Iberian AtLAST days

4 Jun 2026, 09:00 → 5 Jun 2026, 16:35 Europe/Madrid

Facultad de Químicas - Salón de Actos (Universidad Complutense de Madrid)

Francisco Miguel Montenegro Montes (IPARCOS - UCM), Gloria Cividanes (Universidad Complutense de Madrid)

This event will bring together the Spanish and Portuguese (sub-)mm communities to foster scientific and technical synergies around the future AtLAST facility.

In person attendance is encouraged for a better experience and collaboration opportunities, but since physical space is limited, we are offering a hybrid event.

Key dates

• 26th January. Abstract submission opening.
• 10th April. Deadline for abstract submission 
• 24th April. Full program available.
• 22nd May. Deadline for registration (or up to space limit reached)
• 4th-5th June. Iberian AtLAST days.

About AtLAST

The Atacama Large Aperture Submillimeter Telescope (AtLAST) (http://www.atlast-telescope.org) will be the most advanced 50-m-class single-dish telescope dedicated to exploring the (sub-)mm sky in the Southern Hemisphere, powered by renewable energy.

With its exceptional sensitivity and unprecedented field of view (~2°), AtLAST will enable transformational science across multiple areas of astronomy: from probing the dust and gas properties of large populations of high-redshift galaxies, to studying the circumgalactic and interstellar media in nearby galaxies — and in our own — thanks to its superb sensitivity to faint extended emission. AtLAST will also provide new insights into the Solar chromosphere, the chemical complexity of our Solar System and the Milky Way, and will revolutionize studies of the transient (sub-)mm sky through the combination of large-format cameras, high sensitivity, and excellent spatial resolution.

The AtLAST study has been funded twice by the European Union, with the current (second) project running through 2028. The consortium includes several Spanish institutions, namely the Institute of Space Sciences (CSIC-ICE), the European Solar Telescope Canarian Foundation (EST-CF), the Instituto de Astrofísica de Canarias (IAC), and the Universidad Complutense de Madrid (UCM), and it is aiming at an even larger partnership, including countries that are not yet formally part of the project. Through the Iberian AtLAST Days, we aim to present the project and its current developments, foster new collaborations, and broaden the community of researchers and engineers engaged in AtLAST from across both Portugal and Spain.

Funding

The Iberian AtLAST days meeting has received funding from the Spanish Red de Infraestructuras de Astronomía, through the call "Reuniones Abiertas 2026".
The AtLAST-2 project has received funding from the European Union's Horizon Europe research and innovation programme, under grant agreement No. 101188037.
FMM acknowledges support from PID2024-157374OB-I00, funded by MICIU /AEI /10.13039/501100011033 / FEDER, UE

Thursday 4 June

Registration and Welcome

Presentations I

1 AtLAST: Shaping together the next generation (sub)mm observatory

The coming decade will see a powerful suite of ground-based facilities come online, from radio to optical to multi-messenger astronomy. Yet a critical gap remains: a sensitive, high-resolution observatory at (sub-)mm wavelengths, essential for probing the cold Universe from planetary systems to cosmic structure. At the same time, the next generation of facilities must prioritise sustainability, aligning with Europe’s carbon-neutral ambitions.

The Atacama Large Aperture Submillimeter Telescope (AtLAST), a 50-metre-class single-dish concept addresses both challenges. Building on a strong foundation of European expertise and an active international community, the AtLAST2 project is advancing key technologies, exploring innovative and low-emission operational solutions, and consolidating the scientific and technical case for this transformative facility. We are at a pivotal stage of the project where concrete contributions from the community are essential, as we are actively moving into prototyping, system-level design, and validation of key technologies, while expanding the scientific and technical scope. This talk will highlight where and how astronomers, engineers, and instrumentation specialists can directly engage and help shape AtLAST, from defining its science priorities to developing its capabilities and sustainable infrastructure. Broad participation now will be critical to ensure that AtLAST fully delivers on its promise as a flagship facility for the 2030s and beyond.

Speaker: Evanthia Hatziminaoglou (IAC)

2 Instrument Overview and Conceptual Design of the 50-meter Atacama Large Aperture Submm Telescope (AtLAST)

From low-frequency radio through high energy gamma rays, the landscape of European facilities planned for the 2030s that can map large portions of the sky at subarcminute resolution is extensive. Yet facilities to map far-IR through mm wavelengths are lacking from this roadmap. The Atacama Large Aperture Submm Telescope (AtLAST) aims to fill much of this gap in our observational capabilities.

