Astronomy & Astrophysics最新文献

{"title":"GPI+SPHERE detection of a 6.1 MJup circumbinary planet around HD 143811","authors":"V. Squicciarini, J. Mazoyer, C. Wilkinson, A.-M. Lagrange, P. Delorme, A. Radcliffe, O. Flasseur, F. Kiefer, E. Alecian","doi":"10.1051/0004-6361/202557104","DOIUrl":"https://doi.org/10.1051/0004-6361/202557104","url":null,"abstract":"<i>Context.<i/> Owing to its sensitivity to wide-orbit giant exoplanets, direct imaging is uniquely positioned to shed light on the interplay between protoplanetary disks and stellar hosts. In addition to constraining formation models, new detections are natural benchmarks for an atmospheric characterization.<i>Aims.<i/> The COBREX project performed an extensive reanalysis of archival observations from SPHERE and GPI using advanced post-processing techniques, that enhanced the detection sensitivity at close separation. Newly found companion candidates are being followed up to confirm new planets.<i>Methods.<i/> Following the detection of a companion candidate around the young (∼15 Myr) binary star HD 143811, we collected a new observation with SPHERE@VLT (0.95–1.67 μm) to confirm the presence of the source and to assess its physical bond to the target.<i>Results.<i/> We report the discovery of a new exoplanet orbiting HD 143811 at a projected separation of 0.43″ ∼ 60 au. Based on a 9-year-long baseline, we derive a mostly face-on and low-eccentricity orbit with a period of years. The luminosity of the planet, constrained through the H-band spectrum from GPI, H-band photometry from SPHERE/IRDIS and YJ upper limits from SPHERE/IFS, allows us to place strong constraints on the intrinsic temperature of the planet (<i>T<i/><sub>int<sub/> = 1000 ± 30 K), which corresponds to a mass of .<i>Conclusions.<i/> HD 143811(AB)b is the second planet ever discovered by GPI. It joins the small cohort of circumbinary planets discovered through imaging and becomes a prime target for follow-up formation, dynamical, and characterization studies.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145283186","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":"Starlight from JWST: Implications for star formation and dark matter models","authors":"Juan Urrutia, John Ellis, Malcolm Fairbairn, Ville Vaskonen","doi":"10.1051/0004-6361/202555390","DOIUrl":"https://doi.org/10.1051/0004-6361/202555390","url":null,"abstract":"We compared the star formation rate in different dark matter (DM) models with UV luminosity data from JWST up to <i>z<i/> ≃ 25 and legacy data from HST. We find that a transition from a Salpeter population to top-heavy Pop III stars is likely at <i>z<i/> ≃ 10, and that beyond <i>z<i/> = 10 − 15 the feedback from supernovae and active galactic nuclei is progressively reduced, so that at <i>z<i/> ≃ 25 the production of stars is almost free from any feedback. We compared fuzzy and warm DM models that suppress small-scale structures with the CDM paradigm, and find that the fuzzy DM mass > 5.6 × 10<sup>−22<sup/> eV and the warm DM mass > 1.5 keV at a 95% CL. The fits of the star formation rate parametrisation do not depend strongly on the DM properties within the allowed range. We find no preference over CDM for enhanced matter perturbations associated with axion mini-clusters or primordial black holes. The scale of the enhancement of the power spectrum should be > 25 Mpc<sup>−1<sup/> at the 95% CL, excluding axion mini-clusters produced for <i>m<i/><sub><i>a<i/><sub/> < 6.6 × 10<sup>−17<sup/> eV or heavy primordial black holes that constitute a fraction <i>f<i/><sub>PBH<sub/> > max[105 <i>M<i/><sub>⊙<sub/>/<i>m<i/><sub>PBH<sub/>, 10<sup>−4<sup/>(<i>m<i/><sub>PBH<sub/>/10<sup>4<sup/> <i>M<i/><sub>⊙<sub/>)<sup>−0.09<sup/>] of DM.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"125 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145283187","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":"Euclid preparation","authors":"A. Humphrey, P. A. C. Cunha, L. Bisigello, C. Tortora, M. Bolzonella, L. Pozzetti, M. Baes, B. R. Granett, A. Amara, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, S. Bardelli, C. Bodendorf, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, S. Camera, V. Capobianco, C. Carbone, J. Carretero, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, A. Da Silva, H. Degaudenzi, G. De Lucia, J. Dinis, F. Dubath, X. Dupac, S. Dusini, M. Farina, S. Farrens, S. Ferriol, M. Frailis, E. Franceschi, S. Galeotta, K. George, B. Gillis, C. Giocoli, A. Grazian, F. Grupp, L. Guzzo, S. V. H. Haugan, W. Holmes, I. Hook, F. Hormuth, A. Hornstrup, K. Jahnke, B. Joachimi, E. Keihänen, S. Kermiche, A. Kiessling, M. Kilbinger, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti, D. Maino, E. Maiorano, O. Mansutti, O. Marggraf, K. Markovic, M. Martinelli, N. Martinet, F. Marulli, R. Massey, H. J. McCracken, E. Medinaceli, S. Mei, M. Melchior, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, M. Moresco, L. Moscardini, E. Munari, R. Nakajima, S.