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: 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 […]

Kavli Affiliate: Andrew Vanderburg | Summary:Young planets (<1 Gyr) provide opportunities to directly probe planet formation and evolution processes in action. However, due to heightened stellar activity, there is a lack of known transiting planets in adolescence (~100-500 Myr). Here we present the validation of TIC 150070085 b, a 3.6 R_E planet on a 10.47 […]

Kavli Affiliate: Max Tegmark | Summary:The increasing situational awareness of language models raises safety concerns: models might be aware when they are evaluated, and adjust their behavior to evade monitoring and resist modification, e.g., pretending to be aligned only in evaluation. This alignment faking behavior is often interpreted as scheming: an intentional effort of strategic […]