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In medio stat virtus: Enrichment history in poor galaxy clusters
No full textThe enrichment history of galaxy clusters and groups remains far from being fully understood. Recent measurements in massive clusters have revealed remarkably flat iron abundance profiles out to the outskirts, suggesting that similar enrichment processes have occurred for all systems. In contrast, the situation for galaxy groups is less clear, as their abundance profiles sometimes appear to decline with radius, challenging our understanding of the physical processes at these scales. In this paper, we present a pilot study aimed at accurately measuring the iron abundance profiles of MKW3s, A2589, and Hydra A, three poor clusters with total masses of M500 ≃ 2.0 − 2.5 × 1014 M⊙, placing them in an intermediate category between the scales of galaxy groups and massive clusters. For these systems, we also obtained nearly complete azimuthal coverage of their outer regions with XMM-Newton, thus allowing for detailed characterisation of their chemical properties at large radii. We show that, in the outskirts, abundance measurements are more likely to be limited by systematic uncertainties than by statistical errors. In particular, inaccurate modelling of the soft X-ray background can significantly bias metallicity estimates in regions where the cluster emission is faint. However, once these systematics are properly accounted for, the abundance profiles of all three clusters are found to be consistent with being flat, at a level of Z ∼ 0.3 Z⊙, in agreement with values observed in massive clusters. Using the available stellar mass estimates for the three systems, we also computed their iron yields, thereby beginning to probe a mass range that remains largely unexplored. We find Fe, 500 = 2.68 ± 0.34, 2.54 ± 0.64, and 7.51 ± 1.47 Z⊙ for MKW3s, A2589, and Hydra A, respectively, values that span the transition regime between galaxy groups and massive clusters. Future observations of systems with temperatures in the 2–4 keV range will be essential to further populate this intermediate-mass regime and to draw firmer conclusions about the chemical enrichment history of galaxy systems across the full mass scale
Galaxy sizes and compactness at Cosmic Dawn
No full textContext. The James Webb Space Telescope has found an unexpected population of high-mass galaxies (log(M★/M⊙)≳10) with extremely small effective radii (∼100 pc) at z ≳ 6. Also, the existence of an unusual size–mass relation has been claimed. These observations are only partially reproduced by current models, and the physics responsible for the observed relations is still under debate.
Aims. We aim to understand the physical mechanisms governing the size evolution of galaxies, and its dependence on their properties in the early Universe. We expect to unveil the formation channels of the observed compact galaxies.
Methods. We analysed 7605 snapshots for 169 galaxies of the state-of-the-art cosmological simulation suite FIRS
Investigating the influence of radio-faint active galactic nuclei on the infrared-radio correlation of massive galaxies
No full textContext. It is well known that star-forming galaxies (SFGs) exhibit a tight correlation between their radio and infrared emissions, commonly referred to as the infrared-radio correlation (IRRC). Recent empirical studies have reported a dependence of the IRRC on the galaxy stellar mass, in which more massive galaxies tend to show lower infrared-to-radio ratios (qIR) with respect to less massive galaxies. One possible, yet unexplored, explanation is a residual contamination of the radio emission from active galactic nuclei (AGNs), not captured through “radio-excess” diagnostics.
Aims. To investigate this hypothesis, we aim to statistically quantify the contribution of AGN emission to the radio luminosities of SFGs located within the scatter of the IRRC.
Methods. Our Very Large Baseline Array (VLBA) AGN-sCAN program has targeted 500 galaxies that follow the qIR distribution of the IRRC, i.e., with no prior evidence for radio-excess AGN emission based on low-resolution (∼arcsec) VLA radio imaging. Our VLBA 1.4 GHz observations reach a 5σ sensitivity limit of 25 μJy/beam, corresponding to a radio-brightness temperature of Tb ∼ 105 K. This classification serves as a robust AGN diagnostic, regardless of the host galaxy’s star formation rate.
