Progress in the understanding of physical phenomena and objects in the Universe is intimately linked to the development of new means and methods of observation, which are the central object of research in our instrumental astrophysics team. Our MPO team has the particularity to gather researchers in astrophysics interested in the development and the consolidation of methods and means of astrophysical observation (research in instrumentation) as well as their exploitation (research in observational astrophysics). Our scientific fields of activity, atmospheric optics (OAtm), adaptive optics (OA), optical interferometry (IO), very high-contrast imaging (HCI) & signal processing (TS), cover quite exhaustively the perimeter of the INSU High Angular Resolution Specific Action (ASHRA)
The objectives of our team for the next 5 years (2023-2027)
Objective #1: to preserve a team framework that favors human-sized projects
In the HRA perimeter, the activity of our team members covers the upstream R&D of concepts and prototypes, the tests and qualification on sky of innovative concepts, the participation in the realization of instrument projects intended for the community and their astrophysical exploitation. If the large projects, serious in terms of funding and stakes, are the strategic activity that serves to size the teams, the less visible upstream R&D phases are just as essential: not only are they the scene of innovation that can change the face of future astronomy, but the excitement and lightness that characterize them also provide the oxygen that allows us to find pleasure in our work. The first objective of our team is to preserve this framework of innovation and oxygenation.
MPO is first and foremost a working environment for (assitant-)professors, researchers, PhD students and post-doctoral fellows: a collegial discussion framework for individuals who, even if they work on different applications, share a language and tools that link them and allow synergies. The weekly team meeting, the "MPO Science coffee", is scheduled on Mondays around noon and is a popular time to share and test raw and vulnerable ideas in a caring environment.
We recognize that instrumental projects concerning large research infrastructures impacting the international community are important. For reasons and history prior to the creation of our team, our laboratory has not had a strong involvement in the 1st generation ELT projects, whereas a participation in the METIS instrument would have made sense, especially given the complementarity with the expertise acquired in the framework of MATISSE. However, one of the main astrophysical applications of the instrumental research carried out in MPO is the characterization of extrasolar planets and the team is now clearly positioned to contribute to the realization of 2nd and 3rd generation instruments of the ELT ANDES and PCS.
We remain globally vigilant about the risk of a headlong rush: going faster to position ourselves on the most important projects in the hope of continuing to recruit and accredit, requires taking risks on means and availabilities already strongly under pressure. The team protects individuals, recognizes the need to have an enriching individual experience that contributes to the community but is not consumed by the needs and ambitions of the collective.
The team is there to ensure that more exploratory upstream R&D and small projects on niche applications are sanctuarized: thus, observation from Antarctica with ASTEP and the development of adaptive lenses MAL, planetary adaptive optics on small apertures with AOC, on-board turbulence measurement means such as AIR-FLOW and PSAUM, benefit from the team framework. Some of these niche activities, have in practice an important impact for the community, especially in France where the HRA is preponderant: the prediction of turbulence of large observing sites or the characterization of the seeing of dome, the ability to measure discontinuities in the wavefronts are solutions that our team brings on large research infrastructures.
Objective #2: contribute to the evolution of astrophysical instrumentation
Instrumentation for astrophysics does not exist "off-the-shelf": each new instrument is a unique prototype and a site of innovation. In the wake of the use of electronic sensors and the computerization of instruments now acquired, new pathways continue to influence the design and operation of instruments. The team contributes to three evolutionary paths of astrophysical instrumentation that becomes adaptive, compact and continues to push the limits.
Adaptive instrumentation (adaptive optics & fringe tracking)
Adaptive optics (AO) and its interferometric counterpart (fringe tracking - FT) are already integral subsystems of observatory and instrument design. With both an expertise in AO itself (CAOS simulation means, AOC test platform on the Calern plateau), wavefront measurements optimizing the performance of high contrast imaging (ZELDA, APF-WFS, SCC), implemented on laboratory experiments (SPEED, KERNEL or HiCAT@STScI) or large active instruments (VLT/SPHERE and Subaru/SCExAO), the work in our team shows that the best performance is obtained by implementing a systemic approach, combining information from several analysers.
