Astronomy & Astrophysics最新文献

{"title":"Fast partial-sky spherical harmonic transforms","authors":"J. Carron,M. Reinecke","doi":"10.1051/0004-6361/202661409","DOIUrl":"https://doi.org/10.1051/0004-6361/202661409","url":null,"abstract":"Our main motivations are the South Pole Observatory program targeting primordial gravitational waves from inflation and cosmic microwave background (CMB) lensing from South Pole Telescope, requiring high-resolution, numerically intensive work on small sky fractions. We aim to make significant improvements in the efficiency of general-purpose spherical harmonic transforms on limited regions of the sky. We extended the doubled Fourier sphere (DFS) method, which allowed it to handle more efficiently high numbers of locations on a region of the sphere. We achieved speed-up factors ranging from 3 to 10 on the SPT-3G main field, along with a BICEP3 deep footprint and much more on smaller patches, at the same level of accuracy. Our algorithm allowed us to eliminate the usual disadvantages of arbitrary pixelisations in comparison to isolatitude pixelisations (or flat‑sky approximations), making it ideal for ambitious workflows that require repeated spherical harmonic transforms on limited sky regions.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"84 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209155","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":"Multiwavelength study of EP250416a / GRB 250416C: An optically dark, long GRB with a late jet break","authors":"Guoying Zhao,Duo-Le Cao,Rong-Feng Shen,Hui Sun,Chi-Chuan Jin,Wei-Min Yuan,Chen-Wei Wang,Shao-Lin Xiong,Dmitry Svinkin,Dong Xu,Shuai-Qing Jiang,Peter G. Jonker,Yun Wang,Hao Zhou,Chang Zhou,Xinlei Chen,Kaushik Chatterjee,Xue-Feng Wu,Xiao-Feng Wang,Chun Chen,Yuan Liu,Andrew J. Levan,Jennifer Alexandra Chacon Chavez,Jonathan Quirola-Vásquez,Franz E. Bauer,Antonio Martin-Carrillo,Gregory Corcoran,Daniele B. Malesani,Dmitry Frederiks,Anna Ridnaia,Alexandra L. Lysenko,Mikhail Ulanov,Anastasia Tsvetkova","doi":"10.1051/0004-6361/202660325","DOIUrl":"https://doi.org/10.1051/0004-6361/202660325","url":null,"abstract":"We present a multiwavelength study of the γ/X-ray transient EP250416a (also designated GRB 250416C), triggered by the Einstein Probe (EP) Wide-field X-ray Telescope as well as by SVOM and Konus-Wind (KW). Observations spanning the γ-ray, X-ray, and optical bands facilitated a detailed analysis of the burst's prompt emission, afterglow evolution, and physical origin. GRB 250416C exhibits a burst duration of 30 s in the X-ray and 17.7 s in γ rays, and a joint spectral fitting of 0.5-5000 keV data yields E =342_ peak -232 ^ +90 keV. Optical spectroscopy of the afterglow, acquired with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South, yields a redshift of z=0.963. Accounting for the measured redshift, the isotropic energies are E =2.7_ X,iso -0.5 ^ +0.9 50 erg and E =7.34_ γ,iso -2.1 ^ +5.1 51 erg, aligning with the Amati relation for long GRBs. The fluence ratio ̊m S(25-50 keV)/S(50-100 keV)=0.78_ -0.12 ^ +0.10 classifies GRB 250416C as an X-ray rich GRB. The X-ray afterglow exhibits initial shallow decay (α ≈ -0.5) transitioning to a canonical decay phase (α ≈ -1), with a very late jet break at t∼ 1.5 ^ 10^6 s. This corresponds to a jet half-opening angle of þeta _j=10.6_ -1.8 +1.9 degrees. GRB 250416C is optically dark, as it shows only a faint r-band detection (r=24.16± 0.13 mag) from Gemini South-GMOS and a low optical-to-X-ray spectral index β_ ̊m OX = 0.3. This may be attributed to significant host-galaxy extinction, with a required A_V^ host =2.7± 0.3 mag derived from the extinction curve model.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"169 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209158","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":"CHEX-MATE: AMALGAM weak-lensing analysis of 41 Planck Sunyaev--Zel'dovich-selected galaxy clusters","authors":"Keiichi Umetsu,Raphael Gavazzi,Mauro Sereno,Nobuhiro Okabe,Emmanuel Bertin,Gianluca Castignani,Stefano Ettori,Fabio Gastaldello,Carlo Giocoli,Scott T. Kay,Junhan Kim,Maggie Lieu,Lorenzo Lovisari,Ben J. Maughan,Mario Nonino,Lorenzo Pizzuti,Etienne Pointecouteau,Gabriel W. Pratt,Mario Radovich,Elena Rasia,Mariachiara Rossetti,Harshda Saxena,Jack Sayers","doi":"10.1051/0004-6361/202661961","DOIUrl":"https://doi.org/10.1051/0004-6361/202661961","url":null,"abstract":"We present a weak-lensing shear analysis of 41 =3.53 Sunyaev--Zel'dovich (SZ)-selected galaxy clusters at 0.11 łe z łe 0.55 from the CHEX-MATE sample, using wide-field Subaru/Suprime-Cam and CFHT/MegaPrime imaging from the project. The azimuthally averaged weak-lensing signal, measured around the X-ray peak of each cluster, has a median signal-to-noise ratio of 6.5 per cluster. The 