Tootfinder

Blue supergiants in the Pinwheel Galaxy M101: comparison with H II region chemical abundances, spectroscopic distance and an independent determination of the Hubble constant
Fabio Bresolin, Rolf-Peter Kudritzki, Miguel A. Urbaneja, Eva Sextl, Adam G. Riess
https://arxiv.org/abs/2508.11837

Blue supergiants in the Pinwheel Galaxy M101: comparison with H II region chemical abundances, spectroscopic distance and an independent determination of the Hubble constant
We present a quantitative spectroscopic study of 13 blue supergiant stars in the Pinwheel Galaxy M101, based on data obtained with the Low Resolution Imaging Spectrometer available at the Keck I telescope. The average stellar metallicity decreases from ~1.9 Zsun near the center of the galaxy to ~0.3 Zsun at the optical outskirts. The galactocentric radial metallicity gradient is statistically consistent with previous studies of the gas-phase oxygen abundance from H II regions using the direct m…

Dynamical localization and delocalization for random Schrodinger operators with $\delta$-interactions in $\mathbb{R}^3$
Peter D. Hislop, Werner Kirsch, M. Krishna
https://arxiv.org/abs/2509.00824

Dynamical localization and delocalization for random Schrodinger operators with $δ$-interactions in $\mathbb{R}^3$
We prove that the random Schrodinger operators on $\mathbb{R}^3$ with independent, identically distributed random variables and single-site potentials given by $δ$-functions on $\mathbb{Z}^3$, exhibit both dynamical localization and dynamical delocalization with probability one. That is, there are regions in the deterministic spectrum that exhibit dynamical localization, the nonspreading of wave packets, and regions in the deterministic spectrum where the models also exhibit nontrivial quantum…