Only about 19 Galactic and 25 extragalactic bonafide luminous blue variables (LBVs) are known to date. This incomplete census prevents our understanding of this crucial phase of massive star evolution which leads to the formation of heavy binary black holes via the classical channel. With large samples of LBVs one could better determine the

Short-timescale microlensing events are likely to be produced by substellar brown dwarfs (BDs), but it is difficult to securely identify BD lenses based on only event timescales t E because short-timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD

The scatter in the galaxy size versus stellar mass (M ⋆) relation gets largely reduced when, rather than the half-mass radius R e, the size at a fixed surface density is used. Here, we address why this happens. We show how a reduction is to be expected because any two galaxies with the same M ⋆ have at least one radius with identical surface

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2’s Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and

The scientific motivation of this thesis is to surpass some limitations in the state-of-the-art radiometers and spectropolarimeters used in Cosmic Microwave Background observations. The document follows the Three Papers Format of PhD theses. The first article, entitled A High Sensitivity Fourier Transform Spectrometer for Cosmic Microwave

The scientific motivation of this thesis is to surpass some limitations in the state-of-the-art radiometers and spectropolarimeters used in Cosmic Microwave Background observations. The document follows the Three Papers Format of PhD theses. The first article, entitled A High Sensitivity Fourier Transform Spectrometer for Cosmic Microwave