The 2nd LHAASO Symposium

20 Mar 2025, 09:00 → 25 Mar 2025, 22:00 Asia/Hong_Kong

Henry Cheng International Conference Center

Zhen Cao (高能所)

LHAASO (Large High Altitude Air Shower Observatory) has provided crucial insights into the origin and nature of cosmic rays, particularly in the ultra-high-energy regime. Its results also have implications for multi-messenger astronomy, as LHAASO can detect gamma rays in coincidence with other messengers, such as neutrinos and gravitational waves.

This international symposium aims to bring together experts and scholars from around the world to discuss the latest research findings of LHAASO and their corresponding implications in various aspects of astrophysics, including cosmic ray physics and multi-messenger astronomy. We hope that this symposium will foster academic exchange and collaboration, and deepen our understanding of the significance and importance of the LHAASO experiment in advancing our knowledge of  the universe.

 

The 2nd LHAASO symposium will be hosted by the Chinese University of Hong Kong at Hong Kong, China from March 20th to March 25th. On-site registration will begin on the March 20th, the main conference will take place from 21st to 24th, and the 25th is reserved for discussion.

Zoom link: 

https://cuhk.zoom.us/j/96796012422?pwd=k5fnT6s6ozvnBwmqa6ykNfPgLNbmnZ.1

Acknowledgements

We gratefully acknowledge the generous support provided by the Institute of Theoretical Physics, the Faculty of Science, and the CAS-ANSO Conference Program. Their contributions were instrumental in making this conference a success.

 

 

High-resolution version

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Speaker list

Felix Aharonian	Gwenael Giacinti	Enrico Peretti
Katsuaki Asano	Francis Halzen	Giada Peron
Maxim Barkov	Sergio  Hernández-Cadena	Tanguy Pierog
Pasquale Blasi	Shicong Hu	Sarah Recchia
Markus Boettcher	Tianqi Huang	Brian Reville
Niccolo Bucciantini	Susumu Inoue	Dmitri Semikoz
Zhen Cao	Kang Jia	Giorgia Sironi
Sabrina Casanova	Shigero Kimura	Andrew Taylor
Silvia Celli	Cong Li	Diego Torres
Songzhan Chen	Zhe Li	Jieshuang Wang
Silvia Crestan	Ruoyu Liu	Kai Wang
Roland Crocker	Lingling Ma	Sha Wu
Lixin Dai	Teshima Masahiro	Huirong Yan
Paolo Desiati	Alison Mitchell	Ruizhi Yang
Giuseppe Di Sciascio	Kaya Mori	Qiang Yuan
Ralph Engel	Giovanni Morlino	Chuan Yue
Carmelo Evoli	Igor Moskalenko	Min Zha
Yizhong Fan	Kohta Murase	Xiao Zhang
Hua Feng	Gor Oganesyan	Shoushan Zhang
Stefano Gabici	Giovanni Pareschi	Yi Zhang
		Heshou Zhang

LHAASO final poster.pdf

LHAASO symposium call.pdf

Thursday, 20 March

14:00 → 18:00 Registration

Friday, 21 March

08:00 → 08:30 Light breakfast

08:30 → 08:40 Welcome

Speaker: Zhen Cao (高能所)

08:40 → 10:25 Friday Morning A

Convener: Kenny Chun Yu Ng

08:40 A Review of LHAASO observation on cosmic ray source SNR

Speaker: Zhen Cao (高能所)

09:15 Galactic Cosmic Rays: General Review

Speaker: Gabici Stefano

gabicilhaaso.pdf

09:50 SNRs as CR accelerators

Speaker: Pasquale BLASI

HongKongLHAASO-Blasi.pdf

10:25 → 10:45 Coffee Break

10:45 → 12:30 Friday Morning B

Convener: Songzhan Chen

10:45 Star clusters as CR accelerators

Speaker: Giovanni Morlino

Morlino_LHAASO2025.pdf

11:20 Detection of Microquasars at ultra-high energies by LHAASO

Speaker: Cong Li (高能所)

LHAASO Symposium- Cong Li.pptx

11:55 Ultra-High Energy Phenomena in Hyper-Accreting Microquasars

I will discuss ultra-high-energy phenomena in microquasars and their
close environments, with a particular focus on compact binaries
characterized by super-Eddington accretion rates. The recent detection
of UHE gamma-ray halos from some of these objects could be a clue for
understanding the origin of galactic cosmic rays in the most problematic
part of the spectrum beyond the "knee" around a few PeV.

