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Overview of final results from the NIKA2 Sunyaev-Zeldovich Large Program
No full textThe NIKA2 SZ Large Program (LPSZ) is devoted to the highangular resolution SZ mapping of a representative sample of SZ-selected clusters, at intermediate to high redshift, drawn from the catalogues of the Planck satellite and of the Atacama Cosmology Telescope. Central to this program is the synergy between SZ observations and X-ray data, utilizing measurements from NIKA2 and XMM-Newton or Chandra. The main goal of this program is to provide the community with unprecedented measurements of cluster maps at 150 and 260 GHz, thermodynamic profiles and integrated quantities. This paper describes the LPSZ scientific objectives, the first public release and its scienceready products, the published results on individual clusters and the upcoming publications on the full sample
N2CLS: The NIKA2 view of the distant Universe
No full textThe N2CLS survey observed the GOODS-N and COSMOS fields at 260 GHz and 150 GHz with the NIKA2 camera, reaching the confusion limit in GOODS-N at 1.2 mm and approaching it at 2.0 mm. In this short proceedings, we present the results of the survey, including the source number counts, multiwavelength SED fitting, the dust mass function, the evolution of the dust mass density, and the physical characterization of the detected galaxy population
Multiwavelength Cross-Correlation Using Millimeter AGN Light Curves from the Atacama Cosmology Telescope
No full textWe present a pilot multiwavelength cross-correlation analysis of the blazar PKS 0208-512 between 2018 and 2023 using millimeter data from the Atacama Cosmology Telescope (ACT) and the Atacama Large Millimeter Array, optical data from the All-Sky Automated Survey for Supernovae, and γ-ray data from the Fermi Large Area Telescope. We report a near-zero time-lag between the optical and γ-ray bands, consistent with leptonic emission models, while the millimeter emission lags by a few weeks, suggesting millimeter emission originates from farther downstream in the jet. With the upcoming release of an ACT catalogue containing over 200 blazar light curves, these results highlight the potential of these light curves for time-domain active galactic nuclei studies and provide a foundation for extending this analysis to a larger blazar sample
The SZ-Mass scaling relation with the NIKA2 SZ Large Program
No full textIn Sunyaev-Zeldovich (SZ) cluster cosmology, accurately determining cluster masses is crucial for constraining cosmological parameters through cluster number counts. As the mass is not an observable, a scaling relation is needed to link cluster masses to the integrated Compton parameter Y, i.e., the SZ observable, to exploit data from large millimeter surveys. Former cosmological results use a scaling relation obtained with clusters at low redshift (z < 0.5) observed in X-ray and in SZ at an angular resolution above 1 arcminute. The SZ large program (LPSZ) of the NIKA2 collaboration uses a sample of clusters at intermediate to high redshift (from z = 0.5 to z = 0.9) observed at similarly high-angular resolution both in SZ and in X-ray. We present the SZ-Mass scaling relation parameters calibrated thanks to the LPSZ data
SHAPE
No full textWith the launch and application of next-generation ground- and space-based telescopes, astronomy has entered the era of big data, necessitating more efficient and robust data analysis methods. Most traditional parameter estimation methods do not have the capacity to reconcile differences between photometric systems. Ideally, we would like to optimally rely on high-quality observational data (e.g., from JWST) for calibrating and improving upcoming wide-field surveys, such as the Chinese Space Station Survey Telescope (CSST) and Euclid. To this end, we employed the self-organizing map (SOM) method and introduced a new approach that combines a SOM with a spectral energy distribution (SED). The resulting SOM-SED Hybrid Approach for efficient Parameter Estimation (SHAPE) is able to bridge different photometric systems and efficiently estimate key galaxy parameters, such as the stellar mass (M★) and star formation rate (SFR), leveraging data from a large and deep JWST/NIRCam and MIRI survey (PRIMER). As a test of the methodology, we focused on galaxies at z ∼ 1.5 − 2.5. To mitigate discrepancies between input colors and the training set, we replaced the default SOM weights with stacked SEDs from each cell, extending the applicability of our model to other photometric catalogs (e.g., COSMOS2020). By incorporating an SED library (SED Lib), we applied this JWST-calibrated model to the COSMOS2020 catalog. Despite the limited sample size and potential template-related uncertainties, SOM-derived parameters exhibit a good agreement with results from SED fitting using extended photometry. Under identical photometric constraints from CSST and Euclid bands, our method outperforms traditional SED fitting techniques in SFR estimation, exhibiting a reduced bias (–0.01 vs. 0.18) and a smaller σNMAD (0.25 vs. 0.35). With a computational efficiency capable of processing 106 sources per CPU per hour during the estimation phase, this JWST-calibrated estimator holds significant promise for next-generation wide-field surveys
Consistent patterns in trophic partitioning between sympatric salmonid fishes in two rivers of contrasting productivity
No full textIn environments with limited prey resources, coexisting and morphologically similar species that share these resources can compete strongly, potentially resulting in competition and trophic niche displacement. Alternatively, they can partition in their resource use to minimise their competitive interactions. Here, the trophic relationships of two sympatric salmonid fishes, brown trout Salmo trutta and Atlantic salmon Salmo salar, were assessed in two contrasting rivers, a chalk stream where the fish were very fast growing, and an upland stream where the fish were relatively slow growing. Using stable isotope analysis (δ13C and δ15N), the size and position of their stable isotope niches were assessed when the species were sympatric and, in the upland stream, compared between allopatry and sympatry. In both rivers and all sympatric sites, strong patterns of inter-specific stable isotope niche partitioning were evident. In both species in the upland stream, there were only minor differences between their isotope data between allopatry and sympatry, with the position of their isotopic niche similar in both contexts and with overlap in the 95% credible intervals of their isotopic niche sizes. This suggests inter-specific differences in their trophic ecology were driven by differences in functional morphology and habitat use than inter-specific interactions
Probing stellar rotation in the Pleiades with gravity-mode pulsators
No full textContext. Due to their proximity, the Pleiades are an important benchmark open cluster. Despite its status, asteroseismic analyses of its members are rare. In particular, the gravity-mode (g-mode) pulsators, which allow near-core stellar properties to be inferred, have not been analysed yet.
