The project

The observatory

DAG (Eastern Anatolia Observatory): The PLACID exoplanet imager

The Doğu Anadolu Gözlemevi (Eastern Anatolia Observatory, abbreviated as DAG) is the new national observatory of Turkey. Here you can find more information about the DAG observatory.

Aim of the RACE-GO project

Exoplanet discoveries have fascinated the public for over two decades now, yet most detections are actually indirect. This is why direct imaging is presumably a compelling exoplanets detection technique, as it enables to study planet formation in-situ and allows for spectral characterization of planetary atmospheres. However, in spite of large survey time allocated to the latest high-contrast instrument, only a dozen planetary-mass companions have admittedly been directly imaged so far.

In practice, ground-based high-contrast imaging suffers from several hindrances that limit achievable contrast levels, in particular at close angular separation, where it matters the most. Being able to image a planet in orbit around its host star, in context within its own mature or nascent solar system, is simultaneously fascinating, scientifically invaluable, and still technologically very difficult to this day. The RACE-GO project intends to provide a breakthrough contribution ahead of the upcoming 40-m class “extremely large” telescopes, so one day we can hope to see a “pale blue dot” analog elsewhere in our galactic neighborhood, hence helping to answer questions such as “Are we alone?”.

Concretely, RACE-GO aims at bridging the latest digital liquid crystal display technologies with the exoplanet imager instruments currently equipping the largest ground-based astronomical telescopes. By combining the fastest active liquid crystal optical modulators with the best high-speed infrared cameras currently available, RACE-GO will explore the milli-second time domain to distinguish between residual optical errors from the Earth atmosphere, or inside the telescope beam train, and true astrophysical signals in the close vicinity of the targeted star (exoplanet, circumstellar disk etc.). In practice, RACE-GO will fund an upgrade to the upcoming PLACID* imaging instrument, built by a consortium of the University of Bern and the HEIG-VD in Yverdon, for the new DAG 4-m telescope in Turkey, using 60 guaranteed time observing (GTO) nights spread over two years to validate the approach on-sky, before bringing the technology onto 8-m observatories and possibly the 40-m European extremely large telescope (E-ELT).

(*) PLACID = Programmable Liquid-crystal Active Coronagraphic Imager for the DAG telescope

Research Activities 

PLACID Commissioning and Early Science

Our main research activity is currently focused on the commissioning and early science exploitation of the PLACID (Programmable Liquid-crystal Active Coronagraphic Imager for the DAG telescope) instrument. This includes not only instrumentation work, but also software development (data reduction pipeline, exposure time calculator etc.). The literature below outline the objectives, challenges, and preliminary results of the PLACID project along the way. One obvious key science objective of PLACID and RACE-GO is to look for circumbinary planets and disks, i.e. planets or circumstellar disks around binary (or triple) star systems, given that our instrument can mask as many host stars as needed.

SPIE Proceeding: The Programmable Liquid-crystal Active Coronagraphic Imager for the DAG telescope (PLACID) instrument: On-site status update ahead of first light

SPIE Proceeding: Discovery space and science with the PLACID stellar coronagraph

SPIE Poster: Discovery space and science with the PLACID stellar coronagraph

Understanding Discrete Pixelated Phase Coronagraphy with SLMs

This research effort explores the fundamentals of discrete pixelated phase coronagraphy, in particular by - but not limited to - using Spatial Light Modulators (SLMs) liquid-crystal display panels. The focus is on understanding the mechanics, applications, and advantages of this technology in high-contrast imaging systems, from numerical simulations to device characterization with interferometric metrology. We will also investigate alternative technologies to SLMs when implementing "adaptive coronagraphs", notably to improve optical throughput.

SPIE Proceeding: Future exoplanet direct imaging instruments: Simulating spatial light modulator-based pixelated focal-plane coronagraphy

SPIE Poster: Future exoplanet direct imaging instruments: Simulating spatial light modulator-based pixelated focal-plane coronagraphy

Coherent Differential Imaging (CDI)

Coherent Differential Imaging (CDI) relies on disentangling the temporally coherent signal from the host star (residual speckles, a frequent cause of "false positives" in our field) from bona-fide incoherent light from an off-axis astrophysical source of interest (planet, disk). This section explores the principles behind CDI, its implementation with a SLM, and its potential impact on direct imaging. This is one of the core goals of the ERC RACE-GO project. We will be able to validate the approach on-sky with PLACID at "slow speed" (30 Hz) before upgrading the instrument for high-speed millisecond CDI faster than the atmospheric turbulence.

SPIE Poster: Active coronagraphy and coherence differential imaging in unpolarized light with the Swiss Wideband Active Testbed for Coronagraphic High-Contrast Imaging (SWATCHi) 2.0