Speaker: Felix Aharonian (MPIK/DIAS)

FA_2ndLHAASO.pdf

12:30 → 14:00 Lunch Break

14:00 → 16:00 Friday Afternoon A

Convener: Zhe Li

14:00 Probing extreme particle acceleration in the SNR G106.3+2.7 region with LHAASO

Speaker: WU Sha (高能所)

14:20 LHAASO observation towards the young supernova remnants Cas A and Tycho

Speaker: Xiao ZHANG (Nanjing Normal University)

2025_03_21_HK_LHAASO_xiao2.pdf

14:40 Using LHAASO data to constrain the presence of hadronic Cosmic Rays in pulsar environments

"In recent years, the advent of LHAASO has revealed a wealth of information about ultra high energy (UHE) gamma-ray sources within our galaxy. This potentially reveals the locations of galactic PeVatrons, powerful accelerators of hadronic cosmic rays. However, the most common physical association of UHE gamma-ray sources to date is with energetic pulsars, known to be predominantly leptonic sources.
In this contribution, I will outline some ways in which LHAASO data can be used to constrain the presence of hadronic Cosmic Rays in pulsar environments. Both spectral and morphological information can be utilised to constrain the fraction of particles likely to be hadrons and their potential origin.
A brief outlook will be given towards future observations and data required to further improve these constraints. "

Speaker: Alison MITCHELL

2025_LHAASO_symposium_AM.pdf

Crab_particle_reacceleration_WTS_time.gif

15:00 Interpreting the Galactic diffuse emission from GeV to PeV

The Galactic diffuse emission (GDE) contains the whole information about the bulk of Galactic cosmic rays which are injected into the ISM and then propagate through the disk. The detection of interstellar emission directly tells us about the spatial and spectral distribution of the cosmic rays far from Earth. The comparison of the emission derived from gamma-ray observations with the emission deduced from locally measured cosmic rays can clarify whether we live in a special place in terms of cosmic rays. The GDE however is contaminated with the emission of the numerous unresolved sources that populate the Disk and are too faint to be individually detected. At the same time, the uncertainties related to the nuclear cross section limit the precision of the predictions derived from local cosmic-ray measurements.

I will discuss how all these factors should be accounted for when evaluating the results from the GDE, and discuss new regions for analysis of GeV and PeV GDE. I will stress on the role of molecular clouds, in reducing the uncertainties related to unresolved sources and their detectability from GeV to PeV.

Speaker: Giada PERON

lhaaso_peron.pdf

15:20 Non-thermal emissions from the Galactic magnitized halo powered by Galactic outflows

The large-scale structures such as Fermi Bubbles and eROSITA Bubbles provide a unique opportunity to study our Milky Way. However, the nature and origin of these large structures are still under debate. In this talk, I will present the identification of several kpc-scale magnetised structures based on their polarized radio emission and their gamma-ray counterparts, which can be interpreted as the radiation of relativistic electrons in the Galactic magnetic halo. These non-thermal structures extend far above and below the Galactic plane and are spatially coincident with the thermal X-ray emission from the eROSITA Bubbles. The morphological consistency of these structures suggests a common origin, which can be sustained by Galactic outflows driven by the active star-forming regions located at 3 − 5 kpc from the Galactic Centre. These results reveal how X-ray-emitting and magnetised halos of spiral galaxies can be related to intense star formation activities and suggest that the X-shaped coherent magnetic structures observed in their halos can stem from galaxy outflows.

Speaker: Heshou Zhang

HeshouZhang_v2.pdf

15:40 Galactic center and large scale diffuse X-ray emission

Observations in the X-ray band provide a powerful tool for investigating the origin of ultra-high-energy sources, offering crucial insights into the synchrotron radiation these sources produce. In this review, I will highlight recent advancements in our understanding achieved through observations with the eROSITA telescope, focusing on its contributions to the study of large-scale diffuse X-ray emission and the constraints it has placed on the X-ray properties of ultra-high-energy sources. Furthermore, I will focus on the X-ray emission from the central degree of the Milky Way, examining its various components and exploring potential counterparts of very-high-energy sources in the Galactic center region.

