Relativistic redshift of the star S0-2 orbiting the Galactic Center supermassive black hole.

The general theory of relativity predicts that a star passing close to a supermassive black hole should exhibit a relativistic redshift. In this study, we used observations of the Galactic Center star S0-2 to test this prediction. We combined existing spectroscopic and astrometric measurements from 1995-2017, which cover S0-2's 16-year orbit, with measurements from March to September 2018, which cover three events during S0-2's closest approach to the black hole.

Author Correction: A population of luminous accreting black holes with hidden mergers.

In this Letter, the spelling of author Benny Trakhtenbrot was corrected; the affiliation for author Sylvain Veilleux was amended; and a new ref. 9 was added to the Abstract with subsequent references renumbered; these errors have been corrected online.

A population of luminous accreting black holes with hidden mergers.

Major galaxy mergers are thought to play an important part in fuelling the growth of supermassive black holes. However, observational support for this hypothesis is mixed, with some studies showing a correlation between merging galaxies and luminous quasars and others showing no such association. Recent observations have shown that a black hole is likely to become heavily obscured behind merger-driven gas and dust, even in the early stages of the merger, when the galaxies are well separated (5 to 40 kiloparsecs).