AtLAST is a concept for a groundbased next-generation 50-m observatory that is optimized to cover the same wavelength range as ALMA (350 microns to 10 mm) and to provide an unprecedentedly large instantaneous field of view (1-2 degrees, approximately 500 times the field of view of existing large single dish mm/submm facilities). It will also allow a suite of six nearly-unprecedentedly large instruments serving its vast range of science goals.

In this talk, I will provide an overview of the AtLAST conceptual design and the technological capabilities and requirements for its first generation of instrumentation, with an emphasis on how to get involved.

Speaker: Tony Mroczkowski (Institute of Space Sciences (ICE-CSIC))

3 From Star Formation to Cosmic Structure: The Transformative Science of AtLAST

AtLAST will transform our understanding of both the Milky Way and the extragalactic Universe by tracing the lifecycle of gas and dust across all scales and epochs. Within our Galaxy, its 50-meter dish and wide-field, high-resolution capabilities will map the interstellar medium (ISM) in unprecedented detail, revealing how giant molecular clouds fragment into stars and how magnetic fields and feedback shape star formation. It will resolve low-mass stars in clustered environments, characterize debris disks around nearby stars, and conduct large-scale polarimetric surveys to study the role of magnetic fields in galactic ecology.
Beyond the Milky Way, AtLAST will trace the cold baryon cycle from the local Universe to cosmic dawn, linking detailed maps of nearby galaxies with statistical studies of gas and dust in high-redshift systems. It will probe diffuse reservoirs, from circumgalactic gas to forming clusters, while uncovering obscured black hole accretion and transient phenomena. At survey scale, AtLAST will connect gas physics to halo growth and dark matter, delivering a unified view of galaxy evolution and cosmic structure in synergy with multi-wavelength facilities. By bridging Galactic and extragalactic science, AtLAST will reveal the hidden processes driving the assembly and evolution of galaxies across cosmic time.

Speakers: Teresa Huertas Roldán (Instituto de Astrofísica de Canarias), Jose Manuel Perez Martinez (Instituto de Astrofísica de Canarias (IAC))

11:00 Coffee break / Posters

Presentations II

4 Advancing W-Band KIDs for Low-Frequency Millimeter-Wave Astronomy

Superconducting detectors offer a powerful alternative to classical coherent receivers. Microwave Kinetic Inductance Detectors (KIDs) are a type of superconducting detector that combines intrinsic frequency multiplexing with a simple cryogenic harness, making them attractive candidates for astronomical observatories. In particular, KIDs have already demonstrated outstanding performance in several mm/submm instruments, such as NIKA2 and AMKID.
In this talk, we will present our recent developments in advancing this technology. Significant efforts are being made to push detection limits toward the low-frequency band (< 90 GHz) by exploring new superconducting materials, including titanium/aluminum (Ti/Al) or titanium/gold (Ti/Au) bilayers, and Al/Ti/Au trilayers. We will cover the full development cycle of these devices, including microwave simulation, nanofabrication pipeline and cryogenic characterization.
Electromagnetic analysis confirms the suitability of these designs for operation in the low-frequency band, achieving background-limited performance under high-background conditions, and showing a low-background sensitivity in the 10 -19 W/√Hz range.
These results pave the way for large-format W-band detector arrays for future millimeter-wave instruments, such as the AtLAST observatory.

Speaker: Víctor Rollano (Centro de Astrobiología (INTA-CSIC))

5 Magnification bias as an independent cosmological probe

Magnification bias offers a powerful and independent route to cosmological information, probing galaxy-matter correlations without relying on galaxy shapes, PSF modelling, or intrinsic-alignment corrections. Its sensitivity spans both geometry and growth: it simultaneously constrains the matter density, the amplitude of structure, and crucially the redshift evolution of dark energy below z≤1. Importantly, its parameter degeneracy directions differ from those of shear, BAO, and CMB data, making it a uniquely complementary and high-diagnostic-value probe for the next decade of precision cosmology. Beyond large-scale structure, magnification bias also provides a shape-independent window into halo mass density profiles down to sub-10 kpc scales, with recent pilot studies revealing characteristic features such as the "Einstein Gap" and signatures of massive satellite galaxies; applications that further illustrate the versatility of the technique.
However, the current potential of magnification bias remains limited by restricted sky coverage, catalogue inhomogeneities, confusion noise, and insufficiently precise redshift or number-count characterisation. A next-generation wide-field submillimetre facility like AtLAST — capable of uniform, deep surveys and spectroscopic mapping — would overcome these limitations and transform magnification bias into a competitive, high-precision cosmological tool. Combined with optical surveys from Euclid and LSST, AtLAST will deliver decisive constraints on dark energy, structure growth, and small-scale halo structure alike.

