Using James Webb Space Telescope /NIRCam data over a 0.28 deg(2 )area from COSMOS-Web survey, together with Hubble Space Telescope /Advanced Camera for Surveys data, we investigate early-type fraction of massive galaxies with M-star > 10(10.5) M-circle dot at 0.2 < z < 2.0, and explore the formation of their early-type morphology. We measure concentration index C (= R-80 /R-20 ) and asymmetry index A , and select early-type galaxies with C > C-n=2.5 and A(cor) < 0 . 2 . Here, C-n=2.5 is the concentration expected for a S & eacute;rsic profile with n = 2 . 5 under the spatial resolution and depth of the data, and A(cor) is the asymmetry corrected for resolution effects. The fraction of early-type galaxies with M-star > 10(11) M-circle dot (= 10(10.5)-10(11) M-circle dot) decreases with increasing redshift from similar to 70 per cent (similar to 40-60 per cent) at z similar to 0.3 to similar to 20-25 per cent (similar to 15-25 per cent) at z similar to 1.8. We also examine the evolution of their R-20 and R-80 , which enclose 20 per cent and 80 per cent of the total flux of the galaxy, respectively. The median R-80 shows strong mass dependence and significant redshift evolution, whereas the median R-20 shows little dependence on either stellar mass or redshift. In contrast, morphological differences are more pronounced in R-20 than in R-80 : the median R 20 of early-type galaxies is smaller than that of late-type and irregular galaxies by 0.25-0.45 and 0.3-0.6 dex, respectively. The median SSFR (specific star formation rate) of sample galaxies strongly correlates with R-20 , and early-type galaxies have lower SSFRs by similar to 1 dex. We further find that early-type galaxies at z greater than or similar to 1 . 3 have younger mass-weighted stellar ages of t(mw) less than or similar to 2 Gyr than late-type and irregular ones. Their SSFRs, t(mw), and morphological properties suggest that these high-z early-type galaxies experienced rapid formation of a dense stellar core through starburst, followed by quenching of star formation, and subsequently resumed star formation similar to 1-2 Gyr later.
Marine heatwaves (MHWs) are characterized by extremely high water temperatures persisting for at least several consecutive days, and their severe ecological and economic impacts have been increasing. In this study, the impacts of interannual-to-decadal sea surface temperature (SST) variability on MHWs in 10 areas around Japan were evaluated using daily satellite-based SST data from 1983 to 2022. To evaluate these impacts, MHWs were detected using SST without the interannual-to-decadal variability, while keeping the threshold for the MHW detection unchanged. As a result, the annual MHW days averaged for the 10 areas were reduced by 53
A comparison between seismic observations and laboratory sound velocity data of candidate lower-mantle minerals provides key constraints on the chemical composition of Earth's deep mantle, where direct sampling is impossible. However, the composition of the lower mantle remains debated due to the scarcity of velocity data for minerals with realistic compositions. Here, we report picosecond acoustic measurements on (Mg0.81Fe0.19)O ferropericlase (fp19), MgSiO3 bridgmanite, and Mg0.88Fe0.13Al0.11Si0.91O3 bridgmanite (F13A11-bdg) up to 86 GPa at room temperature. The use of thin metal-film coatings on both sides of the samples improves optical coupling, enabling reliable measurements for opaque and insulating lower-mantle minerals. The VP of fp19 shows a clear reduction associated with the iron spin crossover near 55 GPa, whereas F13A11-bdg exhibits a monotonic increase with pressure. These results demonstrate the extended applicability of picosecond acoustics to realistic lower-mantle compositions under high pressure.
We propose an airborne ultrasound non-destructive testing method to visualize multiple defects in thin metal plates. Conventional amplitude-based imaging struggles to detect multiple defects due to signal attenuation caused by scattering at preceding defects. To address this, we investigated phase imaging and compared it with a method applying amplitude attenuation compensation to conventional imaging. Verification was conducted through finite element method analysis and experiments using a duralumin plate with three series-aligned wall-thinning defects. While conventional amplitude imaging identified only the defect closest to the excitation point, both investigated approaches successfully visualized all three defects, confirming the effectiveness of phase imaging. Furthermore, assuming practical field applications, phase imaging was evaluated at various incident angles (0 degrees, 45 degrees, and 90 degrees) relative to the defect alignment. Results demonstrated successful imaging across all angles, proving its robustness.