-M. Niemi, J. W. Nightingale, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, V. Pettorino, S. Pires, G. Polenta, M. Poncet, L. A. Popa, F. Raison, R. Rebolo, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, E. Rossetti, R. Saglia, Z. Sakr, A. G. Sánchez, D. Sapone, R. Scaramella, P. Schneider, T. Schrabback, M. Scodeggio, A. Secroun, E. Sefusatti, G. Seidel, S. Serrano, C. Sirignano, L. Stanco, J. Steinwagner, P. Tallada-Crespí, A. N. Taylor, I. Tereno, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, L. Valenziano, T. Vassallo, A. Veropalumbo, Y. Wang, J. Weller, G. Zamorani, J. Zoubian, E. Zucca, A. Biviano, A. Boucaud, E. Bozzo, C. Burigana, M. Calabrese, R. Farinelli, N. Mauri, V. Scottez, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, V. Allevato, S. Anselmi, M. Ballardini, A. Blanchard, S. Borgani, S. Bruton, R. Cabanac, A. Calabro, G. Cañas-Herrera, A. Cappi, C. S. Carvalho, T. Castro, K. C. Chambers, S. Contarini, A. R. Cooray, J. Coupon, O. Cucciati, G. Desprez, A. Díaz-Sánchez, S. Di Domizio, J. A. Escartin Vigo, S. Escoffier, A. G. Ferrari, P. G. Ferreira, I. Ferrero, F. Fornari, L. Gabarra, K. Ganga, J. García-Bellido, E. Gaztanaga, F. Giacomini, G. Gozaliasl, A. Gregorio, A. Hall, H. Hildebrandt, J. Hjorth, J. J. E. Kajava, V. Kansal, D. Karagiannis, C. C. Kirkpatrick, L. Legrand, G. Libet, A. Loureiro, G. Maggio, M. Magliocchetti, F. Mannucci, R. Maoli, C. J. A. P. Martins, S. Matthew, L. Maurin, R. B. Metcalf, P. Monaco, C. Moretti, G. Morgante, Nicholas A. Walton, J. Odier, L. Patrizii, M. Pöntinen, V. Popa, C. Porciani, D. Potter, I. Risso, P.-F. Rocci, M. Sahlén, A. Schneider, M. Sereno, P. Simon, A. Spurio Mancini, C. Tao, G. Testera, R. Teyssier, S. Toft, S. Tosi, A. Troja, M. Tucci, C. Valieri, J. Valiviita, D. Vergani, G. Verza","doi":"10.1051/0004-6361/202452468","DOIUrl":"https://doi.org/10.1051/0004-6361/202452468","url":null,"abstract":"The <i>Euclid<i/> Space Telescope will image about 14 000 deg<sup>2<sup/> of the extragalactic sky at visible and near-infrared wavelengths, providing a dataset of unprecedented size and richness that will facilitate a multitude of studies into the evolution of galaxies. Although spectroscopy will also be available for some of the galaxies, in the vast majority of cases the main source of information will come from broadband images and data products thereof (i.e. photometry). Therefore, there is a pressing need to identify or develop scalable yet reliable methodologies to estimate the redshift and physical properties of galaxies using broadband photometry from <i>Euclid<i/>. Optionally, such methods could also include ground-based optical photometry. To address this need, we present a novel method developed as part of a ‘data challenge’ within the Euclid Collaboration to estimate the redshift, stellar mass, star-formation rate, specific star-formation rate, <i>E<i/>(<i>B<i/> − <i>V<i/>), and age of galaxies using mock <i>Euclid<i/> and ground-based photometry. The main novelty of our property-estimation pipeline is its use of the CatBoost implementation of gradient-boosted regression-trees together with chained regression and an intelligent, automatic optimisation of the training data. The pipeline also includes a computationally efficient method to estimate prediction uncertainties, and, in the absence of ground-truth labels, it provides accurate predictions for metrics of model performance up to <i>z<i/> ~ 2. We applied our pipeline to several datasets consisting of mock <i>Euclid<i/> broadband photometry and mock ground-based <i>ugriz<i/> photometry, with the objective of evaluating the performance of our methodology for estimating the redshift and physical properties of galaxies detected in the Euclid Wide Survey. The statistical metrics of prediction residuals vary depending on which mock catalogue and filters are tested. Nonetheless, the quality of our photometric