Speaker: G. Ponti

Ponti-LHAASO_2.pdf

16:00 → 16:20 Coffee Break

16:20 → 18:20 Friday Afternoon B

Convener: Shicong Hu

16:20 TeV-PeV gamma-ray emissions from Galactic Stellar-mass Black Holes

Galactic stellar-mass black holes, both isolated black holes and black holes in binaries, are proposed as Galactic PeVatron candidates. Recent discovery of TeV-PeV gamma-rays from micro-quasars by LHAASO strengthens the scenarios of micro-quasars as PeVatrons, but the origin of gamma-ray emissions are unknown. LHAASO also discovered mysterious “dark” sources that do not exhibit counterparts in lower-energy gamma-rays, the origin of which is unknown. In this talk, I will talk about our modeling of gamma-ray emissions from magnetized accretion flows in LHAASO-detected micro-quasars. In addition, I would like to discuss isolated black holes wandering in molecular clouds as a potential origin of “dark” sources.

Speaker: Shigero KIMURA

ShigeoKimura_UHE_from_GalacticBH.pdf

16:40 PeV particles and multi-messenger radiation from super-Eddington accreting Galactic compact objects

Extreme accretion goes hand to hand with strong winds and outflows.
In particular, winds are observed to reach mildly relativistic velocities and develop bubble structures in
super-Eddington accreting stellar mass compact objects powering Ultra-Luminous X-ray Sources (ULXs).
I will present a model for particle acceleration and associated multi-messenger emission in the bubbles powered by ULXs.
I will particularly focus on the maximum energy available to protons in these systems and possible gamma-ray spectra.
I will eventually discuss an application of such a model in the context of SS 433, a Galactic source recently detected by LHAASO up to hundreds TeV.

Speaker: Enrico PERETTI

Peretti_LHAASO_Symp_2025.pdf

17:00 HAWC micro-quasars

Speaker: Sabrina CASANOVA

casanova_v2.pptx

17:20 Particle transport in magnetohydrodynamic turbulence

Speaker: Huirong Yan (D)

17:40 New Galactic Magnetic Field model and cosmic ray propagation

We constructed new model of large scale Galactic Magnetic Field. We have achieved several important improvements compared to previous approaches. Due to account of our location inside of the Local Bubble our model does not require introduction of striated fields. For the first time we showed that the Fan Region in outer Galaxy can be modelled as a Galactic-scale feature. We identify the GMF components responsible for deflections of ultra-high energy cosmic rays in various regions of the sky and discuss the uncertainties in modelling these components, as well as potential future improvements. For LHAASO energies we expect propagation of cosmic rays in halo follow the structure of large scale Galactic Magnetic Field, which produce strongly elongated gamma-ray images.

Speaker: Dmitri Semikoz (APC, Paris)

GMF_March2025_LHAASO_HK.pdf

18:00 Interpretation for Gamma-Ray Afterglows in GRB 221009A and GRB 240529A

"We present simulation results for the multiwavelength afterglow lightcurves in GRB 221009A and GRB 240529A
based our time-dependent numerical codes.
The famous BOAT GRB, GRB 221009A, has been interpreted by a very narrow jet and an additional jet component.
The required opening angle to reproduce the very early break in the TeV lightcurve is extremely small.
Here, we present an alternative model with a highly magnetized ejecta and a broken power-law CSM density profile.
Our model succeeds in reproducing the lightcurves with a reasonable jet opening angle.
GRB 240529A show a shallow decay X-ray lightcurve in spite of its large gamma-ray luminosity,
which is an exceptional behavior. This GRB afterglow accompanies GeV emission.
We also provide our model fitting for this GRB."

Speaker: Katsuaki Asano

香港25_asano_v2.pptx

18:30 → 19:30 Welcome Dinner

cuhk welcome pdf.pdf

Saturday, 22 March

08:00 → 08:30 Light breakfast

08:30 → 10:15 Saturday Morning A

Convener: Ruizhi Yang

08:30 Pulsar Wind Nebulae: haloes, jets and the problem of particle escape.

