Kernel-phase imaging VLT/NACO paper!

In this new publication using the tools developed in the context of the KERNEL project, ANU-based PhD student Jens Kammerer announces the detection of eight low-mass companions to stars observed using VLT/NACO in the L-band, five of which were previously unknown,

Among these new companions, two appear at angular separations ranging between 0.8 and 1.2 λ/D (i.e. 80 and 110mas⁠), demonstrating that from the ground, kernel-phase makes it possible to achieve a resolution better than the traditionally accepted diffraction limit of a telescope.

Corner-plot of the best-fitting parameters for the two close companion candidates HIP50156 (top) and HIP39718 (bottom) recovered by the kernel-analysis of archival VLT/NACO L-band images.

Congratulations to Jens whose paper was accepted for publication by the Monthly Notices of the Royal Astronomical Society (MNRAS) and should appear in the June 2019 edition of the journal! The preprint version of the paper is already available for download on the website:

My Innovation Is… on Youtube?

Back in November last year, the concept of kernel-nuller was featured as one of the ten projects selected by the SATT Sud-Est in the context of the innovation challenge called “My Innovation Is…”. Yesterday, the following video was posted on youtube… enjoy!

The following text was extracted from the description of the video (available here):

SATT Sud-Est and its partners present the Superheroes of Innovation, winners of the My innovation is… 2018 competition. During the third edition of the “My Innovation Is…” competition, held on November 27, 2018 at the Palais des Papes in Avignon, France, 10 researchers and future startuppers from the public laboratories of the South & Corsica Regions presented their innovative projects before a jury of experts.

Ignacio CASUSO, Inserm, is able to visualize the nervous system at the molecular level. Sébastien GIRAUD (Aix-Marseille Université) is able to evaluate proprioception to better communicate with our body. Olivier CHUZEL of Aix-Marseille Université has the power to selectively kill cancer cells. Soraya MEZOUAR (Aix-Marseille University) is developing a new therapy using placental stem cells. Eric LECHEVALLIER (AP-HM) can describe and quantify the intensity of a bleed using a connected tool. Manuel ESPINOSA of the University of Corsica controls the storage of solar energy. Christine CONTINO-PEPIN from Avignon Université is able to extract and stabilize compounds of plant origin in an eco-compatible way. Michel Alain BARTOLI (AP-HM) is developing a stent graft dedicated to the endovascular treatment of aortic diseases. Mikaël CHELLI of the Centre Hospitalier Universitaire de Nice masters medical statistics thanks to an autonomous application. Frantz MARTINACHE (Observatoire de la Côte d’Azur) reveals the presence of extrasolar planets in search of habitable worlds. Faced with a merciless jury, they had to fight to convince and ensure the next generation of innovation.

It’s not every day you are called a “super-hero” of innovation 😉

Kernel-phase science paper accepted by A&A!

Romain Laugier, PhD student contributing to the KERNEL project, saw his first paper accepted by the journal Astronomy & Astrophysics. The paper shows how images affected by some amount of saturation can be salvaged to make them kernel-compatible again.

Using an archival HST/NICMOS dataset from 1997, Romain was able to show on a known low-mass binary that the recovery algorithm is effective. The signature of the 4.36 magnitude contrast companion, invisible in the original image, is present in the kernel-phase extracted from that image. This kernel-signature was used to constrain the position and contrast of the companion.

Saturated HST/NICMOS image of Gl 494.

This new resolved observation of the low mass companion to Gl 494 along with other recently published images, combined with a long series of archival radial velocity observations by two instruments, lead to very strong constraints on the orbital elements, and ultimately, the dynamical masses of this binary object.

Visual orbit of Gl 494 b.
Radial velocity of Gl 494 induced by the presence of the low mass companion.

Congratulations to Romain for successfully bringing this paper to the finish line: may this be the first of many others to come! The preprint version of the paper is available for download on the website:

My Innovation Is…

A few months ago, I heard about an innovation contest organized by SATT Sud-Est, a company that attempts to facilitate the transfer of technology from laboratories to the industry. The application process looked simple enough so I gave it a shot. It turns out that my application: basically a pitch for robust high-contrast instrumentation (aka a kernel-nuller), was among the ten selected for a live oratory contest that was held just a few days ago, in the city of Avignon inside the famous “Palais des Papes“.

Without direct industrial prospect for the kernel-nuller, it is no surprise that my pitch was not selected as the final winner. The awards went to Dr. Christine Contino-Pepin and Pr. Michel Alain Bartoli who will I have no doubt, be able to turn their ideas into profitable businesses!

Nevertheless, this was a lovely evening, and according to the feedback I received during the networking event that followed, attendees were quite intrigued and enthusiastic about the project. This is the real magic of astronomy in general and of extrasolar planets in particular that still manage to trigger people’s imagination. Even if science in general isn’t the most popular topic of conversation out there, public conferences about astronomy still manage to draw reasonably large and passionate crowds! If only we could trigger the same kind of amazement for all of the other sciences, the world would certainly be a better place!

Habilitation à Diriger des Recherches… soutenue!

