This work shows that aspherical surfaces obtained by the general equation of stigmatic sequential optical systems are very sensitive to wavelength. The application these surfaces to broadband lens-based systems is limited by the system aperture.

Context. The z ∼ 0.1 type-2 QSO J1430+1339, known as the " Teacup", is a complex galaxy showing a loop of ionised gas ∼10 kpc in diameter, co-spatial radio bubbles, a compact (∼1 kpc) jet, and outflow activity. Its closeness offers the opportunity to study in detail the intricate interplay between the central supermassive black hole (SMBH) and the

Tidal streams of disrupted clusters are powerful probes of the gravitational potential of the Galaxy and they are routinely detected in the stellar halo of the Milky Way. It was recently shown that tidal streams of open clusters can now also be detected within the Milky Way disc. In this work, we highlight the fact that disc tidal streams also

This is mostly a bug fix release. Some changes to bounding strategy. Some warnings were added. See more details in the changelog.

Aims: We investigate the previous microlensing data collected by the KMTNet survey in search of anomalous events for which no precise interpretations of the anomalies had been suggested. From this investigation, we find that the anomaly in the lensing light curve of the event KMT-2021-BLG-1547 is approximately described by a binary-lens (2L1S)