45^̧irc-rotated component has a median signal-to-noise ratio of -0.1 and ranges from -1.8 to $+1.8$, consistent with zero. We modelled the excess surface mass density profile of each cluster with a Navarro--Frenk--White profile to infer the weak-lensing mass and concentration constraints. The estimated total systematic uncertainty in the weak-lensing mass calibration is 8 =10^ Using a hierarchical Bayesian framework, we then derived weak-lensing-calibrated scaling relations for the halo concentration, c_200, as a function of M_200 and redshift, and for the SZ mass proxy, Msz, as a function of M_500 and redshift. In both regressions, we modelled the latent true-mass distribution of the selected sample and accounted for weak-lensing modelling biases and residual calibration uncertainty. For the Msz--M_500--z relation, we also included an effective treatment of the CHEX-MATE tier selection. At the pivot mass M_ 200 15 and redshift z=0.25, we find c_ 200 with an intrinsic scatter of 0.22 =0.83 =7 dex. The inferred normalisation and scatter are consistent with recent predictions for massive haloes, with no significant mass or redshift dependence over the probed range. For the mass proxy, our baseline regression yields Msz/M_ 500 at M_ 500 14 and z=0.25, with an intrinsic scatter of 0.10 dex. A restricted model with the mass slope fixed to unity and no redshift evolution yields 1- We also provide weak-lensing-calibrated posterior estimates of M_500 for the sample based on the baseline Msz--M_500--z relation. These results provide an initial weak-lensing mass calibration for CHEX-MATE multi-probe cluster studies.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"51 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209153","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":"Pushing HST to the limit. Detection completeness and morphology robustness of faint galaxies in the Extended Groth Strip field","authors":"Limin Lai,Zhao-Yu Li,Chao Ma,Yang A. Li,Luis C. Ho,Mingyang Zhuang","doi":"10.1051/0004-6361/202660867","DOIUrl":"https://doi.org/10.1051/0004-6361/202660867","url":null,"abstract":"Reliable catalogs at the faint limit are essential for statistical studies of galaxy evolution. However, detection and structural measurements of faint galaxies remain challenging. We evaluate detection completeness and structural parameter uncertainties of faint galaxies in the CANDELS/EGS field using mock images and observations from the Space Telescope (HST) and Space Telescope (JWST). The framework is also applicable to large high-redshift surveys, including , the upcoming Chinese Space Station Survey Telescope (CSST), and the Space Telescope. Hubble James Webb Euclid Nancy Grace Roman We detected sources in the EGS F160W mosaic using a 1.5σ threshold and quantified detection completeness and false-detection rates with realistic mock images. Mock galaxy-pair tests assessed blending effects on both source detection and structural measurements in fitting. In addition, the overlap with CEERS observations was used to derive an empirical criterion for separating true faint galaxies from fake detections using HST photometry. We identify 72,467 sources in the CANDELS/EGS field, including 57,444 fainter than 25 mag in F160W. Detection completeness exceeds 95% for objects brighter than 25 mag but declines to $<50%$ beyond 27 mag (with a false detection rate gtrsim50%). Structure parameters from single modeling are reliable down to m_ =25 mag. For galaxies at 25<m_ <27 mag, systematic biases in the H H index reach Δ n ) introduce measurable biases in recovered while Δ q decreases from approximately -0.03 to -0.27. Close companions (∼ 0.3 arcsec magnitudes and shapes, while the impact becomes negligible at larger separations. An empirical criterion based on m_ F814W-F160W color, R_50, and z_ separates true faint galaxies from false detections, reaching 72% completeness and 84% purity. It yields a final catalog of 59,646 objects, which is consistent with previous CANDELS measurements at bright magnitudes while reaching fainter limits.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"73 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210380","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":"Bifrost spectral inversions. Fast non-LTE solar chromospheric diagnostics from 3D simulations","authors":"Elias R. Udnæs,Tiago M. D. Pereira,Ignasi J. Soler Poquet,Luc Rouppe van der Voort","doi":"10.1051/0004-6361/202659837","DOIUrl":"https://doi.org/10.1051/0004-6361/202659837","url":null,"abstract":"Modern solar observatories produce vast amounts of detailed spectral data. To infer atmospheric parameters from these data, in particular for the solar chromosphere, requires immense computational resources. This problem is becoming more acute as spatial resolution