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Microcalorimeters have shown remarkable success in delivering high-spectral-resolution observations of the hot and energetic Universe, and have paved the way to revolutionary new science possibilities in X-ray astronomy. There are several research areas in compact-object science that can only be addressed with energy resolution ΔE ≲ 5 eV at photon energies of a few kiloelectronvolts, corresponding to a velocity resolution of less than a few hundred kilometres per second, to be ushered in by microcalorimeters. Here we review some of the outstanding questions, focusing on how the research landscape is set to be transformed at the interface between accreting supermassive black holes and their host galaxies, in unravelling the structures of accretion environments, in resolving long-standing issues on the origins of energy and matter feedback, and in testing mass-scaled unification of accretion and feedback. The need to learn lessons from Hitomi and to make improvements in laboratory atomic data precision as well as plasma modelling are highlighted.

Proposer's Guide for the Atacama Large Millimeter/Submillimeter Array (ALMA) Cycle 9, Doc. 9.2, ver. 1.4

In the middle of the COVID-19 pandemic and while the ALMA antennas were still powered down, ALMA launched a global initiative to Redesign the User eXperience (RedUX). The RedUX Working Group (WG) interviewed ALMA users worldwide, equally spread amongst the three regions (North America, East Asia and Europe) between November 2020 and May 2021. The discussions that took place at the RedUX interviews were distilled and concrete suggestions for improvements were passed by the RedUX WG to individual teams responsible for ALMA software components, WGs or regions, as well as to the ALMA Integrated Science Operations Team., Published in The Messenger vol. 186, pp. 20-24, March 2022.

In the last decade, X-ray spectroscopy has enabled a wealth of discoveries of photoionised absorbers in X-ray binaries. Studies of such accretion disc atmospheres and winds are of fundamental importance to understand accretion processes and possible feedback mechanisms to the environment. In this work, we review the current observational state and theoretical understanding of accretion disc atmospheres and winds in low-mass X-ray binaries, focusing on the wind launching mechanisms and on the dependence on accretion state. We conclude with issues that deserve particular attention., Comment: 6 pages. Accepted for publication in Astronomical Notes (Proceedings of "The Extremes of Black Hole Accretion" workshop, held at ESAC, Madrid, in June 2015)