Pulsar and Pulsar Wind Nebulae are among the most interesting high-energy astrophysical sources, and they provide us with a unique laboratory where relativistic processes can be studied and characterised in high details. They rank among the most efficient particle accelerators in the universe. The recent discovery of jet-like misaligned features and extended TeV haloes around old PSR moving through the ISM, have raised interesting theoretical question on the confinement of accelerated particles, and their escape properties. I will discuss the role of PWNe as high-energy TeV to PeV sources, our current understanding of their dynamics and particle acceleration properties, in the light of both current and future gamma-ray observatory, as well as our current understanding of the origin and properties of these escaping flows.

Speaker: Niccolo Bucciantini

Bucciantini LHAASO_compressed.pdf

09:05 New Meaurements of PWNe and Pulsar Halos by LHAASO

Speaker: Ruoyu Liu

09:40 Gamma-ray Pulsars

Speaker: Diego Torres

Torres-LHASSO-Pulsars-gamma.pdf

10:15 → 10:45 Coffee Break

10:45 → 12:30 Saturday Morning B

Convener: Yi Zhang

10:45 Recent X-ray observations of Galactic PeVatrons

The recent discovery of over 40 ultra-high-energy (UHE; > 100 TeV) gamma-ray sources and neutrino emission in the Galactic Plane has provided strong evidence for the existence of Galactic PeVtrons, which are capable of accelerating particles to PeV energies. As demonstrated by previous studies of TeV gamma-ray sources, X-ray observations play a crucial role in identifying these extreme particle accelerators by detecting synchrotron emission from primary and secondary TeV-PeV electrons. In particular, a combination of broadband spectral energy distribution (SED) and morphological data in the X-ray and TeV bands serves as a powerful tool for probing their particle acceleration and emission mechanisms. This presentation will review the latest multi-wavelength studies of Galactic PeVatron candidates, primarily focusing on X-ray observations in conjunction with radio, GeV, and TeV data. I will highlight (1) multi-epoch NuSTAR hard X-ray observations of young supernova remnants, (2) multi-wavelength observations of pulsar wind nebulae associated with UHE sources, (3) X-ray investigations of new PeVatron classes (e.g., microquasar jets), (4) X-ray surveys of the Galactic Center, and (5) searches for X-ray counterparts of unidentified or dark Galactic PeVatrons. Finally, I will discuss the future prospects of X-ray astrophysics in advancing our understanding of Galactic PeVatrons.

Speaker: Kaya Mori

LHAASO_symposium_KMori.pdf

11:20 Galactic Cosmic Rays and Diffuse γ-ray and ν emission

Speaker: Igor Moskalenko

LHAASO_Moskalenko.pdf

11:55 Measurement of diffuse gamma-ray emission from Galactic plane with LHAASO

Speaker: Qiang Yuan

202503_LHAASO_Symposium_YuanQ.pdf

12:30 → 14:00 Lunch Break

14:00 → 16:15 Saturday Afternoon A

Convener: Min Zha

14:00 EP prospect for LHAASO sources

Speaker: Feng Hua

EP

14:35 TeV gamma-ray halos

"The detection of extended multi-TeV gamma ray halos around pulsars provides a unique tool to investigate the propagation of cosmic rays in the magnetized turbulent interstellar medium around sources.
Such emission has been analyzed in the framework of isotropic diffusion, invariably leading to infer a diffusion coefficient in the source region two-three orders of magnitude smaller than that typically found in models of Galactic cosmic ray transport. Attempts to explain such suppression and/or to reconcile it with typical diffusion coefficients, exploited a variety of effects, such as anisotropic diffusion and turbulence self-generation by the escaping particles, which however have problem in explaining the morphology, or the transition between ballistic and diffusive propagation, which can require an unrealistically large acceleration efficiency.
Here we provide an overview of the proposed scenarios, discussing the entailed theoretical advantages and diffuculties, and the implied observational signatures.
We also discuss how the high sensitivity and large FoV of LHAASO, combined with the superior
angular resolution of future IACTs, such as ASTRI Mini-Array and CTAO, may allow to distinguish such features and possibly lead to disentangle among the proposed transport models."