improves, and faster methods are much needed to make sense of the data. Archive-based inversions provide a cost-effective way to infer atmospheric parameters from solar spectra; they involve building databases of synthetic spectra and atmospheric models. We extended this idea to a k-nearest neighbour inversion with non-LTE chromospheric spectra from a 3D radiative-magnetohydrodynamic simulation. Our database consists of 150 million þeline line profiles from a magnetically quiet simulation. We validated our method on a different simulation and then applied the database inversion to high-cadence observations taken with the Swedish 1-m Solar Telescope. We find excellent agreement between the observed and fitted spectra for almost the entire field of view. We recovered the chromospheric temperature and line-of-sight velocity and calculated the uncertainty in their inversions. The gas temperature has small uncertainties over a broad range of optical depths, and we recover a physically consistent solution, even beyond the line sensitivity region. Compared with the traditional inversion method, our approach is four orders of magnitude faster. Limitations and future improvements of the method are discussed.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"11 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209157","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":"Proton acceleration at interplanetary shocks: A numerical study for the HENON mission","authors":"L. Scarivaglione,G. Prete,S. Perri,G. Zimbardo","doi":"10.1051/0004-6361/202662437","DOIUrl":"https://doi.org/10.1051/0004-6361/202662437","url":null,"abstract":"The HENON CubeSat mission of ESA-ASI is designed to fly on a distant retrograde orbit at around 0.08 au upstream of Earth, for advance-time space-weather monitoring. The mission has a set of instruments that include an energetic particle detector measuring protons from 2 MeV to hundreds of MeV. Detecting energetic particle fluxes well in advance with respect to their impact on Earth is of pivotal importance for protecting technological infrastructures. In order to assess the features of energetic protons being accelerated at interplanetary shocks, we aim to set up a test-particle numerical simulation in which protons move in the drift approximation around a parallel shock transition and are accelerated each time they cross the shock according to a first-order Fermi process. During their motion they can propagate around the shock either diffusively or superdiffusively; particle transport indeed affects shock acceleration. Protons were injected at the shock with an energy distribution of about 10 keV and scattered in pitch angle by a collision operator. In the simulations, we varied the pitch-angle scattering time, the plasma speeds upstream and downstream of the shock, and the type of transport. In the superdiffusive case, a power-law distribution of scattering times was generated by mimicking a Lévy walk. Several runs were carried out in order to determine the parameter domain, which led to efficient acceleration and thus higher energies. For typical parameters, superdiffusive acceleration turns out to be somewhat faster than normal diffusive acceleration. We find that the main control parameter, which determines the maximum energy, appears to be the upstream shock speed, and that energies in the range of 2--10 MeV can be reached for upstream speeds in the shock frame, V_1, of the order of 300 km/s or more. Conversely, for a speed of V_1 łeq 150 km/s the proton energy reaches only a few hundred keV. These results facilitate our understanding of why many interplanetary shocks only accelerate ions up to moderate energies. Furthermore, the present study indicates that when the HENON particle instrument is able to detect energetic protons above 2 MeV, the shock speed in the spacecraft frame is relatively high, i.e. of the order of 800 km/s or more.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"280 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209159","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 local ultraviolet signature of Type Ia supernova environments from HST and MUSE","authors":"Lluís Galbany,Cullen Abelson,Alaa Alburai,Joseph P Anderson,Yago Ascasibar,Chris Ashall,Carles Badenes,Chris Burns,Èlia Diéguez Gurnés,Albert García Soto,Claudia P. Gutiérrez,Eric Y. Hsiao,Hanindyo Kuncarayakti,Andrew J. Levan,Joseph Lyman,Mark M. Phillips,Sebastian F. Sánchez,Ramon Sanfeliu,Maximilian Stritzinger,Danny Steeghs","doi":"10.1051/0004-6361/202661543","DOIUrl":"https://doi.org/10.1051/0004-6361/202661543","url":null,"abstract":"The local environment of a Type Ia supernova (SN Ia) traces the local stellar-population age (a statistical proxy for the progenitor age), star formation, dust, and chemical