In addition to this systemic approach, which is especially relevant in the context of HCI, the team conducts R&D on new concepts in wide field AO, planetary with AOC (contributing to the observations of Jupiter by JOVIAL) and / or multi-object (VWFWFS concept). Fringe tracking is not left out either: the ERC KERNEL has allowed to prototype HEIMDALLR, the metrological module of the VLTI/ASGARD instrumental suite, for which the laboratory will ensure the integration from 2024 and the R&D on HFT (Hierarchical Fringe Tracker) continues with the prospective of an HFT-6T intended for the CHARA interferometer which will boost the observation capabilities of the SPICA-VIS instrument. Eventually, an HFT-4T could be installed at the VLTI with a very important potential impact on the AGN observation program motivating new transverse collaborations.
Compact instrumentation
Benefiting from the dynamics created by the KERNEL and ANAtOLIA projects, a point of convergence of the team concerns the miniaturization of instruments. This effort of miniaturization is manifested with the implementation of integrated optics for interferometry (HFT & Kernel-nuller) and spectroscopy (AWG technology) via two projects, IO4OI & C-SPEC, financed within the framework of PEPR Origins; as well as tools for characterization of turbulence with PSAUM (low-cost version of ANAtOLIA which is itself a compact version of CATS) and AIR-FLOW.
This miniaturization effort is partly motivated by the prospect of developing on-board solutions, on the ground or in space, allowing new industrial applications to be considered, while being more energy efficient.
Instrumentation at the limits
One of the driving forces behind innovation is the search for performance, and many of our projects seek to push back the limits of instrumentation and observations. This research "at the limits" is manifested in the exploitation of astrophysical data: SPHERE data in collaboration with the LAM, MUSE data with the CRAL, the kernel-phase imaging mode of JWST (NIRISS & NIRCAM) in collaboration with the University of Montreal, or kernel observations on Subaru/SCExAO in collaboration with UC Irvine. In all cases, these programs benefit from the implementation of detection algorithms defined on the basis of dedicated statistical tests.
Pushing the limits motivates R&D, notably the development of alternative interferometric recombiners: the HFT concept which seeks to push the limit magnitude of observable sources with interferometry to allow the observation of cosmological sources; the kernel-nuller which wants to allow high-contrast imaging at the resolution limit of interferometers (VLTI/ASGARD dynamics) ; the revisiting of intensity interferometry for bases and wavelengths beyond the capabilities of current interferometers, in collaboration with our neighbors from the Institut de Physique de Nice, which plunges us into quantum optics with R&D on the Calern plateau and on the VLTI, and in the line of sight, a project exploiting the CTA collectors.
Objective #3: strengthen our links with the industrial world
The solutions of fine metrology and the search for performance in detection applications generate interest among industrialists, who follow and contribute to our work. This relationship manifests itself in the development of new components, such as the support of the development of adaptive secondary mirrors by the company TNO, the co-design of integrated optics components with the company Bright Photonics. Our team also contributes to the creation of turnkey solutions such as the AIR-FLOW instruments (deployed at the CFHT or LBT), or the ANAtOLIA station, intended to be duplicated after delivery to the ESA. These solutions also include the development of simulation tools. Our relationships sometimes involve the provision of services and / or training of future employees: processing short-time exposure images from the ground of satellites for Ariane Group; implementation of detection algorithms including Machine Learning with the company ACRI-ST.
This synergy with industry is also obvious in the joint response to calls for tenders, particularly from ESA (Active Optics in deployable systems for future Earth Observation and Science missions, Kernel-Nuller Telescope, ANAtOLIA). In this ecosystem, we have a privileged relationship with the company TAS-F (joint laboratory TAS - OCA since 2018) which regularly accompanies us in these tenders.
Finally, our team plans to support the creation of a startup called ATTMMOS (Atmosphere & Turbulence Monitoring instrumentation and MOdeling Systems), intended to ensure the commercialization of replicas of the ANAtOLIA prototype and continue to do R&D. A great application is emerging for these stations integrating predictive potential, for the production of solar and wind energy from local measurements. Current contacts with the MASEN agency should eventually allow access to production sites in Morocco, but in the meantime, we are considering a pilot installation on the Calern site to predict the electrical production of a solar panel.
Objective #4: continue to better integrate signal processing
Signal processing (SP), which already supports many projects and is integrated with the other objectives of the team, is strategic and deserves the emphasis of a dedicated objective. The anticipation of post-processing techniques in the development of new instrumental concepts is a real trend, called co-design. The kernel-nuller or the HFT hierarchical fringe-tracker are examples of co-design, with an optical design that is altered to take into account detection/measurement constraints in order to enhance the state of the art.