Speaker: Prof. Joaquín González-Nuevo (Universidad de Oviedo -- ICTEA)

6 The Magnetised Cosmic Web: Joint RM and SZ Probes with AtLAST

Magnetic fields are now known to permeate the full hierarchy of cosmic structure, from galaxies and clusters to filaments and the most diffuse phases of the cosmic web. However, their origin and evolution remain poorly constrained, particularly in low-density environments where direct observational probes are scarce.
In this talk, I will present recent progress in tracing the magnetised Universe using Faraday rotation measurements from wide-area radio surveys, including new results from ASKAP and LOFAR that probe the CGM, intragroup and intracluster medium, and large-scale filamentary structures. These measurements reveal the signature of magnetised gas well beyond cluster cores, but remain fundamentally limited by degeneracies between magnetic field strength, electron density, and path length.
I will highlight the transformative potential of combining these radio measurements with future Sunyaev–Zel’dovich (SZ) observations from AtLAST. The combination of Faraday rotation and SZ diagnostics offers a powerful, complementary approach to disentangling the density and magnetic field structure of the cosmic web, opening a new window on the co-evolution of gas and magnetic fields across cosmic time.

Speaker: Shane O'Sullivan (IPARCOS UCM)

7 Magnetic field in the circumgalactic medium of high-redshift galaxies using ASKAP

Magnetic fields are ubiquitous in galaxies and play a fundamental role in their dynamics and evolution. However, observational constraints on magnetic fields in the Circumgalactic Medium (CGM), particularly at intermediate to high z, remain limited. In this work, we investigate CGM magnetisation using a large sample of quasar Rotation Measures (RMs) from ASKAP, statistically separating sightlines that intersect foreground galaxies identified via Mg II absorption from control samples. After carefully mitigating Galactic foreground contributions, we detect a significant excess in the residual RM dispersion of 4.13 ∓ 0.91 rad m^-2 associated with intervening galaxies. This excess indicates the presence of coherent magnetic fields in galaxy halos, with strengths of 0.4 - 0.8 𝜇G over projected radii of 20-150 kpc, suggesting that substantial CGM magnetisation was already in place by z∼1.
These results provide constraints on the origin and amplification of magnetic fields in the CGM over cosmic time. In this context, upcoming facilities like AtLAST will play a transformative role. Through dust polarisation measurements, AtLAST will enable complementary probes of magnetic fields in the ISM and CGM in dusty, high-z systems, inaccessible to traditional RM-based techniques. The synergy between Faraday rotation studies and dust polarisation observations offers a powerful pathway to build a comprehensive, multi-scale picture of extragalactic magnetic fields across cosmic epochs.

Speaker: Sunil Malik (Complutense University of Madrid)

13:20 Lunch break / Poster session

Presentations III

8 AtLAST as a prebiotic molecule detector

In the past decade, Astrochemistry has witnessed an impressive increase in the number of detections of new molecular species in space. The majority of these detections are related to complex organic molecules (or COMs), defined as carbon-based compounds with more than five atoms in their molecular structure. Interestingly, some of these complex organics are of prebiotic interest, and hence, they are believed to be involved in the first biochemical processes that led to life. Recently, we have obtained ultra-sensitive, broadband spectral surveys toward the G+0.693 molecular cloud located in the Galactic Center, and known to be one of the richest chemical repositories of the Milky Way. Our spectral surveys carried out with the IRAM 30m, Yebes 40m and APEX telescopes, have allowed us to detect more than 25 new molecular species, which include precursors of ribonucleotides, nucleobases, amino acids, sugars, proto-proteins and proto-lipids, as proposed in theories of the origin of life. In this talk, I will present how AtLAST will be a key instrument in the discovery of new complex organic species, revealing the complete prebiotic inventory in the ISM.