redshift and physical property estimates are highly competitive overall, validating our modelling approach. However, at <i>z<i/> ≳ 3.5, the relative sparsity of galaxies resulted in unreliable redshift and physical property estimates, which we argue could be mitigated by building catalogues with better sampling of <i>z<i/> ≳ 3.5 galaxies or by switching to the use of spectral energy distribution fitting in this regime. We also find that the inclusion of ground-based optical photometry significantly improves the quality of the property estimation, highlighting the importance of combining <i>Euclid<i/> data with ancillary ground-based data from such surveys as the <i>Vera C. Rubin<i/> Observatory Legacy Survey of Space and Time and UNIONS.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145283184","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":"Euclid preparation","authors":"Abdurro’uf Abdurro’uf, C. Tortora, M. Baes, A. Nersesian, I. Kovačić, M. Bolzonella, A. Lançon, L. Bisigello, F. Annibali, M. N. Bremer, D. Carollo, C. J. Conselice, A. Enia, A. M. N. Ferguson, A. Ferré-Mateu, L. K. Hunt, E. Iodice, J. H. Knapen, A. Iovino, F. R. Marleau, R. F. Peletier, R. Ragusa, M. Rejkuba, A. S. G. Robotham, J. Román, T. Saifollahi, P. Salucci, M. Scodeggio, M. Siudek, A. van der Wel, K. Voggel, B. Altieri, S. Andreon, C. Baccigalupi, M. Baldi, S. Bardelli, A. Biviano, A. Bonchi, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, A. Caillat, S. Camera, G. Cañas-Herrera, V. Capobianco, C. Carbone, J. Carretero, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, M. Cropper, A. Da Silva, H. Degaudenzi, G. De Lucia, A. M. Di Giorgio, J. Dinis, H. Dole, F. Dubath, X. Dupac, S. Dusini, S. Escoffier, M. Farina, R. Farinelli, S. Farrens, F. Faustini, S. Ferriol, F. Finelli, S. Fotopoulou, M. Frailis, E. Franceschi, M. Fumana, S. Galeotta, B. Gillis, C. Giocoli, P. Gómez-Alvarez, J. Gracia-Carpio, A. Grazian, F. Grupp, W. Holmes, F. Hormuth, A. Hornstrup, P. Hudelot, K. Jahnke, M. Jhabvala, E. Keihänen, S. Kermiche, A. Kiessling, M. Kilbinger, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti, D. Maino, E. Maiorano, O. Mansutti, O. Marggraf, K. Markovic, M. Martinelli, N. Martinet, F. Marulli, R. Massey, E. Medinaceli, S. Mei, M. Melchior, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, A. Mora, M. Moresco, L. Moscardini, S.-M. Niemi, J. W. Nightingale, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, V. Pettorino, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, E. Rossetti, R. Saglia, Z. Sakr, D. Sapone, B. Sartoris, M. Schirmer, P. Schneider, T. Schrabback, A. Secroun, E. Sefusatti, G. Seidel, S. Serrano, P. Simon, C. Sirignano, G. Sirri, L. Stanco, J. Steinwagner, P. Tallada-Crespí, A. N. Taylor, I. Tereno, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, L. Valenziano, J. Valiviita, T. Vassallo, G. Verdoes Kleijn, A. Veropalumbo, Y. Wang, J. Weller, G. Zamorani, E. Zucca, E. Bozzo, C. Burigana, M. Calabrese, D. Di Ferdinando, J. A. Escartin Vigo, S. Matthew, N. Mauri, M. Pöntinen, C. Porciani, V. Scottez, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, V. Allevato, S. Anselmi, M. Archidiacono, F. Atrio-Barandela, M. Ballardini, D. Bertacca, A. Blanchard, L. Blot, S. Borgani, M. L. Brown, S. Bruton, R. Cabanac, A. Calabro, A. Cappi, F. Caro, C. S. Carvalho, T. Castro, F. Cogato, T. Contini, A. R. Cooray, O. Cucciati, G. Desprez, A. Díaz-Sánchez, S. Di Domizio, A. G. Ferrari, I. Ferrero, A. Finoguenov, A. Fontana, F. Fornari, K. Ganga, J. García-Bellido, T. Gasparetto, E. Gaztanaga, F. Giacomini, F. Gianotti, G. Gozaliasl, A. Gregorio, M. Guidi, C. M. Gutierrez, A. Hall, S. Hemmati, H. Hildebrandt, J. Hjorth, M. Huertas-Company, A. Jimenez Muñoz, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, C. C. Kirkpatrick, S. Kruk, M. Lattanzi, S. Lee, J. Le Graet, L. Legrand, M. Lembo, J. Lesgourgues, T. I. Liaudat, A. Loureiro, J. Macias-Perez, M. Magliocchetti, F. Mannucci, R. Maoli, J. Martín-Fleitas, C. J. A. P. Martins, L. Maurin, R. B. Metcalf, M. Miluzio, P. Monaco, C. Moretti, G. Morgante, K. Naidoo, Nicholas A. Walton, K. Paterson, L. Patrizii, A. Pisani, V. Popa, D. Potter, I. Risso, P.