First Light for GRAVITY Wide at the VLTI

Published: 22 Jun 2022

GRAVITY+ is the ongoing upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) with wide-separation fringe tracking, new adaptive optics, and laser guide stars on all four 8-m Unit Telescopes (UTs), for ever-fainter, all-sky, high contrast, milliarcsecond interferometry. GRAVITY+ just reached its first milestone: GRAVITY Wide.

GRAVITY Wide combines the dual-beam capabilities of the VLTI and the GRAVITY instrument to increase the maximum separation between the science target and the reference star from 2 arcseconds with the 8.2m Unit Telescopes up to several tens of arcseconds, limited only by the Earth's turbulent atmosphere. This increases the sky coverage of GRAVITY by two orders of magnitude, opening up milliarcsecond resolution observations of faint objects, and in particular the extragalactic sky. The first observations in 2019 - 2022 include first infrared interferometry of two redshift z∼2 quasars, as showcased in the recently published GRAVITY Wide first light paper.

All commissioning data supporting the first light paper are now publicly available in the ESO Science Archive and can be queried from the GRAVITY Commissioning webpage. GRAVITY Wide is officially offered to our community starting with Period 110. A science verification, with publicly accessible data, is scheduled in mid-June 2022.