Aims. We aim to identify and analyse the population of g-mode pulsators in the Pleiades. Our focus lies on the internal rotation as measured from asteroseismology to obtain a well-defined sample of stellar rotation on the early main sequence.
Methods. Based on full-frame images from the Transiting Exoplanet Survey Satellite (TESS), we constructed light curves for intermediate-mass Pleiades members and searched for g-mode pulsators among them. For pulsators exhibiting period spacing patterns, we determined their near-core rotation rate and buoyancy periods. For all other g-mode pulsators, we estimated the near-core rotation rate based on the dominant mode frequency to obtain a comprehensive rotation rate distribution.
Results. Among our 105 target stars, we find 28 g-mode pulsators distributed across the entire upper main sequence, 19 of which are hybrid pulsators, but only three stars exhibit period spacing patterns in the current TESS data. The near-core rotation rates in A- and early F-type members are distributed between 1 and 3 d−1 without any clear mass-dependence. This distribution is much broader than the one in the similar open cluster NGC 2516. A comparison of the buoyancy periods shows that the Pleiades and NGC 2516 are of a similar asteroseismic age.
Conclusions. With the large population of g-mode and hybrid pulsators, the Pleiades constitute a valuable asteroseismic benchmark cluster, reaffirming its important role in stellar astrophysics
The vertical profile of the northern Io footprint auroral emission in the far-ultraviolet from Juno
No full textContext. The interaction between Io and the Jovian magnetosphere produces the auroral “Io footprint”, which can be observed in the ultraviolet thanks to the deexcitation of atmospheric H and H2 under electron precipitation. Since 2016, Jupiter has been explored with Juno’s Ultraviolet Spectrograph, which monitors the emission from 68 to 210 nm.
Aims. We used Juno observations of the Io footprint near the planetary limb to determine its vertical ultraviolet emission profile in the northern hemisphere. We simulated emission as a function of the altitude and the mean energy of the precipitating electrons, and we used the results to determine the energy spectrum associated with the footprint profile.
Methods. We estimated the source location of the Io footprint UV emission, and we extracted its vertical profile. We analyzed the variability of the emission altitude, and we derived the corresponding energy spectrum of precipitating electrons using TransPlanet. The results were compared with the in situ measurements from Juno’s particle detectors.
Results. The main spot emission peaks around ~500 km, with a variability of ~200 km correlated with longitude. The emission of the footprint tail within 20° from the main spot peaks around ~500±300 km, and it is moderately correlated with the magnitude of the magnetic field near Jupiter. The trans-hemispheric electron beam spot is located at ~300 km, and the associated precipitation appears depleted at low energy. The retrieved energy spectrum of the precipitation shows remarkable agreement with the particle measurements.
Conclusions. The longitudinal modulation of the Io footprint altitude suggests that the morphology of the torus affects the transmission of the Alfvén waves responsible for the acceleration of auroral electrons. The dependency of the footprint tail altitude on the magnetic field strength indicates that the magnetic field also plays a role in the acceleration mechanism
Further constraints on Jupiter’s primordial structure
No full textThe primordial structure of Jupiter remains uncertain, yet it holds vital clues on the planet’s formation and early evolution. Recent work used dynamical constraints from Jupiter’s inner moons to determine its primordial state, thereby providing a novel, formation-era anchor point for interior modeling. Building on this approach, we combine these dynamical constraints with thermal evolution simulations to investigate which primordial structures are consistent with present-day Jupiter. We present 4,250 evolutionary models of the planetary structure, including compositional mixing and helium phase separation, spanning a broad range of initial entropies and composition profiles. We find that Jupiter’s present-day structure is best explained by a warm (4.98−2.57+3.00 kB mu−1), metal-rich dilute core inherited from formation. To simultaneously satisfy constraints on Jupiter’s primordial spin, however, its envelope must have been significantly warmer (9.32−0.58+0.48 kB mu−1) at the time of disk dispersal. We determine Jupiter’s primordial radius to be 1.89−0.49+0.40 RJ. These results provide new constraints on Jupiter’s formation, suggesting that most heavy elements were accreted early during runaway gas accretion, and placing bounds on the energy dissipated during the accretion shock