Speaker: Dr Izaskun Jiménez-Serra (Center of Astrobiology (CAB))

9 Unveiling the hidden architecture from AGB winds to Planetary Nebulae

This project exploits the sensitivity, angular resolution, and high-frequency coverage of AtLAST to investigate key processes in late stellar evolution. We target compact and extended sources linked to post-AGB stars and planetary nebulae. For compact objects, we focus on pre-planetary nebulae with rotating disks, divided into high- and low-momentum subclasses. Using mm-wavelength radio recombination lines and salt emission (NaCl, KCl) as tracers, we will probe ionized cores, jet-launching regions, and dense disks, while C I lines will constrain photodissociation regions and total mass. AtLAST will enable the first statistically significant surveys of these faint tracers, currently limited to few detections. For extended sources, we will map circumstellar envelopes and nebulae to recover mass-loss history and address the “missing mass” problem. Combining CO isotopologues, dense gas tracers (HCN, HNC, HCO$^+$, CN), recombination lines, and C I emission, we will characterize the extent, kinematics, and physico-chemical conditions of faint halos that dominate the mass budget but are filtered out by interferometers. AtLAST’s mapping speed and multi-beam capability will recover diffuse emission on large angular scales with high sensitivity. These observations will constrain jet onset, disk formation, binarity, and chemical evolution across the AGB–pPN–PN transition, providing a comprehensive view of how evolved stars shed and recycle mass into the interstellar medium.

Speaker: Teresa Huertas Roldán (Instituto de Astrofísica de Canarias)

10 Unveiling the aromatic Galaxy with AtLAST

In recent years, two ultra-long (>1000 hr) single-dish spectral surveys toward the cold and quiescent molecular cloud TMC-1 have identified over 20 molecules containing five- and six-membered carbon rings, from benzonitrile (1 ring) to cyanocoronene (7 rings). These species are the simplest representatives of polycyclic aromatic hydrocarbons (PAHs), believed to account for a significant fraction of interstellar carbon. Despite their importance, their formation remains poorly understood. Distinguishing between top-down and bottom-up pathways requires detecting aromatic species across diverse interstellar environments, where physical conditions (e.g. Galactic location, evolutionary stage, temperature, turbulence, and cosmic-ray ionisation rate) leave distinct chemical signatures. The recent detection of benzonitrile in turbulent Galactic Center clouds shows that aromatic chemistry can survive harsh conditions, suggesting that it may be widespread throughout the entire Galaxy. To confirm this hypothesis, we need to detect large samples of aromatic species towards multiple of Galactic molecular clouds, achievable only with a single dish facility with significantly improved line sensitivity (< 0.1 mK). In this talk I will demonstrate how AtLAST observations in Band 1 (30-50 GHz) will enable the detection of several aromatic species within a few hours, enabling a systematic exploration of the Galaxy’s aromatic content.

Speaker: Dr Víctor M. Rivilla (Centro de Astrobiología (CAB), CSIC-INTA)

11 Simulating mapping observations with AtLAST

The maria simulator (https://thomaswmorris.com/maria/) is a python-based, comprehensive tool for simulating mapping observations with direct-detection instruments such as kinetic inductance detectors or bolometers. Ongoing work includes expanding its functionality to include spectroscopy and the use of GPU-accelerated code. I will provide a quick demonstration of its capabilities through easy, step-by-step pedagogical jupyter notebooks in order to help jumpstart your AtLAST science forecasting efforts.

Speaker: Thomas Morris (Yale University)

16:25 Coffee break / Posters

Presentations IV + Discussion

12 Constraining Black Hole Demographics with SKAO: From High-Redshift AGN to Merging SMBHs

Understanding the growth and evolution of supermassive black holes (SMBHs) across cosmic time remains a central challenge in astrophysics. Radio-loud active galactic nuclei (AGN), through their relativistic jets, provide a powerful probe of SMBH accretion and feedback, enabling studies of these processes even in the early Universe.

This talk will present ongoing and forthcoming scientific programmes in the context of the Square Kilometre Array Observatory (SKAO), aimed at constraining the demographics of rare SMBH populations. These include high-redshift (z ≳ 4) radio-loud AGN, as well as dual and recoiling SMBHs produced during galaxy mergers. The limited census of these systems continues to highlight key gaps in our understanding of jet physics, SMBH assembly, and merger-driven evolution.

