Kavli Affiliate: Michael Fausnaugh | Summary:The Luminous Fast Blue Optical Transient (LFBOT) AT2022tsd exhibited minutes-timescale optical flares in the tens of days following the initial transient event, likely due to a central engine — either an accreting black hole or a magnetar. In this paper, we use data from the Transiting Exoplanet Survey Satellite (TESS) […]

Kavli Affiliate: Lina Necib | Summary:Understanding how galaxies like the Milky Way assembled over cosmic time remains a central question in astrophysics. Understanding the processes that shaped their formation and evolution is greatly enhanced by the joint use of observational data and high-resolution cosmological simulations. Old stars in the inner regions of galaxies serve as […]

Kavli Affiliate: Mark Vogelsberger | Summary:Understanding the sources and evolution of cosmic reionization remains a central challenge in astrophysics, with the escape of ionizing Lyman-continuum (LyC) photons from early galaxies representing a major uncertainty. In this work, we use more than 35,000 galaxy realisations from the THESAN-ZOOM cosmological radiation-hydrodynamic simulations to identify indirect diagnostics of […]

Kavli Affiliate: Mark Vogelsberger | Summary:The JWST discoveries of supermassive black holes (BHs) at $z gtrsim 5$ may provide key insights into their seeding origins. Using new $[18-72~rm Mpc]^3$ BRAHMA cosmological simulations, we investigate how variations in heavy-seed prescriptions, coupled with a subgrid dynamical friction model, shape BH populations at $z sim 5$ and $z […]

Kavli Affiliate: Anna Frebel | Summary:Carbon-enhanced metal-poor (CEMP; with $rm[Fe/H] le -2.0$ and $rm[C/Fe] ge 0.7$) stars preserve information about early chemical enrichment, low-mass star formation, and the hierarchical assembly of galaxies. In this study, we have compiled an extensive literature sample of 1032 stellar carbon abundances spanning the metal-poor Milky Way halo (437 stars), […]

Kavli Affiliate: Salvatore Vitale | Summary:The distribution of the effective inspiral spin ($χ_mathrmeff$) of the binary black holes detected by LIGO-Virgo-KAGRA can shed light on their formation pathways. We analyze the GWTC-5.0 dataset with two models-one flexible, one fully parametric-that jointly describe $χ_mathrmeff$ and primary mass. We clarify that the previously-reported skewness in the $χ_mathrmeff$ […]

Kavli Affiliate: Salvatore Vitale | Summary:The distribution of the effective inspiral spin ($χ_mathrmeff$) of the binary black holes detected by LIGO-Virgo-KAGRA can shed light on their formation pathways. We analyze the GWTC-5.0 dataset with two models-one flexible, one fully parametric-that jointly describe $χ_mathrmeff$ and primary mass. We clarify that the previously-reported skewness in the $χ_mathrmeff$ […]

Kavli Affiliate: Nathan P. Lourie | Summary:In March 2026, the Einstein Probe (EP) discovered its most nearby (z = 0.0343) Fast X-ray Transient (FXT), EP260321a, the first EP FXT to provide a strong match to expectations for X-ray ”shock breakout” (SBO) emission. Here, we present our multi-wavelength follow-up campaign of EP260321a and its broad-line Type […]

Kavli Affiliate: Dheeraj Pasham | Summary:The explosion of a star is first marked by the shock wave breaking out of the stellar surface, producing a burst of ultraviolet and X-ray radiation. These events are observationally rare, despite likely accompanying the majority of supernovae. Here, we report on our multi-wavelength observing campaign of the closest Einstein […]

Kavli Affiliate: Dheeraj Pasham | Summary:The explosion of a star is first marked by the shock wave breaking out of the stellar surface, producing a burst of ultraviolet and X-ray radiation. These events are observationally rare, despite likely accompanying the majority of supernovae. Here, we report on our multi-wavelength observing campaign of the closest Einstein […]