SP supports many applications and three use cases can be cited: (i) fringe control under unsteady conditions that requires the implementation of adaptive control laws (studied in the HFT framework); (ii) exploitation of short-exposure imaging approaches: Despite a generalization of AO, approaches derived from speckle imaging and lucky imaging remain strategic approaches, adapted for example to the use case of optical telecommunications and for which it is critical to operate even when operating conditions are sub-optimal; (iii) the development of dedicated algorithms that allow to push the scientific exploitation of instruments to its maximum (e.g., VLT/MUSE imaging, JWST). Such work produces methods that can be used for other instrumental configurations (e.g. radial velocity detection or astrometry for GAIA), and creates inter-team (e.g. TOP and P2S) and even inter-laboratory collaborations. In addition, processing problems arising from instrumentation often raise fundamental methodological questions that generate research in signal and statistical learning.
Finally, we also see, as in many fields, the techniques of artificial intelligence and especially machine learning (ML) increasing in power. Our team is already exploring the possibilities opened by these approaches in a detection logic (in particular in collaboration with ACRI-ST) or to predict turbulence (ANAtOLIA). It is also in the metrological applications of our team (ZELDA, APF-WFS) that this ML approach should bring new advantages, such as making them usable in a non-linear regime, which would increase their capture domain.
Objective #5: to contribute usefully to the local training offer
The staff of MPO considers that instrumental astrophysics is a stimulating and rewarding training framework and would like to see this framework even more valued. Our permanent staff, who are mostly (assistant-)professors, are strongly involved in the MAUCA Master course and in the organization of the new Erasmus+ MASS Master course, both for the animation and for the proposals of training modules. If UCA is today associated with the MASS project, it is essentially thanks to the local expertise on instrumentation carried by our team, which is not present in the other partner universities (Belgrade, Bremen & Rome).
Our team also contributes to the animation of non-master courses, by being involved in the Certificate in Sciences of the Universe (CfSU) with a module on instrumentation, as well as in the university diploma in observational astrophysics (DUAO).
The R&D work in instrumentation differs from purely astrophysical subjects because it offers students (PhD students & interns hosted in the team) professional skills that can be valorized outside the academic world: laboratory methods, work in clean space, design, integration and alignment of advanced optical designs, implementation of actuators driven by computer programs, implementation of servo loops, etc.
The team hosts several projects financed through industrial contracts which are opportunities for newcomers to the world of work leading to a doctoral degree. We recognize, however, that for students destined for academic careers in astrophysics, the applied dimension of our projects can become a handicap. Maintaining a form of transversality through joint projects with the other thematic teams of the laboratory helps to temper this limitation. But the reality is that the recruitment of a young researcher is a strategic marathon with a very low probability of success.
Our team should make this reality explicit when hiring PhD students, who are sometimes recruited outside of the astrophysics Master's program. This is a recurrent topic of discussion for the team, which has been confronted with several thesis interruptions in recent years, strongly marked by the COVID period. We have decided to propose, starting next year, a series of articles on our web page for student candidates, which will aim to clarify and detail: the expectations of a PhD student starting a thesis in instrumentation, a presentation of the professional skills, a presentation of several possible post-thesis paths. We would also like to take advantage of this space to generate vocations among young women, who are still too much in the minority in our training. One idea currently being evaluated would be to propose interviews/profiles of female colleagues who have had successful careers in our field.
Structuring projects for the coming years
The validation of these five objectives of the team will benefit from the existence or the forthcoming establishment of several sources of funding.
ANAtOLIA (Atmospheric moNitoring to Assess the availability of Optical LInks through the Atmosphere)
This ESA contract, led by Aziz Ziad, and with a total budget of 2M€ brings 1.2M€ of resources to the team. ANAtOLIA has allowed the recruitment of four engineers: a project manager, an instrumentation engineer, an instrumental control engineer and a data processing and analysis engineer. The project, started in February 2021, will end in February 2025. It involves three permanent DFO researchers: É. Aristidi, M. Carbillet and A. Ziad.