enrichment that can influence both its light-curve properties and its standardized luminosity. We assembled a homogeneous explosion-site dataset to test how near-ultraviolet (UV) imaging combined with optical integral-field spectroscopy improves the characterization of SN Ia environments and their connection to SN Ia observables. We analyzed 340 low-redshift SN Ia explosion sites observed with HST/WFC3 in F275W together with their matched VLT/MUSE spectroscopy. For each site, we measured local photometry and extracted a 1 kpc-aperture spectrum. We then modeled the stellar continuum with in a joint UV+optical fit, derived local stellar and gas-phase properties, and fit the SN light curves with /SALT3-NIR. We find that UV emission is detected at 235 of the 337 sites with valid HST imaging. The UV- and Hα-based star-formation-rate surface densities are strongly correlated, with the UV estimates systematically higher by about 0.5 dex. Including the UV constraint in the fit shifts local luminosity-weighted ages toward older values by a median of $+0.20$ dex for UV detections and $+0.45$ dex for UV nondetections, showing that UV data help break age-dust-metallicity degeneracies and substantially alter and tighten the inferred local stellar-population ages within the adopted modeling framework. Consistently, F275W-r is found to be very strongly correlated with the joint-fit stellar age. Within the 169-SN Ia calibration sample, the joint stellar age, the Hα specific star-formation rate (sSFR), and the UV sSFR all correlate strongly with the SALT3 stretch parameter, x_1, with significances above 6.8σ. After standardization, the residual Hubble-residual trends are weaker: the strongest trend is found for the local mass-weighted age, while the UV and Hα sSFRs show residual offsets of comparable sign and amplitudes of order ∼ 0.05 mag. None of the environmental dependencies of the Hubble residual exceeds 3σ. The results point to a dominant empirical association between light-curve stretch and a covariant young-stellar-population axis, largely absorbed by the standard light-curve corrections, while any residual luminosity dependence on the local environment is weaker and more subtle. If confirmed with larger samples, these residual trends may still become relevant for the younger SN Ia populations expected at higher redshift. Therefore, they should be tested in cosmology analyses with forthcoming Roman and JWST SN samples. STARLIGHT sncosmo STARLIGHT","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"14 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210394","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":"A deep learning approach to member identification and mass estimation in galaxy clusters","authors":"Zicheng Wang,Liping Fu,Wei Du,Wentao Luo,Wenxiang Pei,Zhu Chen,Zhijian Luo,Yicheng Li,Jiachen Qiu,Haoran Zhao,Kaiwen Mai,Weiming Ren","doi":"10.1051/0004-6361/202662195","DOIUrl":"https://doi.org/10.1051/0004-6361/202662195","url":null,"abstract":"Accurate dynamical mass estimates of galaxy clusters are essential for studies of cluster formation and evolution and for cosmological applications. However, interloper galaxies, which are not gravitationally bound to the cluster but are incorrectly identified as members, can bias dynamical mass measurements and increase their uncertainties. We developed a probabilistic deep-learning framework for cluster member identification and dynamical mass estimation and tested the sensitivity of the inferred masses to cluster miscentring and radially dependent incompleteness in controlled mock experiments. We used mock galaxy cluster catalogues to train a two-stage model. In this model, a long short-term memory (LSTM) network assigns membership probabilities to galaxies arranged by projected phase-space proximity. These probabilities are then used to construct membership-weighted projected phase-space density maps, from which a Bayesian neural network (BNN) infers cluster masses and predictive uncertainties. The LSTM membership probabilities are well calibrated and form an isoprobability envelope in the projected phase space, with the łangle p_ ̊m mem ̊angle=0.5 contour broadly tracing the empirical member--interloper transition. Applying a threshold of p_ th =0.5 provides a good balance between member completeness and purity, with high completeness within R_ proj <r_ 200 . Membership weighting lowers the residual scatter of the fiducial BNN mass estimator, mathrm BNN _ 2D ^ Mem , to σ_ε=0.120, a 19.5% reduction relative to the unweighted baseline, although the predictive uncertainties are not uniformly calibrated across the BNN models. Using the brightest cluster galaxy rather than the gravitational centre lowers the median inferred mass by up to 47.6%, with larger reductions at larger centring offsets. By contrast, removing 40% of eligible non-central galaxies within r_200 lowers it by 6.1% relative to complete catalogues.