Axions and other Weakly Interacting Sub-eV Particles (WISPs) are compelling candidates for physics beyond the Standard Model, offering solutions to the strong-CP problem and viable dark matter components. Astrophysical X-ray observations provide a powerful and complementary approach to searching for these particles through their conversion into photons in large-scale magnetic fields.Using data from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), we pursue multiple strategies for axion detection. We search for axion–photon conversion in the Sun’s atmospheric magnetic field during the 2020 solar minimum, and for axion production via the nuclear M1 transition of 57Fe in the cores of nearby supergiant stars such as Betelgeuse. In addition, NuSTAR observations of Betelgeuse, following the work of Gianotti et al., probe axion production through the Primakoff process and axion–electron interactions, providing sensitivity to axion–photon, axion–nucleon, and axion–electron couplings. These studies yield the most stringent astrophysical constraints to date, improving previous solar and stellar limits by up to 1–1.5 orders of magnitude. Looking ahead, wide-field X-ray surveys such as eROSITA, with improved effective area and a complementary energy range, offer strong potential to further extend astrophysical axion searches across a broad range of masses and couplings. Together with laboratory experiments such as CAST and the forthcoming IAXO, these results underscore the growing role of X-ray astronomy in probing axions, WISPs, and the dark sector.

We have known for decades that magnetic fields and relativistic particles (cosmic rays) can play a key role in some astrophysical environments. But it has only recently become possible to model these directly including other key physics (like radiative cooling, self-gravity, star formation, etc.) in models of galaxies and super-massive black hole growth and “feedback.” Moreover those simulations have historically been limited to a very narrow dynamic range of scales being probed. I’ll discuss how a combination of new physics and new numerical methods has led to breakthroughs that now allow us to simulate problems like supermassive black hole growth, star and galaxy formation with truly unprecedented dynamic range reaching from the horizon to the intergalactic medium. These have revealed some major surprises. In particular, non-thermal physics may be vastly more important on both the smallest and largest scales, compared to previous assumptions. I’ll show how these simulations predict qualitatively new forms of strongly-magnetized accretion disks around supermassive black holes, that can resolve many decades-old observational puzzles and make new unique observational predictions. At the same time, the feedback from supernovae and black holes could be, on the largest (circum and intergalactic medium) scales dominated by cosmic rays. I’ll show how recent new observations of X-rays and the Sunyaev-Zeldovich effect, in particular, appear to be indicating that most of the pressure on these scales is not — as assumed in almost all models for decades — primarily thermal, but appears to be coming from cosmic rays. And I’ll show how new observations can probe this further over a range of galaxy mass scales.

Unraveling the planet formation process and the origin of the diversity of planetary systems require a comprehensive understanding of the planet-forming disks surrounding young stars. ALMA’s unprecedented spatial resolution and sensitivity have enabled a detailed examination of the physical and chemical structures of planet-forming disks (at ~10 au scale). The detections of gaps and rings in numerous disks have transformed our understanding of disk evolution and planet formation. I will first provide a summary on the detection and characterization of disk substructures, and discuss the exciting avenue of young planet search as guided by these disk features. While ALMA excels in probing the bulk disk property, the very innermost disk (within 1-3 au), remains elusive to its capabilities, which can now be well studied with JWST. In the second half of the talk, I will touch upon our expanding view of the inner disk chemistry, especially the interplay with substructures at large disk radii and for disks around very low-mass stars. By leveraging the capabilities of ALMA and JWST, we aim at establishing a global view of disk evolution, laying the groundwork for the development of a robust predictive model of planet formation.  

Bio: Feng Long is an Assistant Professor at the Kavli Institute for Astronomy and Astrophysics of Peking University. After receiving her PhD from Peking University in 2019, she spent three years as an SMA Postdoc Fellow at the Center for Astrophysics | Harvard & Smithsonian. From 2022 to 2025, she worked at the University of Arizona as a NASA Sagan Fellow. Her research uses advanced facilities like ALMA and JWST to study protoplanetary disk evolution and planet formation. 

The recently launched XRISM (JAXA/NASA/ESA) observatory has provided long-awaited high-resolution spectra of extended X-ray sources, including clusters of galaxies. These spectra enable direct measurements of gas kinematics in the intracluster medium (ICM). I will present XRISM results from observations of well-known bright galaxy clusters and discuss their implications for the physics of AGN feedback, ICM turbulence, cluster mergers and their assembly history, and cluster mass measurements for cosmology. Finally, I will compare these measurements with cosmological simulations, highlighting both what they reproduce and remaining challenges.

Thanks to the Hubble Space Telescope, combined with major ground-based facilities and gravitational lensing (“cosmic telescopes”), we have entered an era in which stellar clusters can be identified at cosmological distances. The James Webb Space Telescope (JWST) is now transforming this field -- and, more broadly, our view of the early Universe. With its exceptional sensitivity and angular resolution at infrared wavelengths, JWST, when coupled to strong gravitational lensing, can isolate individual star clusters even within the first half 0.5 Gyr of cosmic history. This lensing-enhanced spatial contrast enables the identification of candidate progenitors of present-day globular clusters and places them in the context of key questions, from the sources of ionizing photons during reionization to the emergence of extremely metal-poor (possibly near-pristine) star formation, and the possible connection to black-hole seeds. Looking ahead, ground-based facilities in the 2030s equipped with extreme adaptive optics (AO) -- most notably the ELT -- will consolidate these studies and push to even finer physical scales. The synergy between space and ground-based facilities will thus open an unprecedented window on the earliest stellar systems, connecting parsec-scale star formation to the assembly of galaxies and black holes in the reionization era.

James Webb Space Telescope (JWST) has opened a new window into the early universe, enabling sensitive, high-resolution images of the near-infrared sky and spectroscopy of faint, distant sources. The JWST Advanced Deep Extragalactic Survey (JADES) is a collaboration of the NIRCam and NIRSpec GTO teams pooling over 750 hours of JWST time to conduct an ambitious study of galaxy evolution in the Great Observatories Origins Deep Survey GOODS-South and GOODS-North fields. I will discuss exciting results from JADES observations about discoveries in the distant (z>12!) universe that provide new insight into the process of early galaxy formation and cosmic reionization. We discuss how our new constraints on star formation and galaxy growth at the very earliest times are rewriting the story of how the first galaxies form and evolve.