arXiv subjects

Umberto Rescigno

Publications and source records attributed to Umberto Rescigno.

6 recordsLinked to original sources

arXiv2026

Embedding Equity, Diversity, and Inclusion in the WST Collaboration

The proposed Wide-field Spectroscopic Telescope (WST) is a next-generation telescope facility with a 12-meter primary mirror that may be operational in the 2040s. The project has a broad range of scientific goals and engages a large Community of more than 1000 members across multiple time zones, institutions, career stages, and professional roles. As for any large-scale scientific collaboration, building WST is therefore not only a technical and scientific challenge, but also a social and organisational one. This is particularly important in Astronomy and STEM disciplines more broadly, where marginalized groups remain underrepresented, particularly in leadership positions. In this paper, we describe the creation and first year of activity of the WST Equity, Diversity, and Inclusion (EDI) working group. We discuss how the group has worked to embed EDI considerations into the early phases of the Collaboration, and we present our ongoing and future projects aimed at broadening participation, accountability, and community sustainability, while delivering groundbreaking science. We also reflect on the challenges of sustaining EDI work in a large and rapidly evolving collaboration, including recognition of EDI contribution, uneven participation, communication across heterogeneous groups, and the need to connect facility-level initiatives with broader organisational and territorial responsibilities. We present our activities as a situated example of how EDI can be approached as part of the governance, communication, and community infrastructure required to build sustainable research environments.

astro-ph.IM↗

arXiv2026

Caught in the web: galaxy mergers along cosmic filaments

Galaxy clusters grow through the accretion of galaxies from groups, filaments, and other clusters. During this process, galaxies may undergo pre-processing in lower-density environments, where galaxy-galaxy mergers and other interactions can significantly alter their properties prior to cluster infall. We investigate the role of galaxy mergers in the pre-processing of galaxies prior to cluster infall by studying the spatial distribution of mergers across the cosmic web. We use a sample of 43,922 galaxies targeted by the 4MOST CHANCES survey in and around 33 low-redshift clusters (z < 0.07). Using Zoobot, a deep-learning framework trained on Galaxy Zoo data, we identify 698 galaxy mergers. We measure their distances to cosmic web filaments and compare them with those of non-merging galaxies. We find that galaxy mergers are significantly closer to filaments than the non-merging galaxy population, with this trend being strongest beyond the cluster virial radius. This suggests that filaments provide conditions conducive to mergers, possibly moderating relative velocities and enhancing gas availability. Our findings support a scenario in which filaments play a key role in transforming galaxies through pre-processing by promoting mergers before they enter cluster cores where star formation quenches.

astro-ph.GA↗

arXiv2025

Designing the Community Infrastructure for ESO's Next Transformational Facility. Equitable Governance and Sustainable Teams for 2040s Astronomy

The scientific ambitions of the 2040s will require large, interdisciplinary teams operating across continents, institutions, and increasingly heterogeneous political and funding landscapes. While significant effort is devoted to advancing the technical capabilities of future astronomical facilities, frameworks for coordinating and sustaining the associated community systems are often developed in parallel rather than embedded as coherent, long-term structures at the scale needed to fully realise this ambition. In this white paper, submitted as part of the ESO Expanding Horizons initiative, we draw on experience from established observatories and emerging collaborations to identify key community-level challenges. We argue that a central and transversal scientific challenge for the 2040s is to operate a flagship observatory in which access to telescope time, data, leadership, training, and career development is equitable across institutions, member states, and beyond. We propose that access and participation be treated as integral design parameters, embedded from the conceptual stage and sustained throughout the facility lifecycle, in order to ensure long-term scientific excellence, sustainability, and societal return.

astro-ph.IM↗

arXiv2025

Archaeological investigation of galaxies' evolutionary history in the cosmic middle ages

The cosmic Middle Ages, spanning the last 8-10 Gyr of the Universe, is a critical period in which massive early-formed systems coexist with global star formation quenching in less massive galaxies, yet galaxies experience further dynamical, morphological and chemical evolution. Understanding the relative role of internal drivers and of interaction with the evolving large-scale structures remains a highly complex and unsettled issue. To make transformative progress on these questions we must characterize the physical and kinematic properties (integrated and spatially resolved) of stellar populations in galaxies, fossil record of their past star formation and assembly histories, together with gas properties, across a wide range of masses and environmental scales, over this critical cosmic epoch. Volume-representative samples of 10^6 galaxies down to 10^9 solar masses are essential to fully trace the complex interplay between physical processes and to physically connect progenitor and descendant galaxy populations. This demands a deep and extensive survey with high signal-to-noise, medium-resolution, rest-frame optical spectroscopy. Current and planned facilities in the 2020-2030s cannot simultaneously achieve the required sample size, spectral quality, mass limit, and spatial coverage. A dedicated large-aperture spectroscopic facility with wide-area high-multiplex MOS and large field-of-view IFU is needed to provide transformative insights into the physical mechanisms regulating star formation and galaxy evolution.

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arXiv2025

Insights into environmental quenching at $z\sim1$: an enhancement of faint, low-mass passive galaxies in clusters

Understanding the processes that transform star-forming galaxies into quiescent ones is key to unraveling the role of environment in galaxy evolution. We present measurements of the luminosity functions (LFs) and stellar mass functions (SMFs) of passive red-sequence galaxies in four galaxy clusters at $0.8 < z < 1.3$, selected using deep VLT observations complemented with data from the GCLASS and GOGREEN surveys. We find a significant enhancement in the abundance of faint/low-mass passive galaxies in both the LFs and SMFs of all four clusters compared to the field. This is further evidenced by a shallower low-mass slope in the composite passive cluster SMF, which yields a Schechter parameter $α= -0.54^{+\,0.03}_{-0.03}$, compared to $α= 0.12^{+\,0.01}_{-0.01}$ for the field. Our findings indicate that quenching processes that act in clusters are enhanced compared to the field, suggesting that environmental quenching mechanisms may already be active by $z\sim1$. To reproduce the observed passive cluster SMF, we estimate that $25\pm5\%$ of the star-forming field population that falls into the cluster must have been quenched. Our results largely support traditional quenching models but highlight the need for deeper studies of larger cluster samples to better understand the role of environmental quenching in the distant Universe.

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arXiv2024

The first quenched galaxies, when and how?

Many quiescent galaxies discovered in the early Universe by \textit{JWST} raise fundamental questions on when and how these galaxies became and stayed quenched. Making use of the latest version of the semi-analytic model GAEA that provides good agreement with the observed quenched fractions up to $z\sim 3$, we make predictions for the expected fractions of quiescent galaxies up to $z\sim 7$ and analyze the main quenching mechanism. We find that in a simulated box of $685~{\rm Mpc}$ on a side, the first quenched massive ($M_{\star} \sim 10^{11} {\rm M}_{\odot}$), Milky Way mass, and low mass ($M_{\star} \sim 10^{9.5} {\rm M}_{\odot}$ ) galaxies appear at $z\sim 4.5$, $z\sim 6.2$, and before $z = 7$. Most quenched galaxies identified at early redshifts remain quenched for more than 1 Gyr. Independently of galaxy stellar mass, the dominant quenching mechanism at high redshift is accretion disk feedback (quasar winds) from a central massive black hole, which is triggered by mergers in massive and MW-mass galaxies, and by disk instabilities in low-mass galaxies. Environmental stripping becomes increasingly more important at lower redshift.

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