To address these challenges, we are developing data-driven methodologies that combine wide-area radio surveys (e.g., ASKAP/EMU and future SKAO observations) with high-precision optical astrometry from Gaia, alongside multi-wavelength AGN diagnostics, enabling the systematic identification of otherwise elusive SMBH systems.

Looking ahead, SKAO will deliver transformative gains in sensitivity and survey speed, opening a new discovery space for faint and distant radio sources. In synergy with future (sub-)mm facilities such as AtLAST, these capabilities will enable a comprehensive, multi-phase view of SMBH growth and its role in shaping galaxy evolution across cosmic time.

Speaker: Sonia Anton (Univ Coimbra & CFisUC)

13 Full-Stokes monitoring of AGN jets with large (sub-)mm and radio facilities

Blazars, the jetted AGN with their axes closely aligned to our line of sight, comprise one of the most energetic, long-lived phenomena, dominate the gamma-ray sky and are possible neutrino emitters. The low-energy part of their SEDs is understood as incoherent synchrotron emission from their jets, which spans from radio to optical, UV or even X-rays and is both linearly and circularly polarized. On top of their persistent broadband emission, blazar jets often show pronounced variability across the electromagnetic spectrum with timescales from days/months down to minutes.

Here, I will demonstrate our efforts to capture the complex phenomenology of blazar jets through dedicated multi-wavelength polarization monitoring programs using several large (sub-)mm and radio facilities – such as POLAMI, SMAPOL, BEAM-ME and QUIVER – and in coordination with other multi-wavelength campaigns, including IXPE or MAGIC. Our observations, which cover two decades of frequency (2.6—230 GHz), follow the flux density and polarization variations of blazars with high cadence to constrain the jet physical conditions and dynamics. I will present the various challenges of high-precision, circular and linear polarimetry, the unique benefits of long monitoring programs to keep track of the efficiency and overall quality of the instrument and discuss future prospects for deep, polarimetric observations of large, statistically robust samples using high sensitivity and wide FoV facilities, such as AtLAST.

Speaker: Ioannis Myserlis (Institut de Radioastronomie Milimétrique (IRAM))

14 User survey + Discussion

Friday 5 June

Presentations V

15 Yebes Observatory: expertise in single-dish radio astronomy, receiver technology and space geodesy as a contribution to the AtLAST era

Yebes Observatory has accumulated over five decades of experience in radio astronomy, technological development and space geodesy, making it a potential relevant partner in the design and future operation of next-generation facilities such as AtLAST.

At its core, Yebes operates a 40-meter single-dish radio telescope equipped with ultra-wideband, highly sensitive cryogenic receivers covering bands up to 90 GHz, working both as a standalone facility and as part of major VLBI networks. It has a long track record in high-sensitivity, wide bandwidth single-dish operations that directly mirrors AtLAST's observational philosophy.

The observatory also hosts a receiver technology group with 40 years of experience designing and building cryogenic front-ends and low-noise amplifiers for radio astronomy, with contributions to various international telescopes and instruments like ALMA & IRAM, and expertise in wideband receiver design directly applicable to the instrumentation challenges of a 50-meter class submillimeter telescope.

Yebes is additionally a geodetic core station contributing to the maintenance of the ITRF and ICRF, rounding out a uniquely broad institutional profile for a mid-sized observatory.

Speaker: Pablo de Vicente (Observatorio de Yebes (IGN))

16 Recent and future upgrades to the IRAM 30-meter telescope

The IRAM 30-meter telescope is a top-class single-dish millimetre facility. It has been running around the clock for around forty years. Since 2021, we have been started an ambitious process of upgrade of the telescope, aiming at keeping our telescope as a reference in its niche. Recently finished upgrades include a new, state-of-the-art servo control system that is allowing us to open new avenues as a high-performance mapping machine; also, we have improved the main dish surface by replacing the paint cover: this has yield in a huge improvement of the performance in day time, while keeping the optical quality in night time.
Currently on-going upgrades include: the replacement of obsolete VME equipment, the improvement and rationalisation of the time-distribution system and the automation of the VLBI configuration functionality (see presentation from P. Torné). In the immediate future, a thorough revision and upgrade of our thermal control system will be carried out. and providing the operation with enhanced monitoring capabilities.
Our monitoring capabilities have been greatly enhanced: now we can monitor a much larger amount of telescope parameters; user-friendly, Grafana-based interfaces are now used, in line with other modern observatories.
At a longer-term, new instruments are being planned. In particular, the future ALHAMBRA multi-beam millimetre receiver will hugely boost our mapping capabilities, specially in combination with the high-speed tracking capabilities.