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"46 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209154","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":"JESSNet: Joint dEconvolution and Sparse Separation Network for HI 21 cm foreground cleaning","authors":"Athanasia Gkogkou,Victor Bonjean,Jean-Luc Starck,Pauline Gorbatchev,Marta Spinelli,Panagiotis Tsakalides","doi":"10.1051/0004-6361/202662836","DOIUrl":"https://doi.org/10.1051/0004-6361/202662836","url":null,"abstract":"i 21 cm intensity mapping, here considered over the redshift range z 0.58, particularly in the presence of a chromatic instrumental beam that couples angular foreground structure into the frequency direction. This problem is further complicated by incomplete sky coverage, as expected for realistic Galactic masks and survey footprints. -- i signal in single-dish intensity mapping observations affected by frequency-dependent beam distortions and masked sky regions. JESSNet advances the joint deconvolution and blind source-separation framework of DecGMCA and SDecGMCA through three methodological extensions. First, while the original formulation uses a single effective mixing model over the angular range being cleaned, JESSNet operates in angular windows, with an effective mixing matrix and a channel selection adapted to each scale. Second, JESSNet replaces the fixed starlet thresholding step with a learned spherical-wavelet ``learnlet'' sparse regularization operator. Third, whereas the original spherical implementation assumes full-sky coverage, JESSNet constrains the source estimates to the observed sky region, making the method applicable to Galactic masks and survey footprints. We tested the method on simulated SKA-MID-like observations covering 900 -- ̊m MHz , including H, i emission, Galactic and extragalactic foregrounds, thermal noise, and an oscillating in frequency MeerKAT-inspired beam model. i signal. Compared to applying JESSNet over a single angular range, the multiscale formulation significantly improves the reconstruction at low and intermediate angular scales and reduces residual beam-induced spectral features. The method also remains effective for a synthetic analysis footprint, preserving the H, i power spectra under incomplete sky coverage. i intensity mapping. The code used to produce the analysis and results has been publicly released, allowing the community to reproduce the pipeline and adapt it to future simulations and real observations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149150067","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":"Globular cluster Observations for Luminosity-dispersion Distances (GOLD): Project description and velocity catalogue","authors":"K. Fahrion,M. A. Beasley,A. Gvozdenko,I. Ortega-Casas,A. Ferre-Mateu,F. I. Aros,D. Dold,T. Jerabkova,S. S. Larsen,O. Müller,M. Rejkuba,K. L. Rhode,G. van de Ven","doi":"10.1051/0004-6361/202662786","DOIUrl":"https://doi.org/10.1051/0004-6361/202662786","url":null,"abstract":"We introduce and describe the Globular cluster Observations for Luminosity-Dispersion distances (GOLD) project, which has the principal aim of determining independent distances based on the globular cluster (GC) absolute magnitude-velocity dispersion (M_V - σ) relation calibrated with Milky Way GCs with Gaia distances. The project comprises observations of GCs in 19 early- and late-type galaxies taken with FLAMES/GIRAFFE on ESO's Very Large Telescope. So far, 17 galaxies have been observed. The spectra cover the wavelength range 8483--9000 Å,, including the calcium triplet region at a spectral resolution of R . Using primarily velocities to separate extragalactic sources from foreground stars, we present here our initial sample of 1062 GCs and 101 ultra-compact dwarf galaxies (UCDs). For more than 650 of these objects we present the first velocity measurement. We discuss the available photometry and size measurements, and show that our velocities are in good agreement with previous studies. Our velocity catalogues are made publicly available. Beyond the principal aim of obtaining precision distances, additional science to be explored with these data includes host galaxy halo dynamics and clustering analysis, mass-to light ratios of GCs and UCDs in the sample, the stellar initial mass function and black hole occupation fraction of the GCs, and chemical abundances from high-dispersion spectra. The spectra provide line-of-sight velocities with typical uncertainties of Δ v = 1-2 km s -1","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"38 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149150077","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}