Another step towards a new era of Infrared Astronomy
GRAVITY+ achieves Breakthrough First Light with Adaptive Optics
The GRAVITY+ project, led by the Max Planck Institute for Extraterrestrial Physics (MPE) reached a key milestone this summer, with the first light of the state-of-the-art Adaptive Optics systems equipping the Very Large Telescope Interferometer (VLTI). These observations improve the sensitivity and contrast previously achievable with interferometry by more than an order of magnitude, opening up new prospects for the study at the highest angular resolution in the infrared, in particular for high-redshift quasars or exoplanet atmosphere. Looking ahead, laser guide stars, planned for summer 2025, will further enhance GRAVITY+’s capabilities, pushing astronomical research to new limits.
The GRAVITY+ project, a pioneering effort led by the Max Planck Institute for Extraterrestrial Physics (MPE), has achieved a major milestone with the first successful light captured through its newly commissioned Adaptive Optics (AO) systems at the Very Large Telescope Interferometer (VLTI). The new GRAVITY+ AO systems enable VLTI to reach a sensitivity and contrast over ten times greater than previous capabilities, allowing astronomers to study cosmic phenomena in unparalleled detail.
Interferometry is a powerful astronomical technique that combines light from widely spaced telescopes, effectively creating an immense 130-meter-wide virtual telescope. By coupling this technique with Adaptive Optics — a high-resolution technology that adjusts for atmospheric turbulence in real-time — GRAVITY+ achieves both ultra-high sensitivity and sharpness in infrared observations.
The GRAVITY+ initiative, which began in 2020, integrates four advanced AO systems on VLTI’s 8-meter-class telescopes, delivering correction precision on par with ERIS, another groundbreaking project spearheaded by MPE’s Infrared Group. Following the installation of GRAVITY-wide mode in 2021, which recently measured the mass of a black hole in the early universe, GRAVITY+ opens a new chapter in high-angular resolution astronomy.
Groundbreaking Observations Unveil New Cosmic Details
Already, GRAVITY+ has surpassed expectations with its inaugural observations, achieving major scientific breakthroughs:
Distant Quasars Revealed: GRAVITY+ observed a quasar at redshift z=4, the farthest quasar ever seen in the Universe. This extraordinary feat is pushing the limits of infrared astronomy and expanding our view of the universe’s earliest structures.
Atmospheric Analysis of Exoplanet HR8799: Using GRAVITY+’s unmatched sensitivity, astronomers have conducted a highly detailed spectrum of the atmosphere of HR8799, an exoplanet orbiting a star nearly 130 light-years away. This precision is enabling researchers to probe the chemical composition and potential atmospheric variations of distant worlds.
Massive Stars in Neighboring Galaxies: GRAVITY+ has opened new possibilities for studying massive stars within galaxies neighboring the Milky Way. Observing these colossal stars and potential binary companions sheds light on their formation and evolution, providing new insights into stellar dynamics in diverse galactic environments.
Next Steps in the GRAVITY+ Vision: Laser Guide Stars
With these initial achievements, GRAVITY+ is set to take another significant step forward. In summer 2025, laser guide stars will be implemented on each of VLTI’s 8-meter telescopes, a crucial addition that will further enhance the system’s resolution and open new pathways for observing some of the universe’s most elusive phenomena.
Statement Frank?
The GRAVITY+ project
The GRAVITY+ project will upgrade GRAVITY and the VLTI in order to open up the extragalactic sky for milliarcsecond-resolution interferometric imaging, and give access to targets as faint as K = 22 mag. GRAVITY+ will measure the black hole masses of active galactic nuclei across cosmic time, and obtain high-quality exoplanet spectra and orbits.
GRAVITY+ will provide wide-field off-axis fringe tracking, and improved sensitivity and contrast from new natural guide star and laser guide star adaptive optics for all VLT 8 m unit telescopes. The GRAVITY+ upgrades can start immediately, and can be implemented incrementally, keeping the impact on operation to a minimum. They will add new, globally unique science capabilities with every step. As an infrastructure upgrade of the VLTI, GRAVITY+ will serve all present and future VLTI instruments along with their communities.
Following a summer 2020 recommendation by ESO’s STC, GRAVITY+ went through a Phase A process, which was successfully concluded in summer 2021, in order to become ESO’s next VLT facility instrument. GRAVITY+ is built by a consortium including MPE, INSU/CNRS, University of Cologne, MPIA, CENTRA, University of Southampton, and associated partner KU Leuven, in close collaboration with ESO.