Speakers: Manuel Castillo-Fraile (Institut de Radioastronomie Millimétrique - IRAM), Miguel Sánchez-Portal (Institut de Radioastronomie Millimétrique - IRAM)

17 Synergies between AtLAST and LSST

A new era in ground-based optical astronomy is about to start with the completion of the Vera Rubin Observatory in Cerro Pachón (Chile) and the beginning of the Legacy Survey of Space and Time (LSST). End of 2024, the Vera Rubin Observatory completed successfully comprehensive systems tests with the engineering test camera (or commissioning camera, ComCam). In early March 2025, the largest digital camera in the world, the LSST Camera, was installed on the 8-4-meter Simonyi Survey telescope and the commissioning started. In June 2025, first results were announced worldwide. It is expected that the 10-years LSST survey of the southern sky will begin in the coming months. In this talk, I will review the status of the Vera Rubin Observatory, the main science programs, and the synergies between AtLAST and LSST. On February 25 2026, the Rubin Observatory began streaming transient and variable alerts to the scientific community. I will give a quick overview and examples of the Rubin alerts and how they are processed by the Rubin Observatory and the LSST brokers.

Speaker: Ismael Pérez-Fournon (Instituto de Astrofísica de Canarias)

18 Designing a sustainable off-grid power system in the Atacama Desert for AtLAST: a techno-economic, environmental, and social approach

The Atacama Desert in the north of Chile is an ideal location for astronomical facilities, hosting multiple observatories, some of which rely on fossil fuels for power because they are not connected to the national grid. However, climate change concerns and risks related to fossil fuel price fluctuations have driven consideration of renewable energy sources to power these infrastructures. Particularly, the Atacama Large Aperture Submillimeter Telescope (AtLAST) is the first astronomical project in the Chajnantor plateau to consider renewable energy sources from the design phase, while also exploring options to involve local communities in this solution. Considering this, we explore various scenarios for the energy system of this telescope, assessing and integrating techno-economic considerations along with Life Cycle Assessment. We show that a renewable energy system can power the telescope while minimizing overall system costs and environmental impacts. Furthermore, by involving the nearby communities through a participatory multi-criteria tool, the renewable energy solutions for the telescope can also help meet part of the community’s electricity demand, promoting a socially accepted system. These results highlight the opportunities for astronomical infrastructure to transition to renewable energy sources, thereby contributing to local sustainability.

Speaker: Guillermo Valenzuela-Venegas (Department of Technology Systems, University of Oslo)

11:00 Coffee break / Posters

Presentations VI + Discussion

19 CMB research at the IAC. Science and Technology Synergies for AtLAST

I will present the current status, recent results, and future plans of the experiments carried out by the CMBLab at the Teide Observatory (Tenerife, Spain), with a particular focus on their scientific and technological relevance for AtLAST.

In particular, I will highlight how ongoing efforts in CMB observations, including instrumentation plans, development of advanced detector and readout technologies, RFI mitigation and calibration strategies, can inform and complement the science case of AtLAST.

Speaker: Jose Alberto Rubiño Martín (IAC)

20 Mock redshift surveys of the (sub-)mm-wavelength sky

We present two mock redshift surveys of the dusty star-forming galaxy population based on N-body simulations that reproduce the observed surface density of galaxies at 0.5 to 2.0mm. The largest simulated area (100 sq. deg) allows us to identify gravitationally bound systems, trace their assembly histories, and quantify the redshift evolution of their galaxy content and size. We find a strong evolution in the fractional contribution of different star-forming galaxy populations within cluster progenitors. Luminous infrared galaxies are ∼20–40 per cent of the cluster/protocluster members, with the more luminous systems concentrating further into the centers at z > 1.5. Based on these mock catalogs we provide observational predictions for TolTEC on the 50m LMT and AtLAST.

