Kavli Affiliate: Gordan Krnjaic | Summary:We propose a novel cosmological scenario in which baryonic neutron stars could plausibly form in the early universe. If baryogenesis initially produces an excessively-large baryon asymmetry, $Y_B gg 10^-10,$ the baryonic mass inside the horizon can exceed the minimum neutron star mass before big bang nucleosynthesis (BBN). While this large […]
Kavli Affiliate: Thomas Crawford | Summary:Recent cosmological data reveal tension between parameters inferred from measurements of the cosmic microwave background (CMB), baryon acoustic oscillations (BAO), and supernovae (SN) under $Λ$CDM. Typical dynamical dark energy parameterizations (such as $w_0w_a$) that seek to jointly resolve these tensions have an equation of state parameter that crosses into the […]
Kavli Affiliate: Satoshi Shirai | Summary:We study the impact of multiple vector-like fermions in SU(5) grand unified theory (GUT). Threshold effects from extra fermions allow the observed gauge couplings to be consistently matched to a single unified gauge coupling, and typically raise the unification scale to $M_mathrmGUTsimeq 10^15.5,mathrmGeV$. Because the Standard Model fermions arise as […]
Kavli Affiliate: Misao Sasaki | Summary:The pulsar timing array (PTA) is a powerful technique for detecting nanohertz gravitational wave backgrounds (GWBs). However, conventional PTAs lack sensitivity to parity violation in the GWB. In this work, we propose a dipole pulsar timing array system (dPTA). By deriving the overlap reduction functions (ORFs) from the cross-correlation of […]
Kavli Affiliate: Lijing Shao | Summary:The dense environment of our Galactic Center (GC) offers a unique laboratory for probing ultralight dark matter (ULDM). We explore the prospect of detecting a scalar ULDM field through its effects on the orbital dynamics of S-stars around the supermassive black hole in the GC, Sgr A$^*$. We consider both […]
Kavli Affiliate: Andrew Vanderburg | Summary:Wide-orbit ($>$10 AU) gas giant planets shape the architecture of planetary systems, yet their occurrence rate remains poorly constrained. JWST has obtained the deepest mid-infrared images of nearby stars to date through substantial MIRI time-series observations of transiting planets, providing sensitive probes for wide-orbit companions. Here we leverage 15 micron […]
Kavli Affiliate: George Ricker | Summary:Photometric missions such as Kepler and TESS have generated millions of light curves covering almost the entire sky, offering unprecedented opportunities to study stellar variability and advance our understanding of the Universe. In this data-rich environment, machine learning has emerged as a powerful tool to efficiently and accurately process and […]
Kavli Affiliate: Roberto Maiolino | Summary:Little Red Dots (LRDs) have emerged as a key population linked to early black hole growth, yet photometric selections have predominantly targeted only the most extreme red systems, thereby shaping our current understanding of this new population of objects. In this work, we deliberately explore a broad range of optical […]
Kavli Affiliate: Roberto Maiolino | Summary:We present a JWST/NIRSpec-IFU study of metallicity gradients in seven low-metallicity systems at $z=7.2-9.5$. The main sample spans stellar masses of $rm log(M_*/M_odot) sim 7.8-9.5$, star formation rates (SFRs) of $rm log(textSFR / M_odot textyr^-1) sim 0.5-2.5$, and gas-phase metallicities of $4%-15 %~Z_odot$. Within our sample, we also identify three […]
Kavli Affiliate: Kohei Inayoshi | Summary:The orbital decay of binary systems is a critical process for understanding the evolution of massive binary black holes (MBBHs) and binary star formation. Performing high-resolution three-dimensional magnetohydrodynamic (MHD) simulations, we investigate a binary system that accretes gas from an infalling envelope analogous to the collapse of molecular clouds in […]