A number of challenges to the standard Λ CDM model have been emerging during the past
few years as the accuracy of cosmological observations improves. In this review we discuss …

The advent of the second data release of the Gaia mission, in combination with data from
large spectroscopic surveys, is revolutionizing our understanding of the Galaxy. Thanks to …

Measurement of the distances to nearby galaxies has improved rapidly in recent decades.
The ever-present challenge is to reduce systematic effects, especially as greater distances …

We present a cross-calibration of Hipparcos and Gaia EDR3 intended to identify
astrometrically accelerating stars and to fit orbits to stars with faint, massive companions …

We describe the catalogs assembled and the algorithms used to populate the revised TESS
Input Catalog (TIC), based on the incorporation of the Gaia second data release. We also …

Context. Gaia Data Release 2 (Gaia DR2) contains results for 1693 million sources in the
magnitude range 3 to 21 based on observations collected by the European Space Agency …

Context. The second Gaia data release (Gaia DR2) provides precise five-parameter
astrometric data (positions, proper motions, and parallaxes) for an unprecedented number of …

Aims. The goal of this paper is to demonstrate the outstanding quality of the second data
release of the Gaia mission and its power for constraining many different aspects of the …

Context. The assembly history experienced by the Milky Way is currently being unveiled
thanks to the data provided by the Gaia mission. It is likely that the globular cluster system of …

A new realization of the International Celestial Reference Frame (ICRF) is presented based
on the work achieved by a working group of the International Astronomical Union (IAU) …