-F. Rocci, M. Sahlén, E. Sarpa, A. Schneider, D. Sciotti, E. Sellentin, M. Sereno, K. Tanidis, C. Tao, G. Testera, R. Teyssier, S. Tosi, A. Troja, M. Tucci, C. Valieri, D. Vergani, G. Verza, P. Vielzeuf","doi":"10.1051/0004-6361/202554516","DOIUrl":"https://doi.org/10.1051/0004-6361/202554516","url":null,"abstract":"The European Space Agency’s <i>Euclid<i/> mission will observe approximately 14000 deg<sup>2<sup/> of the extragalactic sky and deliver high-quality imaging of a large number of galaxies. The depth and high spatial resolution of the data will enable a detailed analysis of the stellar population properties of local galaxies through spatially resolved spectral energy distribution (SED) fitting. In this study, we test our pipeline for spatially resolved SED fitting using synthetic images of <i>Euclid<i/>, LSST, and GALEX generated from the TNG50 simulation using the SKIRT 3D radiative transfer code. Our pipeline uses functionalities in piXedfit for processing the simulated data cubes and carrying out SED fitting. We apply our pipeline to 25 simulated galaxies at <i>z<i/> ∼ 0 to recover their resolved stellar population properties. For each galaxy, we produce three types of data cubes: GALEX + LSST + <i>Euclid<i/>, LSST + <i>Euclid<i/>, and <i>Euclid<i/>-only. We performed the SED fitting tests with two stellar population synthesis (SPS) models in a Bayesian framework. Because the age, metallicity (<i>Z<i/>), and dust attenuation estimates are biased when applying only classical formulations of flat priors (even with the combined GALEX + LSST + <i>Euclid<i/> data), we examined the effects of additional physically motivated priors in the forms of mass-age and mass-metallicity relations, constructed using a combination of empirical and simulated data. Stellar-mass surface densities can be recovered well using any of the three data cubes, regardless of the SPS model and prior variations. The new priors then significantly improve the measurements of mass-weighted age and <i>Z<i/> compared to results obtained without priors, but they may play an excessive role compared to the data in determining the outcome when no ultraviolet (UV) data is available. Compared to varying the spectral extent of the data cube or including and discarding the additional priors, replacing one SPS model family with the other has little effect on the results. The spatially resolved SED fitting method is powerful for mapping the stellar population properties of many galaxies with the current abundance of high-quality imaging data. Our study re-emphasizes the gain added by including multi-wavelength data from ancillary surveys and the roles of priors in Bayesian SED fitting. With the <i>Euclid<i/> data alone, we will be able to generate complete and deep stellar mass maps of galaxies in the local Universe (<i>z<i/> ≲ 0.1), exploiting the telescope’s wide field, near-infrared sensitivity, and high spatial resolution.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"7 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145283182","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":"Time-dependent obscuration of a tidal disruption event candidate in the active galactic nucleus CSS100217","authors":"Ying Gu, Xiao Li, Xing-Qian Cheng, Dou-Dou Wang, Xue-Guang Zhang, En-Wei Liang","doi":"10.1051/0004-6361/202556722","DOIUrl":"https://doi.org/10.1051/0004-6361/202556722","url":null,"abstract":"CSS100217 is considered a peculiar tidal disruption event (TDE) candidate occurring in an active galactic nucleus (AGN). Unlike typical TDEs, for which the post-flare luminosity is equal to that pre-flare, CSS100217 decayed to ∼0.4 magnitudes fainter than its pre-flare <i>V<i/> band level. In this manuscript, we propose an obscured TDE model to explain the light curve of CSS100217. Assuming that the time-dependent obscuration, caused by the TDE unbound stellar debris, or by nuclear clouds moving around the supermassive black hole (SMBH), follows a Weibull distribution, we find that the light curve of CSS100217 can be described by the tidal disruption of a main-sequence star by a black hole. The total energy of the event derived from our fit is 7.23 × 10<sup>53<sup/> ergs and about 1.38 M<sub>⊙<sub/> of debris mass is accreted by the central SMBH. The model indicates that the contribution of the host galaxy to the observed pre-flare optical luminosity is not-significant compared to that of the AGN, which is consistent with the results of the spectral analysis. These results suggest that obscuration may play an important role in explaining the unusual TDE-like variability observed in CSS100217.