Kavli Affiliate: Feng Long| Summary: We consider estimation of high-dimensional long-run covariance matrices for time series with nonconstant means, a setting in which conventional estimators can be severely biased. To address this difficulty, we propose a difference-based initial estimator that is robust to a broad class of mean variations, and combine it with hard thresholding, […]
Kavli Affiliate: Luis Ho | Summary:We present multi-frequency polarimetric observations of 3C 84 obtained with the Korean VLBI Network at 43-141 GHz, the Very Long Baseline Array at 43 GHz, and the High Sensitivity Array at 8 GHz from 2015 to 2024. We find that the Faraday rotation measure (RM) decreases systematically with distance from […]
Kavli Affiliate: Renxin Xu | Summary:Strong nuggets with a baryon number of $Asim 10^10-30$ could be able to survive from the cosmic separation of the QCD phases, provided the transition from strange quark matter to strangeon matter is accounted for, thereby evading evaporation in the early Universe. Such strangeon nuggets may serve as a dark […]
Kavli Affiliate: Claudio Ricci | Summary:We present neutral atomic hydrogen (HI) imaging observations of 22 HI-rich ($M_rm HI gtrsim 10^9.7 M_odot$), hard X-ray-selected local Seyferts to explore how cool gas is supplied to active galactic nuclei (AGN) hosts. The sample predominantly resides in group-like, gas-rich environments. About 80% (18/22) of the galaxies have HI-detected neighbors, […]
Kavli Affiliate: Luis Ho | Summary:The clustering of galaxies encodes key information about the structure and assembly history of their host dark matter (DM) haloes, providing a powerful probe of the origin of extreme high-redshift systems. While halo assembly bias has been extensively studied at low redshift, its behavior in the early Universe remains poorly […]
Kavli Affiliate: Yingjie Peng | Summary:The Universe is now extensively populated by discy galaxies with coherent galaxy-wise stellar rotation. This disc prevalence has been deemed a late-time phenomenon because the penetrating cold gaseous streams in the early Universe ($zgtrsim 2$) fuel the star formation in galaxies too intensively to allow for thin disc formation. However, […]
Kavli Affiliate: Renxin Xu | Summary:Photosphere radius expansion (PRE) bursts provide a crucial tool for constraining the mass and radius of neutron stars. In this study, we analyze time-resolved spectroscopic data from XTE J1810-189 in 2008, which exhibit evidence of a PRE event. We report here the possibility of a small-size and low-mass neutron star […]
Kavli Affiliate: Huawei Zhang | Summary:The extent of envelope stripping in the progenitor stars is directly reflected in the diversity of spectral features observed in stripped-envelope supernovae (SESNe). Through extensive spectral observation and analysis, we aim to clarify the statistical differences between the subclasses of SESNe. The Tsinghua Supernova group obtained 249 optical spectra of […]
Kavli Affiliate: Claudio Ricci | Summary:We present the first spatially resolved kinematic evidence for dust in the outflows of Active Galactic Nuclei (AGN). We utilise observations from JWST with NIRSpec IFU and MIRI MRS data of 10 local Seyferts and use Principal Component Analysis (PCA) tomography to extract the kinematics of Polycyclic Aromatic Hydrocarbon (PAH) […]
Kavli Affiliate: Claudio Ricci | Summary:We present the first spatially resolved kinematic evidence for dust in the outflows of Active Galactic Nuclei (AGN). We utilise observations from JWST with NIRSpec IFU and MIRI MRS data of 10 local Seyferts and use Principal Component Analysis (PCA) tomography to extract the kinematics of Polycyclic Aromatic Hydrocarbon (PAH) […]