8 GHz maser emissi","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"94 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141380","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}

{"title":"An improved algorithm for separating clock delays from ionospheric effects in radio astronomy","authors":"C. M. Cordun, M. A. Brentjens, H. K. Vedantham, M. Mevius","doi":"10.1051/0004-6361/202556263","DOIUrl":"https://doi.org/10.1051/0004-6361/202556263","url":null,"abstract":"<i>Context<i/>. Low-frequency radio observations are heavily impacted by the ionosphere, where dispersive delays can outpace even instrumental clock offsets, posing a serious calibration challenge. Especially below 100 MHz, phase unwrapping difficulties and higher-order dispersion effects can complicate the separation of ionospheric and clock delays.<i>Aims<i/>. We address this challenge by introducing a method for reliably separating clock delays from ionospheric effects, even under mediocre to poor ionospheric conditions encountered near solar maximum.<i>Methods<i/>. The approach employs a key technique: we modelled our likelihood space using the circular Gaussian distribution (von Mises random variable) rather than non-circular distributions that suffer from 2<i>π<i/> phase ambiguities. This ensures that noisier data are weighted less heavily than cleaner data during the fitting process.<i>Results<i/>. The method reliably separates clock delays and ionospheric terms that vary smoothly in time whilst providing a good fit to the data. A comparison with the clock-ionosphere separation approach used in standard LOFAR data processing shows that our technique achieves significant improvements. In contrast to the old algorithm, which often fails to return reliable results below 100 MHz even under good ionospheric conditions, the new algorithm consistently provides reliable solutions across a wider range of conditions.<i>Conclusions<i/>. This new algorithm represents a significant advance for large-scale surveys, offering a more dependable way to study ionospheric effects and furthering research in ionospheric science and low-frequency radio astronomy.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"123 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141379","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}

{"title":"The GAPS Programme at TNG","authors":"G. Guilluy, P. Giacobbe, M. Brogi, F. Borsa, J. P. Wardenier, F. Amadori, P. E. Cubillos, M. Basilicata, A. S. Bonomo, A. Sozzetti, I. Carleo, T. Azevedo Silva, A. Bignamini, M. Damasso, C. Di Maio, A. Ghedina, M. Lodi, L. Mancini, F. Manni, G. Micela, V. Nascimbeni, D. Nardiello, L. Pino, M. Rainer, G. Scandariato","doi":"10.1051/0004-6361/202555702","DOIUrl":"https://doi.org/10.1051/0004-6361/202555702","url":null,"abstract":"<i>Context<i/>. The study of the atmosphere of ultra-hot Jupiters (UHJs) with equilibrium temperatures ≥2000 K provides valuable insights into atmospheric physics under such extreme conditions.<i>Aims<i/>. We aim to characterise the dayside thermal spectrum of the UHJ WASP-76 b and investigate its properties. We analysed data gathered with three high-resolution spectrographs: specifically two nights with simultaneous observations of HARPS-N and GIANO-B, and four nights of publicly available ESPRESSO optical spectra. We observed the planet’s dayside, covering orbital phases between quadratures (0.25 < ϕ < 0.75).<i>Methods<i/>. We performed a homogeneous analysis of the GIANO-B, HARPS-N, and ESPRESSO data and co-added the signal of thousands of planetary lines through cross-correlation with simulated spectra of the planetary atmosphere.<i>Results<i/>. We report the detection of CO in the dayside atmosphere of WASP-76 b with a signal-to-noise ratio (S/N) of 10.4 in the GIANO-B spectra. In addition, we detect Fe I in both the HARPS-N and ESPRESSO datasets, with S/N values of 3.5 and 6.2, respectively. A signal from Fe I is also identified in one of the two GIANO-B observations, with an S/N of 4.0. Interestingly, a qualitatively similar pattern – with a weaker detection in one epoch compared to the other – is also observed in the two HARPS-N nights. The GIANO-B results are, therefore, consistent with those obtained with HARPS-N. Finally, we compared our strongest detections of CO (GIANO-B) and Fe I (ESPRESSO), with predictions from global circulation models (GCM). Both cross-correlation and likelihood analyses favour the GCM that includes atmospheric dynamics over a static (no-dynamics) model when applied to the ESPRESSO data. This study adds to the growing body of literature employing GCMs to interpret high-resolution spectroscopic measurements of exoplanet atmospheres.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"102 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141381","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}