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"77 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145283185","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":"Emulating the non-linear matter power spectrum in mixed axion dark matter models","authors":"Dennis Fremstad, Hans A. Winther","doi":"10.1051/0004-6361/202554621","DOIUrl":"https://doi.org/10.1051/0004-6361/202554621","url":null,"abstract":"In order to constrain ultra light dark matter models with current and near future weak lensing surveys, we need the predictions for the non-linear dark matter power spectrum. This is commonly extracted from numerical simulations or from semi-analytical methods. For ultra light dark matter models, such numerical simulations are often very expensive due to the need of having a very high force resolution, often limiting the simulations to very small simulation boxes that do not contain very large scales. In this work, we take a different approach by relying on fast approximate <i>N<i/>-body simulations. In these simulations, axion physics is only included in the initial conditions, allowing us to run a large number of simulations with varying axion and cosmological parameters. From our simulation suite, we used machine learning tools to create an emulator for the ratio of the dark matter power spectrum in mixed axion models – models where dark matter is a combination of CDM and axion – to that of ΛCDM. The resulting emulator only needs to be combined with existing emulators for ΛCDM to be able to be used in parameter constraints. We compared the emulator to semi-analytical methods, but a more thorough test to full simulations to verify the true accuracy of this approach is not possible at the present time and is left for future work.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"96 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145283188","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":"Why M-dwarf flares have a limited impact on the atmospheric evaporation of sub-Neptunes and Earth-sized planets","authors":"Andrea Caldiroli, Francesco Haardt, Elena Gallo, George King, Juliette Becker, Federico Biassoni, Riccardo Spinelli","doi":"10.1051/0004-6361/202555738","DOIUrl":"https://doi.org/10.1051/0004-6361/202555738","url":null,"abstract":"The habitable zones (HZs) of M-type stars are prime targets for exoplanet searches. These stars also exhibit significant magnetic flaring activity, particularly during their first billion years, which can potentially accelerate the evaporation of the hydrogen-helium envelopes of close-in planets. We employed the time-dependent photoionization hydrodynamics code ATES to investigate the impact of flares on atmospheric escape, focusing on an Earth-sized and a sub-Neptune-sized planet orbiting an early M-type star at distances of 0.01, 0.1, and 0.18-0.36 AU - i.e., around the inner and outer edges of the HZ. Stellar flaring was modeled as a 1-gigayear-long high-activity phase followed by a 4-gigayear-long low-activity phase, each characterized by an appropriate flare frequency distribution. We find that flares have a modest impact on the cumulative atmospheric mass loss - less than a factor of 2 - with the greatest absolute increase occurring when the planets are at their closest separation. However, the relative increase in mass loss between flaring and non-flaring cases is greater at larger orbital separations. This trend arises because as stellar irradiation fluctuates between quiescent levels and peak flares, the proportion of time that a planet spends in the energy-limited versus recombination-limited mass-loss regimes depends on its orbital separation. Additionally, we demonstrate the existence of a characteristic flare energy, between the minimum and maximum values, that maximizes the fractional contribution to flare-driven mass loss. Our results indicate that the flaring activity of M dwarfs does not significantly affect the atmospheric retention of close-in planets, including those within the HZ. The potential occurrence of rare super-flares, which current observational campaigns may be biased against, does not alter our conclusions.