Speaker: Sarah Recchia

RECCHIA_LHAASO_2025.pdf

14:55 Galactic Center Pevatron Outflow

"Observations by HESS have indicated that the center of the galaxy harbors a hadronic
Pevatron accelerator. The subsequent propagation of these PeV particles accelerated are considered
in the framework of a Galactic center driven outflow. Non-thermal signatures from this outflow are
discussed."

Speaker: Andrew Taylor

Taylor_LHAASO_Symposium_Mar25.pdf

15:15 A giant ultra-high-energy γ-ray emitting region associated with a millisecond pulsar

Speaker: Zhe Li

15:35 LHAASO's measurement of PSR J1849-0001

Speaker: Kai Wang

15:55 Long-term Observation of UHE emission from Crab Nebula with LHAASO

Speaker: Songzhan Chen

chensongzhan-v1.pdf

chensongzhan-v1.pptx

16:15 → 16:35 Group Photo and Coffee Break

16:35 → 18:30 Saturday Afternoon B

Convener: Cong Li (高能所)

16:35 Acceleration of Comsic Rays

Speaker: Brian Reville

LHAASO_Symp25_Reville(1).pdf

17:10 The displaced TeV signal of globular cluster Terzan 5 and implications for CR transport

Terzan 5 is the most luminous Galactic globular cluster in the Fermi band. Uniquely amongst globular clusters, it also has an associated TeV band source (HESS Collaboration, 2011). Strangely, however, the centroid of this extended TeV source is appreciably offset from the cluster itself by about 8 pc. We show that this displacement is naturally explained by cosmic ray electrons accelerated in the bow shock around the cluster, which then propagate a finite distance down the magnetotail of the cluster before pitch-angle scattering processes re-orient enough of them towards Earth to produce a detectable γ-ray signal. The angular distance between the cluster and the signal places tight constraints on the scattering rate, which we show are consistent with a model in which scattering is primarily due to excitation of magnetic waves by the cosmic rays themselves. The analysis method we develop here will make it possible to use sources with similarly displaced non-thermal X-ray and TeV gamma-ray signals as direct probes of cosmic ray scattering across a range of Galactic environments.

Speaker: Roland Crocker

Crocker_ LHAASO_2_Hong_Kong_2025_v2.pdf

17:30 Some usually overlooked aspects in radiative and morphological modelling of pulsar wind nebulae

Speaker: Diego Torres

Torres-LHASSO-PWN_v2.pdf

17:50 Cosmic-ray propagation in the Galaxy: Insights from the diffuse emission and TeV halos

Gamma-ray observations provide important information on cosmic-ray (CR)
propagation in our Galaxy.
First, we present a new model of CR propagation in the Milky Way, where
CRs are injected at discrete transient sources in the disc. We then
calculate the corresponding diffuse Galactic gamma-ray emission. We find
that the diffuse gamma-ray emission at >~ 100 TeV is very clumpy, and
does not correlate with the gas density along the line of sight. It is
substantially different from the relatively smoother emission detected
by Fermi at ~ GeV energies. We also discuss how many (hadronic)
PeVatrons would be detectable in our simulations, and compare our
predictions with LHAASO data. We show that this allows to place
interesting constraints on CR transport in the Galaxy.
Second, we discuss detected TeV halos. We show that current gamma-ray
measurements place interesting constraints on the turbulent magnetic
fields around these pulsars, and we examine the implications for CR
transport. Also, we suggest that extended gamma-ray sources of a
hadronic origin should exist in the data. We show that such a source may
exist in the AS-gamma data at 398-1000 TeV. Observations of this new
type of sources could be used to constrain the Galactic magnetic field
geometry.