Page de garde de la présentation HDR de Frantz

Le jeudi 4 octobre 2018 à l’Observatoire de la Côte d’Azur, j’ai enfin pu soutenir ma thèse d’habilitation à diriger des recherches (HDR), intitulée: “Repousser les limites de la diffraction pour l’astronomie à haute résolution angulaire”.

Parlez vous SCExAO? Présentation des différents avatars des outils graphiques de contôle de SCExAO

Après une (un peu trop longue?) présentation de mon travail de recherche depuis la soutenance de ma thèse de doctorat, en juillet 2005 et une série de questions, le jury composé de:

  • Jean Surdej, Université de Liège (Président du jury)
  • David Mouillet, IPAG (Rapporteur)
  • David Mary, Université de Nice Sophia-Antipolis (Rapporteur)
  • Olivier Guyon, Université d’Arizona (Rapporteur)
  • Jean François Sauvage, ONERA Chatillon (Examinateur)
  • Anthony Boccaletti, Observatoire de Paris (Examinateur)
  • Farrokh Vakili, Observatoire de la Côte d’Azur (Examinateur)

m’a fait l’honneur de me décerner l’habilitation à diriger des recherches en sciences… voilà une bonne chose de faite!

Devant le transparent de conclusion de la soutenance, de gauche à droite: Jean-François Sauvage, Anthony Boccaletti, Jean Surdej, Farrokh Vakili, David Mary, Frantz Martinache, Olivier Guyon et David Mouillet


Le fichier de ma présentation (beamer PDF) compilé depuis org-mode de Emacs peut être téléchargé depuis ma page web (30 Mb)!

Postdoctoral position in Astronomical Instrumentation for the KERNEL project

Schematic representation of an early design of the KERNEL test-bench


The KERNEL project, hosted by Observatoire de la Cote d’Azur (OCA) invites applications for a postdoctoral research position in the field of high-angular resolution astronomy starting no later than February 1, 2019. This position is funded by the European Research Council (ERC – CoG – grand agreement #683029) under the European Union’s Horizon 2020 research and innovation program.

The KERNEL project

KERNEL aims at enabling every optical and infrared astronomical facility to reach its ultimate angular resolution potential, often pushing beyond the formal diffraction limit, while preserving the full sensitivity. By looking at astronomical data as the result of an interferometric process, the KERNEL framework brings much needed robustness to high-performance observing techniques, required for instance for the direct detection of extrasolar planets.

The mission

The KERNEL framework offers a wide range applications that go from the post-processing of available archival data to high-performance focal plane metrology, partly coupled with high-contrast imaging. In order to develop and prototype the next generation of high-performance instruments and metrology monitoring tools for ground based telescopes and interferometers, the completion of the KERNEL project includes the construction of a general purpose test-bench, with elements that have already been successfully deployed for on-sky applications. The postdoc responsibility will be to oversee the completion of this KERNEL test-bench.

The test-bench primarily relies on a high-order segmented deformable mirror used to modulate the phase across a diffractive aperture and a high-cadence low-readout near-infrared camera, simultaneously in up to four complementary spectral bandpasses.

The multi-band aspect of the bench expands on the capability already offered by the KERNEL framework:

  • it extends the range of tolerated input instrumental phase, with applications such fringe tracking for long baseline interferometry and adaptive optics for large telescopes.
  • it provides further calibration capability, allowing for the acquisition of spectral differential kernel-phases

In addition, with its simple but agile high-contrast mode, the bench will also make it possible to experimentally validate observing strategies devised in the context of the project that bring robustness to aberrations to high-contrast direct detection.

How to apply

A Ph.D. in astronomy, physics, or a closely related field is mandatory. We are interested in individuals with several years of post-PhD research experience in the development and the scientific exploitation of instrumentation in the field of high angular resolution astronomy that include active wavefront compensation either in the laboratory or at the telescope. The candidate should be willing to collaborate with and assist graduate students that will use the KERNEL bench for their research projects. The candidate will also be encouraged to take advantage of the experimental setup and the KERNEL project members expertise to pursue his/her own research interests.

The candidate must also possess a strong background in the modeling, reduction and interpretation of diffraction dominated data (interferograms and/or AO-corrected images). Experience with the Python and/or the C programming language is highly desirable.

The initial appointment will be for two years, with possible extensions up to four years. The successful candidate will be hosted by the Lagrange Laboratory, with a lab located on the campus of Valrose, downtown the beautiful city of Nice, France.

To apply, please send a copy of your curriculum vitae, and a summary of your research interests. Also arrange for three reference letters to be sent to Frantz Martinache ( For full consideration, applications should be received before September 15, 2018, although applications will be reviewed up until the position is filled.

PhD in Astronomical Instrumentation for the KERNEL project: focal plane based extreme adaptive optics

The KERNEL project, hosted by Observatoire de la Cote d’Azur (OCA) invites applications for a PhD project in the field of high-angular resolution astronomy. This position is funded by the European Research Council (ERC – CoG – grand agreement #683029) under the European Union’s Horizon 2020 research and innovation program. The add was also posted on EURAXESS.

