In search of a new era of UK X-ray astronomy.

X-ray astronomy is our gateway to the hot universe. More than half of the baryons in the cosmos are too hot to be visible at shorter wavelengths. Studying the extreme environments of black hole and neutron star vicinities also requires X-ray data. With the successful launch of India's AstroSat in 2015, and the few – but transformative – results from Japan's short-lived Hitomi mission in 2016, a new window has been opened into high-sensitivity fast timing and high X-ray spectral resolution. Together with the all-sky survey missions expected soon, X-ray astronomy is now exploring new parameter space. The UK has been at the forefront of this field since the 1970s and has traditionally punched above its weight in science return relative to the size of its X-ray community. But flat-cash science budgets and the rising costs of cutting-edge space missions bring diminishing roles for the UK in terms of both payload development and future science exploitation. To review the novel science possibilities enabled by recent and upcoming missions, and to discuss how to pave the way for X-ray astronomy in the UK, an RAS Specialist Discussion Meeting on “Timing and spectroscopy in the new era of X-ray astronomy” was held at Burlington House on 10 February 2017.