Results. We detect four VLBA sources in the deepest regions, which are also the faintest VLBI-detected AGNs in SFGs to date. The effective AGN detection rate is 9%, when considering a control sample matched in mass and sensitivity, which is in good agreement with the extrapolation of previous radio AGN number counts. Despite the non-negligible AGN flux contamination (∼30%) in our individual VLBA detections, we find that the peak of the qIR distribution is completely unaffected by this correction. Although we cannot rule out a high incidence of radio-silent AGNs at (sub)μJy levels among the VLBA non-detections, we derive a conservative upper limit of < 0.1 dex of their cumulative impact on the qIR distribution. We conclude that residual AGN contamination from non-radio-excess AGNs is unlikely to be the primary driver of the M★ – dependent IRRC
Unveiling the small-scale web around galaxies with miniJPAS and DESI
No full textWe present the first statistical observational study detecting filaments in the immediate surroundings of galaxies, i.e. the local web of galaxies. Simulations predict that cold gas, the fuel for star formation, is channeled through filamentary structures into galaxies. Yet, direct observational evidence for this process has been limited by the challenge of mapping the cosmic web at small scales. Using miniJPAS spectro-photometric data combined with spectroscopic DESI redshifts when available, we constructed a high-density observational galaxy sample spanning 0.2 1010 M⊙ using all nearby galaxies as tracers, combined with a probabilistic adaptation of the DisPerSE algorithm designed to overcome limitations due to photometric redshift uncertainties. Our methodology was tested and validated using mock catalogues built with random forest models applied to a simulated lightcone. Besides recovering the expected increase in galaxy connectivity (defined as the number of filaments attached to a galaxy) with stellar mass, we show that our connectivity measurements agree with 3D reference estimates from the mock galaxies. Thanks to these filament reconstructions, we explore the relation between small-scale connectivity and galaxy star formation rate, finding a mild positive trend which needs to be confirmed by follow-up studies with larger sample sizes. We propose galaxy connectivity to local filaments as a powerful and physically motivated metric of environment, offering new insights into the role of cosmic structure in galaxy evolution
Velocity dispersion functions of pressure-supported galaxies in EAGLE simulations with varying active galactic nucleus feedback
No full textWe investigated the stellar velocity dispersion functions (VDFs) of pressure-supported galaxies in the EAGLE cosmological simulations. The central stellar velocity dispersion is one of the fundamental dynamical tracers of the total mass of galaxy subhalos, alongside luminosity and stellar mass. Because it reflects the gravitational potential, the stellar velocity dispersion is expected to be relatively insensitive to feedback from active galactic nuclei (AGNs), a critical process that regulates the connection between other galaxy observables and subhalo masses. To examine the impact of AGN feedback, we analyzed the VDFs from five EAGLE simulation runs, each adopting a different AGN feedback model: one “standard”, two “enhanced”, one “reduced”, and one with no AGN feedback. We computed the stellar velocity dispersions of pressure-supported galaxies using member stellar particles, mimicking fiber spectroscopy. The VDFs from the standard and enhanced AGN feedback models show little difference. However, contrary to our initial expectation that the VDF shape would be largely insensitive to AGN feedback, the simulations with reduced and no AGN feedback show a significant excess of high velocity dispersion galaxies (σ* > 200 km s−1) and a deficit of low velocity dispersion galaxies (100 < σ*(km s−1) < 200), compared to those with standard or enhanced AGN feedback. The presence of high velocity dispersion galaxies in the no-AGN model arises from enhanced central star formation, due to the absence of AGN-driven gas heating or expulsion. Our results demonstrate that the shape of the theoretical VDF is sensitive to the strength of AGN feedback. These predictions offer a theoretical benchmark for future observational studies of the galaxy VDF using large-scale spectroscopic surveys
Retraction Notice: The Use of Webgis as an Implementation of Smart Sustainable Cities Concept in Parepare City, South Sulawesi
No full textWe take a zero tolerance to any situation where fraudulent research is published in our journals. As a result, this article has been retracted by the Publisher because it is suspected to be a nonsensical computer-generated publication with a number of tortured phrases and irrelevant references.
Additional measures have been implemented to prevent these issues from reoccurring.
EDP Sciences is extremely grateful to anonymous whistleblowers and the Problematic Paper Screene
Retraction Notice: Study of the Moment of Drag and Lift on Different Air-foil Shapes and Thickness During Wind Tunnel Application: A Review
No full textWe take a zero tolerance to any situation where fraudulent research is published in our journals. As a result, this article has been retracted by the Publisher because it is suspected to be a nonsensical computer-generated publication with a number of tortured phrases and irrelevant references.
Additional measures have been implemented to prevent these issues from reoccurring.
EDP Sciences is extremely grateful to anonymous whistleblowers and the Problematic Paper Screene
Retraction Notice: Applying machine learning to soil analysis for accurate farming
No full textWe take a zero tolerance to any situation where fraudulent research is published in our journals. As a result, this article has been retracted by the Publisher because it is suspected to be a nonsensical computer-generated publication with a number of tortured phrases and irrelevant references.
Additional measures have been implemented to prevent these issues from reoccurring.
EDP Sciences is extremely grateful to anonymous whistleblowers and the Problematic Paper Screene