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"86 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277451","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 SOFIA Massive (SOMA) star formation Q-band follow-up","authors":"Prasanta Gorai, Kotomi Taniguchi, Jonathan C. Tan, Miguel Gómez-Garrido, Viviana Rosero, Izaskun Jiménez-Serra, Yichen Zhang, Giuliana Cosentino, Chi-Yan Law, Rubén Fedriani, Gemma Busquet, Brandt A. L. Gaches, Maryam Saberi, Ankan Das","doi":"10.1051/0004-6361/202556220","DOIUrl":"https://doi.org/10.1051/0004-6361/202556220","url":null,"abstract":"<i>Context<i/>. Hydrogen recombination lines (HRLs) are valuable diagnostics of the physical conditions in ionized regions surrounding high-mass stars. Understanding these lines, including broadening mechanisms and intensity trends, can provide insights into HII region densities, temperatures, and kinematics.<i>Aims<i/>. This study aims to investigate the physical properties of ionized gas around massive protostars by analysing the HRLs (H<i>α<i/> and H<i>β<i/>) in the Q band.<i>Methods<i/>. We carried out observations using the Yebes 40m radio telescope in the Q band (30.5–50 GHz) towards six high-mass protostars selected from the SOMA Survey (G45.12+0.13, G45.47+0.05, G28.20−0.05, G35.20−0.74, G19.08−0.29, and G31.28+0.06). The observed line profiles were analysed to assess broadening mechanisms, and electron densities and temperatures were derived. The results were compared with available Q-band data from the TianMa 65-m Radio Telescope (TMRT) that have been reported in the literature, and ALMA Band 1 (35–50 GHz) Science Verification observations towards Orion KL, analysed in this study.<i>Results<i/>. A total of eight H<i>α<i/> (n = 51 to 58) and ten H<i>β<i/> (n = 64 to 73) lines were detected towards G45.12+0.13, G45.47+0.05, and G28.20−0.05; there were no detections in other sources. We derived electron densities of ~1−5 × 10<sup>6<sup/> cm<sup>−3<sup/> and temperatures of 8000–10 000 K for the sources. However, for Orion KL, we obtained an electron density one order of magnitude lower, while its temperature was found to be more similar. Interestingly, G45.12 and G28.20 show an increasing intensity trend with frequency for both H<i>α<i/> and H<i>β<i/> transitions, contrary to the decreasing trend observed in Orion KL.<i>Conclusions<i/>. The line widths of the detected HRLs indicate contributions from both thermal and dynamical broadening, suggesting the presence of high-temperature ionized gas that is likely kinematically broadened (e.g. due to turbulence, outflows, rapid rotation, or stellar winds). Pressure broadening caused by electron density may also have a minor effect. We discuss different scenarios to explain the measured line widths of the HRLs. The contrasting intensity trends between the sources may reflect variations in local physical conditions or radiative transfer effects, highlighting the need for further investigation through higher-resolution observations and detailed modelling.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"86 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277460","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":"Rotational modulation and long-term evolution of the small-scale magnetic fields of M dwarfs observed with SPIRou","authors":"P. I. Cristofari, J.-F. Donati, S. Bellotti, É. Artigau, A. Carmona, C. Moutou, X. Delfosse, P. Petit, B. Finociety, J. Dias do Nascimento","doi":"10.1051/0004-6361/202554902","DOIUrl":"https://doi.org/10.1051/0004-6361/202554902","url":null,"abstract":"&lt;i&gt;Context&lt;i/&gt;. M dwarfs are known to host magnetic fields, impacting exoplanet studies and playing a key role in stellar and planetary formation and evolution. Observational constraints are essential to guide theories of dynamo processes believed to be at the origin of those fields, in particular for fully convective stars whose internal structure differs from that of partially convective stars. Observations reveal long-term evolution of the large-scale magnetic field reconstructed with Zeeman-Doppler imaging, and a diversity of their topologies. These large-scale magnetic fields, however, only account for a small amount of the unsigned magnetic flux at the stellar surface that can be probed by directly modeling the Zeeman broadening of spectral lines in unpolarized spectra.&lt;i&gt;Aims&lt;i/&gt;. We aim to investigate the long-term behavior of the average small-scale magnetic field of fully convective and partially convective M dwarfs with time, and assess our ability to detect rotational modulation and retrieve rotation periods from time series of field measurements derived from unpolarized spectra.