A start-up, called ATMMOS, is being created with the help of CNRS-Innovation, the PACA-Est incubator, the innovation department of UCA-Idex. The first objective of this startup is to valorize the R&D carried out within the framework of the project by ensuring the commercialization of the ANAtOLIA station and the compact & low-cost patented instrument PSAUM, both intended to be replicated. ATTMOS will also be a place of R&D to answer other needs in prediction of atmospheric conditions including turbulence, necessary for an intelligent programming of astronomical observations, for the choice of the most available OGS ground stations to ensure telecommunication links with satellites, without forgetting the prediction of the energy production of solar and wind stations
ANR MELBA (Multi-Scale Broadband Study of Active Galactic Nuclei)
This ANR in partnership with LESIA and coordinated by Romain Petrov, brings 300 k€ of means in the team, with 24 months of post-doctorate, the financing of a thesis, equipment, and whose goal is to contribute to increase the sensitivity (in term of limit magnitude), and consequently in sky coverage, of GRAVITY+ and of new modes of use of MATISSE in synergy with GRAVITY: GRAV4MAT & MATISSE-Wide The project, started in 2021, will end in 2025.
With R. Petrov, Olivier Lai and Sylvie Robbe-Dubois, our team is also very involved in the realization of the adaptive optics of GRAVITY+, which mobilizes many forces of the laboratory, and will contribute to increase tenfold all the observing modes of the VLTI, which with an increased sensitivity, will finally allow to observe a large number of cosmological sources at high angular resolution
PCS Roadmap
ESO has made the strategic choice to postpone the realization of an XAO instrument at the focus of the ELT after the realization of the ANDES and MOSAIC instruments. The direct imaging and the characterization of extrasolar planets in the habitable zone of the stars of the solar neighborhood remains more than ever one of the most ambitious objectives of the various prospective programs in Europe and in the rest of the world.
The community in France and in Europe has structured itself around a roadmap for PCS, of which one of the next milestones will be the deployment of an upgrade of the SPHERE instrument. The PCS roadmap is currently not fully funded (OPTICON22 application failed) but will be the subject of new structuring calls in the context of Horizon Europe. The last project submitted has anchored the upstream R&D work conducted by Patrice Martinez with SPEED.
Supported by multiple sources of funding, SPHERE+ is becoming a reality. The laboratory has hosted the Kick-Off meeting of the project in October 2022, and the organization that is being set up includes Gaël Chauvin as Project Scientist and Mamadou N'Diaye as Co-I.
The VLTI/ASGARD instrumental suite
The VLT-2030 colloquium allowed to bring to the attention of ESO, the existence of the ASGARD instrumental suite project, for an installation on a VLTI visitor focus. The project has been formally proposed to ESO in 2022 and has recently been examined by the STC whose official return is still awaited. The informal feedback is very positive but the project will have to be phased with the integration of GRAVITY+ which is a priority for the VLTI strategy.
ASGARD brings together three independently funded instruments: BIFROST (PI Stefan Kraus, U. Exeter), NOTT (PI Denis Defrère, KU Leuven) & HEIMDALLR (PI Michael Ireland, ANU). The ERC KERNEL had allowed to prototype and validate the architecture of the HEIMDALLR metrological instrument. Frantz Martinache & Mamadou N'Diaye are Co-I of the project, whose consortium agreement has just been signed by all partners. The Lagrange laboratory will host the integration of HEIMDALLR from the second half of 2024 before shipping to Paranal. Before that, we will ensure the reception and the characterization of the deformable mirrors which will be used at the focus of the VLTI, from 2023. In addition to the involvement in the instrumental realization, we would like to generate interest in the thematic teams, in particular the stellar physics team and the transverse exoplanet team (where the project has already been presented).
PEPR Origins
Our team has been strongly involved in the development of several R&D actions that have been integrated into the PEPR Origins. F. Martinache is PI of a PEPR workpackage called IO4OI (Integrated Optics for Optical Interferometry), with a budget of 1.4 M€ for activities in partnership with IPAG and LESIA. Martinache is also Co-I of another workpackage entitled C-SPEC (Compact Spectroscopy), carried by IPAG and with a comparable budget. From the point of view of our team, the two activities in synergy will allow to capitalize on the advances of the ERC KERNEL and to advance the solutions of integrated optics for astrophysical instrumentation. This project, which will start in 2023, will last six years, financing as many years of post-doctoral contracts, several theses, and several hundred k€ of technical achievements, prototypes and demonstrators that will be deployed on the sky.
