The High-Energy Gamma-ray Universe:
Results and Perspectives with Wide-Field Ground-Based Facilities

Announcements

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About

Rationale

Ground-based gamma-ray astronomy is now an established field, playing a decisive role in high-energy astrophysics thanks to the success of the current generation of imaging atmospheric Cherenkov telescopes (IACTs). Over the past decade we moved from the collection of a dozen nearby bright emitters to the detailed study of the nature of objects of various classes across the Galaxy, and of nearby extragalactic sources, spanning orders of magnitude in intrinsic luminosity, from tens of GeV to almost 100 TeV. The view provided by these instruments is now comparable, in many aspects, to that achieved with more traditional observational techniques. Such achievements, allied with the lack of new gamma-ray space missions in the medium-term future, further increases the expectations towards the start of operations of the Cherenkov Telescope Array (CTA).

In recent years we have also witnessed the coming of age of the wide-field particle arrays, chiefly represented by the Large High Altitude Air Shower Observatory (LHAASO),the High Altitude Water Cherenkov Observatory (HAWC), and the Tibet AS-gamma experiment which have extended the observational range of gamma-ray astronomy to beyond 100 TeV, significantly contributing to our understanding of the origin of cosmic rays and of extreme astrophysical phenomena. Since HAWC and LHAASO are both located in the Northern Hemisphere, plans are ongoing to install the first large-scale instrument of the kind below the line of the Equator, the Southern Wide-Field Gamma-ray Observatory (SWGO), from where the view of the Galactic Plane and Galactic Center are favoured. Preparations are also underway for the start of activities of a pioneer, small-scale southern-hemisphere pathfinder: the Andes Large-area Particle detector for Cosmic-ray Physics and Astronomy (ALPACA).

These two ground-based gamma-ray techniques available are highly complementary in their energy range of operations, observation modes and capabilities, with the extensive air shower (EAS) arrays being transit instruments capable of a continuous, wide-field surveying of the sky. The EAS arrays combination of vast collection areas with the continuous integration of signals over several years, confer them with the unique capability for a deep view of the Galaxy at the most extreme energies, expanding the observational reach of Astronomy up to the petaelectronvolt scale. In addition, their wide-field of view render them promising monitors of the extreme transient and variable universe, as recently showcased by the first serendipitous TeV detection of a GRB by LHAASO, making them potentially powerful instruments for multi-messenger astrophysics.

Objectives

This Focus Meeting takes place at a particular moment in the development of this new and emerging branch of observational astronomy, marked by the unprecedented achievements of arrays such as HAWC and LHAASO, which have driven the breakthroughs of the field and brought ultra-high-energy astronomy to maturity. It will also signal the launch of SWGO as the first project to build a wide-field array in the Southern Hemisphere, thus opening up a new window into the Galaxy at extreme energies.

The purpose of the meeting will be to present and review the current status of ground-based gamma-ray astronomy and its principal wide-field facilities, and discuss the many astrophysical problems that can be probed from their unique vantage point. With LHAASO being only on its first years of operation, but already delivering a wealth of breakthrough results, and SWGO approaching its construction phase as the first southern observatory of its kind, it is the right time to promote the discussion of this emerging and still little represented field in the existing IAU Commissions.

Supporting Divisions

• Division B Facilities, Technologies and Data Science
• Division D High Energy Phenomena and Fundamental Physics

Meeting Topics

1. Instrumentation and Experimental Status:
   Current and Future Facilities; Water Cherenkov and Particle Detectors;


2. The TeV to PeV Galaxy:
   Origin of Cosmic-Rays; PeVatrons; Extended Sources and Diffuse Emission; Galactic Center;


3. Extreme Extragalactic Sources:
   Ground-based Monitoring of VHE Transients; Gamma-ray Bursts; Gamma-ray Propagation Effects;


4. Synergies:
   Multi-wavelength Synergies; Multi-messenger Synergies (Neutrinos and Gravitational Waves); Synergies with IACTs and the CTA;


5. Astro-particles:
   Dark Matter Searches; Fundamental Physics Topics; Cosmological Probes.

Invited Speakers

TBD

SOC

Chairs

• Ulisses Barres de Almeida (CBPF, Brazil)
• Felix Aharonian (DIAS, Ireland)
• Zhen Cao (IHEP, China)
• Petra Huentemeyer (MTU, United States)
• Gustavo Romero (IAR, Argentina)

Members

• Markus Boettcher (NWU, South Africa)
• Patricia Caraveo (INAF-Bologna, Italy)
• Alberto Carraminana (INAOE, Mexico)
• Alessandro de Angelis (INFN-Padova, Italy)
• Elisabete de Gouveia Dal Pino (USP, Brazil)
• Brenda Dingus (UM, United States)
• Jim Hinton (MPIK, Germany)
• Elisa Prandini (Univ. of Padova, Italy)
• Andreas Reisenegger (UMCE, Chile)
• Takashi Sako (ICRR, Japan)
• Marcos Santander (UA, United States)
• Hao Zhou (SJTU, China)

Proceedings Editors

Ulisses Barres de Almeida, Patricia Caraveo, Michele Doro, Soebur Razzaque, Adrian Rovero

Important Dates

Please refer to the IAU GA XXXII website for details.

• Early Bird Registration: TBD
• Regular Registration: TBD
• Abstract Submission: TBD
• Notification on contribution: TBD
• General Assembly dates: August 6-15, 2024

Programme

This is a two-day meeting, focusing on each of the key topics below. Review talks of 30 minutes, invited talks of 20 minutes and contributed talks of 15 minutes are foreseen, all including time for discussion.

• Day 1 - Topic 1: Instrumentation and Experimental Status
• Day 1 - Topic 2: The TeV to PeV Galaxy
• Day 2 - Topic 3: Extreme Extragalactic Sources
• Day 2 - Topic 4: Synergies
• Day 2 - Topic 5: Astro-particles

Venue

Detailed information will be added when available.

Practical Information

Code of Conduct

The organisers are committed to ensuring that the focus meeting is supportive and inclusive of all members of the astronomical community, regardless of their expression of identity, their nationality, or their academic seniority. All participants must read and respect the IAU Code of Conduct on Ethics and Anti-Harassment in order to participate in this meeting.

Poster

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Proceedings

Detailed information will be added when available.

Contact

General Assembly

For any information regarding the General Assembly, please contact the National Organizing Committee: email tbd.

Focus Meeting

For information related to this Focus Meeting, please contact Ulisses Barres de Almeida (ulisses@cbpf.br) or one of the meeting chairs.