Speaker: Gwenael Giacinti

Giacinti_LHAASO_Symposium_2025.pdf

18:10 Deciphering the Knees in the Cosmic Ray Energy Spectrum after LHAASO measurements

Speaker: Carmelo Evoli (Gran Sasso Science Institute)

slides

Sunday, 23 March

08:00 → 08:30 Light breakfast

08:30 → 10:15 Sunday Morning A

Convener: Ruoyu Liu

08:30 A Review of LHAASO Measurements of Cosmic Ray Proton and Helium Energy Spectra in the Knee Region

Speaker: Shoushan Zhang

09:05 Extragalactic Cosmic Rays

Speaker: Ralph Engel

UHECR

09:40 Cosmic-ray spectra below the knee

Speaker: Yizhong Fan

Cosmic rays below the knee_HongKong2025_FAN.pdf

10:15 → 10:45 Coffee Break

10:45 → 12:30 Sunday Morning B

Convener: Qiang Yuan (PMO)

10:45 Hadronic Interaction Model

Speaker: Tanguy Pierog

Pierog_Had_Int_LHAASO_2025.pdf

11:20 Cosmic-ray anisotropy

Speaker: Paolo Desiati

Desiati - CR Anisotropy - 2nd LHAASO Symposium.pdf

Desiati - CR Anisotropy - 2nd LHAASO Symposium.pptx

PowerAngularSpectrum.gif

SkyMap.gif

11:55 Observation of Cosmic Ray Anisotropy by LHAASO

Speaker: Yi Zhang

12:30 → 14:00 Lunch Break

14:00 → 16:15 Sunday Afternoon A

Convener: Jian Li

14:00 Cosmic Ray Energy Spectrum, Composition, and Hadronic Interaction Model Tests in the Knee Region

Speaker: Lingling Ma

马玲玲-upload.pdf

14:35 Neutrons in EAS

Speaker: Ralph Engel

14:55 On the measurement of the elemental composition in the PeV energy region: a critical review

"A statistically significant detection of Cosmic Rays above about 100 TeV/n can be obtained only from ground operating detectors (arrays/telescopes).

The reconstruction of the primary characteristics (energy, mass, arrival direction) is carried out in an indirect way exploiting the detection of Extensive Air Showers.
Strictly speaking, no air shower experiment measures the primary composition of CRs. We exploit different mass-sensitive EAS observables.
But the sensitivity to the mass of these observables are different, in particular because they investigate different kinematic regions of the hadronic interaction undergone by the primary particle.

The results on the elemental composition in the PeV energy region are still conflicting and can be divided into 2 categories, those that find a knee of the light component below the PeV and those that find the knee of the protons at the same energy as the knee of the all particle energy spectrum.

In this talk we will show that, according to the results obtained by a number of experiments in the last decades, the reconstructed primary spectra of the different components seems to depend on the observed kinematic region of the hadronic interaction."

Speaker: Giuseppe DiSciascio

DiSciascio_LHAASO2025-Final.pdf

15:15 Study of hardronic interaction and spectral measurements of cosmic-ray nuclei with DAMPE space mission

Speaker: Chuan Yue

15:35 Super-Eddington Tidal Disruption Events as Cosmic Accelerators for High-Energy Cosmic Rays and Neutrinos

Speaker: Lixin Dai

LHASSO2025_Dai.pptx

15:55 Detection of Very-high-energy Gamma-ray Emission from the Radio Galaxy M87 with LHAASO

Speaker: Shicong Hu

LHAASO_M87_Hu.pdf

16:15 → 16:35 Coffee Break

16:35 → 18:35 Sunday Afternoon B

Convener: Dmitri Semikoz (APC, Paris)

16:35 Probing circumgalactic cosmic rays and their sources around the Milky Way

Cosmic ray (CR) hadrons with GeV-PeV energies are expected to reside in the circumgalactic medium (CGM) around the Milky Way (MW), having escaped from the Galactic disk, or injected in situ by satellite galaxies, large scale shocks due to Galactic winds, etc. In some cases, circumgalactic CRs (CGCRs) may play important thermal and dynamical roles in the evolution of galaxies, but observational evidence for them is very scarce to date. We discuss the various advantages of PeV gamma rays for probing CGCRs, by virtue of gamma-gamma absorption with the cosmic microwave background. Recent observations of the MW CGM suggest that the cool, highly structured gas traced by intermediate-velocity clouds (IVCs) and high-velocity clouds (HVCs) is comparable to the hot gas in total mass, implying that gamma-ray and neutrino emission from the MW CGM can be significantly anisotropic. Using data from Tibet ASγ, we search for signals associated with IVCs and HVCs, and find no clear evidence so far. We discuss the implications for the origin and propagation of CRs around the MW, expectations for LHAASO, and the relation to high-energy neutrinos observed by IceCube. The prospects for future Southern facilities such as ALPACA and SWGO are also discussed.