Speaker: Prof. Itziar Aretxaga (CAB CSIC-INTA. Spain)

21 Surveying galaxy clusters in formation in the distant Universe with AtLAST

Galaxy clusters are the largest virialized structures in the Universe, yet their assembly at z>2 remains poorly understood. Their progenitors, protoclusters, span tens of Mpc hosting gas-rich, dust-obscured galaxies in diffuse, low-surface-brightness environments. (Sub-)millimeter observations uniquely trace the molecular gas and dust fueling rapid galaxy growth, but current facilities lack the mapping speed, surface-brightness sensitivity, and field of view to probe these scales. A next-generation 50m-class single-dish telescope such as AtLAST would enable wide-area, high-sensitivity spectral-imaging surveys of high-redshift protoclusters, capturing both extreme (sub-)millimeter galaxies and the bulk of star-forming systems in feasible integration times. Crucially, AtLAST would recover extended emission inaccessible to interferometers, providing the first complete view of the large-scale baryon cycle in forming clusters. Uniform multiline CO, [CI], and [CII] observations, including the CO SLED, across statistically significant samples will quantify the cold gas budget and its spatial distribution, revealing where star formation occurs and tracing gas accretion and cooling. I will highlight the key challenges limiting protocluster studies and show how AtLAST, in synergy with wide-field optical-to-NIR surveys, overcomes them to deliver the multi-scale, multiphase view needed to understand how galaxies, gas, and dark matter assemble in the densest regions of the early Universe.

Speaker: Dr Jose Manuel Perez Martinez (Instituto de Astrofísica de Canarias (IAC))

22 Discussion

13:25 Lunch break / Poster session

Presentations VII

23 Participation in SKAO Science Data Challenges by an HPC resources provider - impressions and some lessons learned

We will report on the activity the of Laboratory for Advanced Computing of the University of Coimbra (UC-LCA) within the SKAO data challenges, especially with the latest SDC3a and SDC3b.

We will focus on the interaction had with the groups assigned to UC- LCA regarding the High Performance Computing (HPC) resources provided and challenges related to data transfer and processing using the usual HPC environment. We will provide some reflections on the use of these resources from the radio-astronomical community.

We hope that those experiences can be valuable for the technical implementation of the AtLAST operations schema, including the distribution and processing of the massive data volumes expected to come from AtLAST instruments.

Speaker: Pedro Alberto (Universidade de Coimbra)

24 Pulsars, Magnetars, and Fast Transients with AtLAST

Time-domain astrophysics is rapidly expanding into the millimeter and submillimeter regime, opening a largely unexplored window on compact objects and fast transients. In this context, the planned Atacama Large Aperture Submillimeter Telescope (AtLAST) will provide a powerful new platform to study the transient and high-energy Universe at these wavelengths. This talk will review key time-domain science cases at (sub)millimeter wavelengths, focusing on pulsars, magnetars, and Fast Radio Bursts, where detections of high-frequency emission are key to probing emission physics and reducing propagation effects. Building on current results, we will discuss how AtLAST can play a major role in this field through its large field of view and sensitivity. We will also outline the critical instrumental and operational requirements (particularly wideband receivers and high-time-resolution backends) needed to fully exploit this new discovery space.

Speaker: Pablo Torne (Instituto de Radioastronomia Milimetrica (IRAM))

25 Extended Molecular Gas in Protoclusters: A Science Case for AtLAST

The Atacama Large Aperture Submillimeter Telescope (AtLAST) will open a new window on the cold molecular gas content of galaxies across cosmic time. With its wide-field mapping, high surface-brightness sensitivity, and ability to detect low-J CO emission, AtLAST will trace diffuse, extended molecular gas in dense environments at high redshift. This is key to understanding how environmental processes shape galaxy evolution and revealing the origin of the intracluster medium.

We demonstrate the feasibility of this approach using deep CO(1–0) observations with the Australian Telescope Compact Array (ATCA). In the Spiderweb protocluster (z=2.2), we discovered massive (>40 kpc), extended molecular gas reservoirs in star-forming galaxies - unexpected given predictions of environmental suppression.

Within our ATCA Large Program COALAS, we obtained 475 hours of observations, identifying such reservoirs in a significant fraction of galaxies and assembling the largest sample to date. These reservoirs likely trace early stages of the proto-intracluster medium, indicating that dense environments at z=2 host diffuse molecular gas.

Such detections remain observationally challenging. AtLAST will overcome these limitations through sensitive, large-area surveys, enabling statistical studies across environments. This will allow us to quantify how environment affects gas content, morphology, and star formation, and trace the emergence of the proto-intracluster medium in the early Universe.

Speaker: Helmut Dannerbauer (Instituto de Astrofísica de Canarias)

26 Concluding remarks