The unprecedented rest-frame UV and optical coverage provided by James Webb Space Telescope (JWST) enables simultaneous constraints on the electron density ( $n_{\rm e}$) and temperature ( $T_{\rm e}$) of ionized gas in galaxies at $z\,\gt\,5$. We present a self-consistent direct method based on multiple O III] ( $\lambda \lambda$1661, 1666) and [O

Dynamical mass measurements of compact stars in X-ray transients demand the detection of optical/near-infrared counterparts in quiescence. Out of the 73 black hole candidates in X-ray transients, optical and near-infrared quiescent counterparts have only been identified for 34 objects. We present ULTRACAM photometric observations of nine candidate

Context. The Galactic black hole candidate MAXI J1810−222 was recently reported to exhibit a notable absorption spectral feature at around 1 keV in low-resolution X-ray spectra from detectors resembling charge-coupled devices. The feature is typically correlated with the spectral state of the source being stronger in the soft states, as often

We present a ground-based transit detection of HIP 41378 f, a long-period (P = 542 days), extremely low-density (0.09 ± 0.02 g cm −3) giant exoplanet in a dynamically complex system. Using photometry from Tierras, TRAPPIST-North, and multiple Las Cumbres Observatory Global Telescope sites, we constrain the transit center time to T C,6 = 2460438.891

Large-amplitude prominence oscillations offer diagnostic information relevant to understanding the magnetic and plasma structure of solar prominences. Accurate prominence seismology requires the use of reliable models. The so-called pendulum model for large-amplitude longitudinal prominence oscillations has demonstrated robustness against

3I/ATLAS is the third interstellar object discovered to date, following 1I/'Oumuamua and 2I/Borisov. Its unusually high excess velocity and active cometary nature make it a key probe of the Galactic population of icy planetesimals. Understanding its origin requires its past trajectory through the Galaxy to be traced and the possible role of stellar