The adaptive optics revolution

Adaptive Optics (AO) has changed the face of observational astronomy, making ground based telescope able to live up to their angular resolution potential, and allowing us to dream up the upcoming generation of large 30m-class giant segmented mirror telescopes (GSMTs). Yet despite its incredible achievements, AO still hasn’t fully succeded in bringing the quality of astronomical images to its full potential, required for modern observing techniques such as high-contrast imaging and/or coupling into single mode fibers, enabling the use of photonic technology.

Objectives of the PhD project

The next major breakthrough will come from using information of great value, available in the focal plane, to directly to drive AO systems. Such an approach is finally possible today, thanks to the availability of high-cadence, low readout noise near-infrared detectors and that of enhanced real time computing capabilities. Observatoire de la Côte d’Azur (OCA) and the Subaru Telescope are teaming up to offer a PhD project that will turn this ambitious goal into a reality. This PhD is funded by the KERNEL project. It will be co-supervised by the KERNEL project PI F. Martinache (OCA) and the Subaru Coronagraphic Extreme AO (SCExAO) project lead O. Guyon (Subaru Telescope).

The successful applicant will benefit from state of the art hardware and expertise along with access to two complementary experimental setups, both taking advantage of the same software environment:

  • the KERNEL test-bench, located in Nice (France), with a unique multi-wavelength capability, and a segmented deformable provides the means to prototype applications for GSMTs and long baseline interferometry developments.
  • the SCExAO instrument itself, installed at the Nasmyth focus of the Subaru Telescope, located atop Mauna Kea (Hawaii USA), provides the means to validate strategies using unique on-sky validation capability and have a rapid impact on the community.

Application process

The PhD should preferably start in the Fall 2018. To apply, the candidate is required to send (email a copy of his vita, and a letter detailing his/her interest in the project along with a transcript of his/her master degree in physics, astronomy or a relevant engineering specialty. The candidate should be willing to work as part of a team, to collaborate with an international network of people involved with a wide variety of activities: data processing, astrophysical modeling, observing at the telescope, experimentation in optics and real-time computing.

Habilitation à Diriger des Recherches

Dans le but de soutenir mon Habilitation à Diriger des Recherches (HDR), j’ai soumis à mes rapporteurs la première version de cette thèse, intitulée: “Repousser les limites de la diffraction pour l’astronomie à haute résolution angulaire”.

Page de garde de la HDR de Frantz

Deux versions de cette thèse sont téléchargeables ici au format PDF:

Si mes rapporteurs m’y autorisent, la soutenance de cette thèse de HDR devrait avoir lieu le jeudi 4 octobre 2018, à l’Observatoire de la Côte d’Azur, sur le site du Mont Gros.

Entrée de la Grande Coupole de l’Observatoire de la Côte d’Azur, sur la colline du Mont Gros, à Nice.

Pour les curieux, une page de Wikipedia explique ce qu’est la HDR et quel est le rôle de cette tradition qui ne semble exister qu’en Europe ainsi que dans quelques pays d’Afrique du Nord.

La thèse est évidemment écrite en LaTeX. Pour la mise en page, j’ai choisi d’utiliser la classe tufte-latex, inspirée par les publications de Edward Tufte. La lecture de son livre intitulé The Visual Display of Quantitative Information et de son essai intitulé Essay: The Cognitive Style of Powerpoint: Pitching Out Corrupts Within durant mon premier contrat de post-doctorat à l’Université de Cornell ont eu une forte influence sur ma méthode de communication scientifique: je les recommande tous les deux!

MEDITES: Parcours Gaia

Pour la troisième année, j’interviens dans le programme MEDITES dans un parcours pédagogique qui présente la recherche en astrophysique à des élèves du secondaire. Cette année, le parcours est focalisé sur les méthodes observationnelles en astronomie: astrométrie, photométrie et spectroscopie, et parlent en particulier de la mission Gaia. Les supports des présentations que j’ai préparés pour l’astrométrie et la photométrie sont disponibles ici.

La parallaxe: trouver notre place dans l’univers

Slide extrait d’une présentation sur l’astrométrie et la mesure de la parallaxe faite dans le cadre du programme MEDITES.

Photométrie et exoplanètes

Slide extrait d’une présentation sur la photométrie et les propriétés physiques des planètes extrasolaires faite dans le cadre du programme MEDITES.

Pour ce parcours, j’ai mis au point et construit une expérience constituée d’un simulateur motorisé de couple étoile-planète et d’une mesure photométrique temps réel par une photodiode connectée à une carte Arduino. J’ai également développé un petit programme d’acquisition des données collectées par la carte Arduino qui permet de faire du traitement a posteriori des données photométriques. Un tutoriel décrivant la fabrication et l’utilisation de cette expérience sera publié cette année par le site du service éducatif de l’Observatoire de la Côte d’Azur.

Kernel-nulling talk in Grenoble

These are the slides of a presentation given on March 8, 2018 at IPAG, where I present research activities related to the KERNEL project, in particular the most recent development concerning the idea of kernel-nulling interferometry.

Predicted contrast detection limits for the L-band VIKiNG instrument concept proposed by Martinache & Ireland.

You can access the presentation file directly here.