Speaker: Susumu Inoue

SInoue_MWCGCR-LHAASO25.pdf

16:55 Multimessenger Implications of High-Energy Neutrino and Gamma-Ray Backgrounds

Speaker: Kohta Murase

LHAASO2025_murase.pdf

17:15 Acceleration of galactic cosmic rays.

Speaker: Siming Liu (Southwest Jiaotong University)

1_ACC2025liu.pdf

17:35 Origins and Acceleration of Very- and Ultra-High-Energy Cosmic Rays

The origin of cosmic rays (CRs) remains an open question. The CR spectrum is characterized by two main breaks: the knee at ~3 PeV (1e15 eV) and the ankle at ~3 EeV (1e18 eV). It is widely accepted that ultra-high-energy cosmic rays (UHECRs) above the ankle originate from extragalactic sources, with the transition energy between galactic and extragalactic components lying between the knee and the ankle. Recent observations suggest that the proton cutoff for UHECRs occurs at a few EeV, while higher energy CRs consist of higher mass atomic nuclei. Centaurus A, a nearby radio galaxy, is considered a major source of UHECR anisotropies, supporting the idea that radio galaxies (active galactic nuclei with kpc-scale jets) are sources of UHECRs. In this talk, I will present our analytical and numerical study using relativistic magnetohydrodynamic and particle-in-cell (RMHD-PIC) simulations of astrophysical jets. This study provides a self-consistent framework for understanding multi-wavelength observations and the acceleration of UHECRs. Furthermore, similar acceleration can take place in galactic ultra-luminous X-ray sources (ULXs), which can contribute to the CR flux between the knee and the ankle.

Speaker: Jieshuang Wang

JSW-LHAASO-Symposium.pdf

17:55 Magnetar-like flares behind the high-energy emission in LS 5039

Speaker: Maxim Barkov

Barkov

18:15 Constraints on ultraheavy dark matter properties from dwarf spheroidal galaxies with LHAASO observations

Speaker: Kang Jia

KangJia_DM_Hongkong2025.pdf

18:35 → 21:00 Banquet

Bus starts leaving 6:50pm, 7:10pm at the latest.

banquet.pdf

Monday, 24 March

08:00 → 08:30 Light breakfast

08:30 → 10:15 Monday Morning A

Convener: Zhen Cao (高能所)

08:30 IceCube: The First Decade of Neutrino Astronomy

"The discovery of an unexpectedly large flux of extragalactic neutrinos
revealed that cosmic neutrinos are produced in environments from which
accompanying gamma rays from neutral pion decay escape with significant
loss of energy, to appear below the threshold of the NASA Fermi gamma
ray satellite. IceCube also isolated a flux of neutrinos from our own Galaxy,
which is not a dominant feature of the neutrino sky unlike what is observed
for all wavelength of light. Cosmic ray accelerators must exist in other
galaxies that are not present in our own, possibly the active supermassive
black hole. The discovery of the galaxy NGC 1068 and other such sources
confirmed the scenario where neutrinos are indeed produced in the dense
gamma-ray obscured cores of active galaxies. Finally, we speculate that
similar neutrino processes are characteristic of the accreting black holes in
Galactic X-ray binaries, despite of their different masses and physical
sizes."

