Kavli Affiliate: Feng Long| Summary: We develop an adaptive jump test for discretely observed high-frequency semimartingales by combining the A"it-Sahalia–Jacod ratio statistic (A"it-Sahalia and Jacod, 2009) and the Lee–Mykland extreme-return statistic (Lee and Mykland, 2008) with the Cauchy combination rule. Allowing stochastic It^o drift, volatility, and leverage, we show asymptotic independence under the continuous-path null […]
Kavli Affiliate: Feng Long| Summary: We develop an adaptive jump test for discretely observed high-frequency semimartingales by combining the A"it-Sahalia–Jacod ratio statistic (A"it-Sahalia and Jacod, 2009) and the Lee–Mykland extreme-return statistic (Lee and Mykland, 2008) with the Cauchy combination rule. Allowing stochastic It^o drift, volatility, and leverage, we show asymptotic independence under the continuous-path null […]
Kavli Affiliate: Huawei Zhang | Summary:Metal-poor stars are crucially important for understanding the early Galaxy, first stars, and the Universe. In this series of papers, we present a homogeneous non-local thermodynamic equilibrium (NLTE) abundances analysis of 12 elements for 103 very/extremely metal-poor (VMP/EMP) stars with metallicity down to $-4.3$ dex. The sample was selected from […]
Kavli Affiliate: Huawei Zhang | Summary:Metal-poor stars are crucially important for understanding the early Galaxy, first stars, and the Universe. In this series of papers, we present a homogeneous non-local thermodynamic equilibrium (NLTE) abundances analysis of 12 elements for 103 very/extremely metal-poor (VMP/EMP) stars with metallicity down to $-4.3$ dex. The sample was selected from […]
Kavli Affiliate: Claudio Ricci | Summary:Red quasars (rQSOs) have been recognized as a short-lived, early stage in the evolutionary cycle of Active Galactic Nuclei (AGN), with fundamental differences in their intrinsic properties compared to blue quasars (bQSOs). In this work, we present the first large X-ray sample of 380 rQSOs, selected from the eROSITA/SDSS-V collaboration, […]
Kavli Affiliate: Claudio Ricci | Summary:The origin of high-energy astrophysical neutrinos remains a key open question in multimessenger astrophysics. A correlation between unabsorbed hard X-ray emission and high-energy neutrino luminosity has been reported in a sample of six active galactic nuclei with the highest individual IceCube significances, linking neutrino production to compact, photon-rich environments near […]
Kavli Affiliate: Claudio Ricci | Summary:The origin of high-energy astrophysical neutrinos remains a key open question in multimessenger astrophysics. A correlation between unabsorbed hard X-ray and high-energy neutrino luminosity has been reported in six active galactic nuclei with the highest individual IceCube significances, linking neutrino production to compact, photon-rich environments near supermassive black holes. We […]
Kavli Affiliate: Claudio Ricci | Summary:A tight correlation between nuclear millimeter (mm) and X-ray emission has recently been found in nearby ($z < 0.01$) and low-Eddington ratio ($rm λ_Edd < 0.1$) radio-quiet (RQ) Active Galactic Nuclei (AGN), suggesting a common origin in the hot X-ray corona. We test this relation in nine more distant RQ […]
Kavli Affiliate: Claudio Ricci | Summary:A tight correlation between nuclear millimeter and X-ray emission has recently been found in nearby ($z < 0.01$) and low-Eddington ratio ($rm λ_Edd < 0.1$) radio-quiet Active Galactic Nuclei (AGN), suggesting a common origin in the hot X-ray corona. We test this relation in nine more distant RQ AGN ($z […]
Kavli Affiliate: Linhua Jiang | Summary:We present a multi-wavelength physical characterization of 14 luminous Ly$α$ emitters (LAEs) at $zapprox6$, integrating deep ground-based Magellan/M2FS spectroscopy with heterogeneous JWST/NIRCam broad- and medium-band imaging. Identified via strong Ly$α$ lines with extreme Ly$α$ luminosities of $>10^42.6$ erg s$^-1$, the sample exhibits very large rest-frame equivalent widths ($gtrsim100$ Å) and […]