&lt;i&gt;Methods&lt;i/&gt;. We performed fits of synthetic spectra computed with ZeeTurbo to near-infrared high-resolution spectra recorded with SPIRou between 2019 and 2024 in the context of the SLS and SPICE large programs. The analysis was performed on the spectra of two partially convective (AD Leo and DS Leo) and three fully convective (PM J18482+0741, CN Leo, and Barnard’s star) M dwarfs, along with EV Lac, whose mass is close to the fully convective limit. Our analysis provides measurements of the average small-scale magnetic field, which are compared to longitudinal magnetic field and temperature variation measurements (d&lt;i&gt;Temp&lt;i/&gt;) obtained from the same data.&lt;i&gt;Results&lt;i/&gt;. We detected the rotation period in the small-scale magnetic field series for four of the 6 stars in our sample. We find that the average magnetic field can vary by up to 0.3 kG throughout the year (e.g., CN Leo), or of up to 1 kG across rotation phases (e.g., EV Lac). The rotation periods retrieved from longitudinal and small-scale magnetic fields are found to agree within error bars. The d&lt;i&gt;Temp&lt;i/&gt; measurements are found to anti-correlate with small-scale magnetic field measurements for three stars (EV Lac, DS Leo, and Barnard’s star).&lt;i&gt;Conclusions&lt;i/&gt;. The results demonstrate our ability to measure rotation periods from high-resolution data through small-scale magnetic field measurements, provided that the inclination of the observed targets is sufficiently large. We observe long-term fluctuations of the average magnetic field that could indicate magnetic cycles in the parent dynamo processes. These long-term variations appear mainly uncorrelated with large-scale magnetic field variations probed through longitudinal field measurements. Large variations in the amplitude of the rotationally modulated signals, in particular, hint towards a change in the distribution of the surface inhomoge","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"124 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277461","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":"Rotational radial shear in the low solar photosphere","authors":"T. Corbard, M. Faurobert, B. Gelly, R. Douet, D. Laforgue","doi":"10.1051/0004-6361/202556102","DOIUrl":"https://doi.org/10.1051/0004-6361/202556102","url":null,"abstract":"<i>Context.<i/> Radial differential rotation is an important factor in stellar dynamo theory. In the Sun, helioseismology has revealed a near-surface shear layer in the upper 5–10 percent of the convection zone. At low to midlatitudes, the rotation velocity gradient decreases sharply near the surface. A depth gradient in rotational velocity was recently detected in the low photosphere using a differential interferometric method on spectroscopic data. Granular structures at different depths in the Fe I 630.15 nm line showed a systematic retrograde shift compared to continuum structures, which suggests a height-related decrease in angular velocity. This estimate depends on the assumed granulation coherence time.<i>Aims.<i/> We use a more direct approach to measure the differential rotational velocity at different photospheric heights.<i>Methods.<i/> We performed spectroscopic scans of the same granular region in Fe I 630.15 nm and Ca I 616.2 nm lines, and measured displacements of images at different line chords between consecutive scans. These observations require excellent seeing, stable adaptive optics correction, and scanning times shorter than the granulation lifetime. Adaptive optics stabilizes continuum images but not higher-altitude rotation differences. We used both THEMIS and HINODE Solar Optical Telescope Fe I 630.15 nm data to measure formation height differences via perspective shifts observed away from the disk center with the slit radially oriented.<i>Results.<i/> Measurements at disk center and ±25° latitude along the central meridian show a parabolic decrease in rotational velocity with height that reaches about 16% slower rotation at 80 km above the continuum. No significant difference is found between equator and ±25° latitudes.<i>Conclusions.<i/> The low photosphere is a transition zone between the convective and radiative layers. Our measurements provide new constraints on its dynamical behavior and valuable boundary conditions for numerical simulations of the Sun’s upper convection zone.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"39 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277458","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}