Speaker: Francis Halzen

LHAASO2025_Halzen.pdf

pptx

09:05 Gamma Ray Emitting AGN

Speaker: Markus Boettcher

VHE_AGN_LHAASO_Symposium2025_Boettcher.pptx

09:40 Detection of Extragalactic Sources and Transients from LHAASO-WCDA

Speaker: Min Zha

10:15 → 10:45 Coffee Break

10:45 → 12:30 Monday Morning B

Convener: Hao Zhou (Shanghai Jiao Tong University)

10:45 Gravitational waves and GRBs

"Gamma-ray bursts are short-lasting MeV transients of extragalactic origin. In the last
decades we have learnt about two channels of GRB production: collapsars and compact
binary coalescence. The merger-driven GRBs are also accompanied with gravitational
waves (GWs), thus they offer a unique laboratory for high energy astrophysics, cosmology and fundamental
physics. In this talk I will discuss the current status of GRB observations and open problems.
Then I will talk about the prospects of joint GW and GRB detection in light of next generation
gravitational wave interferometers and upcoming electromagnetic facilities. "

Speaker: Gor Oganesyan

Gor_Oganesyan_LHAASO_symposium.pdf

11:20 CTA status and highlights

Speaker: Teshima Masahiro

2025_0323_CTAO.pdf

11:55 HAWC status

Speaker: Sergio Hernández Cadena

lhaasoSymposium_2025_hawc_novid.pdf

12:30 → 14:00 Lunch Break

14:00 → 16:20 Monday Afternoon A

Convener: Roland Crocker

14:00 First observation of an UHE neutrino event with KM3NeT

Speaker: Silvia Celli

Talk_LHAASO2025_KM3NeT_CelliSilvia.pdf

14:25 Astri status

Speaker: Giovanni Pareschi

Giovanni_Pareschi_ASTRI_LHAASO2025_NEW.pdf

Powerpoint Version

15:00 From ASTRI-Horn to ASTRI-1: Advancing the ASTRI Project

The ASTRI Project, led by the Italian National Institute for Astrophysics (INAF), is
developing a nine-telescope array for very high-energy gamma-ray astronomy in the
1–200 TeV range, known as the ASTRI Mini-Array, which is currently being installed at
the Teide Observatory in Tenerife. A key milestone was the ASTRI-Horn telescope, a
prototype of a compact aplanatic dual-mirror imaging atmospheric Cherenkov telescope
(4 m diameter), pioneered the Schwarzschild-Couder optical design for Cherenkov
observations. With its 8° wide field of view (FoV), high angular resolution, and nearly
uniform sensitivity across the entire FoV, ASTRI-Horn successfully detected the Crab
Nebula in 2018. After a major refurbishment (2020–2022), it has been extensively used
for gamma-ray and cosmic-ray studies. Recent observations (2022–2024) have provided
essential inputs to the ASTRI Mini-Array, particularly in validating the data analysis pipeline.

The first ASTRI Mini-Array telescope, ASTRI-1, started the commissioning phase in
November 2024 and is now fully operational. Maintaining the same innovative optical
design, large FoV (10°), and high angular resolution, ASTRI-1 has already delivered
promising results from systematic observations of the Crab Nebula, accumulating
hundreds hours of data under different sky illumination conditions and zenith angles. In
this contribution, we highlight the ASTRI-1 key performance characteristics obtained
during commissioning phase, providing a first assessment of its capabilities and laying
the groundwork for the scientific exploitation of the full Mini-Array.

Speaker: Silvia Crestan

Crestan_From_ASTRI-Horn_to_ASTRI-1.pdf

15:20 From ASTRI to CTA-SST: the ASTRI heritage in CTAO

The CTAO (Cherenkov Telescope Array Observatory) is working to establish itself as the largest gamma-ray
astronomy observatory through a network of imaging atmospheric Cherenkov telescopes distributed across two sites. The North site already has operational telescopes, while the South site is set to commence installation within the next year. This ambitious project
is driven by a large international collaboration, with Italy at the forefront of developing the Small Size Telescope (SST), which is based on the ASTRI design. The talk mentioned provides an overview of the ASTRI heritage in the context of CTA and updates
on the status of the SST.

Speaker: Giorgia Sironi

2025_LHAASO_Sironi.pdf

15:40 LACT project: status and prospects

Speaker: Ruizhi Yang

LACT_status.pptx

16:00 Current Progress and Future Prospects of the HUNT Project

Speaker: Huang Tianqi

HUNT_LHAASO2025.pptx

16:20 → 16:40 Closing Remarks

Speaker: Felix Aharonian (MPIK/DIAS)

16:40 → 18:00 Monday Afternoon B: Discussion

Tuesday, 25 March

09:00 → 14:00 Excursion and discussion