Raphaël Galicher

email: raphael.galicher ' at ' nrc-cnrc.gc.ca phone: +1 250 363 6916

Post-doc at Herzberg Institute of Astrophysics, Victoria and Université de Montréal, Canada

Galicher et al. 2005, PASP
Galicher et al. 2007, CRAS
Galicher et al. 2008, A&A
Galicher 2009, PhD thesis (in French)
Galicher et al. 2010, A&A
Galicher et al. 2011a, A&A
Galicher et al. 2011b, ApJ
Since 2004, I have been involved in several projects dedicated to the direct imaging and the spectro-polarimetric characterization of exoplanets at wide separations (1 to 500AU), mainly Jupiter-, Neptune- and super-Earth-like planets around young nearby stars. In 2004, I worked at the Subaru telescope on a high contrast imaging apodizer (PASP paper) in the context of the Terrestrial Planet Finder (TPFC, NASA). The instrument I studied is now used or foreseen in most of the North American instruments for exoplanet imaging. Then, I spent four years (2006-2010) at the Paris Observatory (France) doing research and development in high contrast imaging using both laboratory experiments and numerical studies for both space missions (SPICES, ESA Cosmic Vision) and ELT (CRAS, A&A, and A&A on the Self-coherent camera that calibrates and reduces the speckle noise and A&A on an ELT achromatic coronagraph that attenuates the stellar light to look for faint objects in its neighborhood). Since 2010, I am working as a postdoc at the Herzberg Institute of Astrophysics in Victoria (British Colombia, Canada). I reduced all the images taken at Keck, Gemini North, Gemini South, VLT, HST for the International Deep Planet Survey by direct imaging from 2001 to 2011. I am now working on statistics to determine the giant planet frequency around nearby MFGKA stars. Moreover, I found several objects that could be Jupiter-like planets but I need to observe them one more time to confirm they are not background objects (some are very promising). I also developed a new background subtraction technique to obtain the first image of exoplanets at M-band (ApJ). I design and develop the official pipeline for the Gemini Planet finder Instrument (GPI). Since I left France, I have been in regular contact with my previous team at the Paris Observatory and I participate as much as I can to the instrumental developments that happen there.

HR 8799 system

I obtained the first image of exoplanets at M-band using an innovative background subtraction technique. These M-band detections extend the broad band photometric coverage out to 5microns and provide access to the strong CO fundamental absorption band at 4.5microns. The new M-band photometry shows that the HR 8799 planets are located near the L/T-type dwarf transition, similar to what was found by other studies. I also confi rmed that the best atmospheric fits are consistent with low surface gravity, dusty and non-equilibrium CO/CH4 chemistry models. ApJL paper. (Click on figures to enlarge)

First image of exoplanets at M-Band (2009 Keck HR 8799 data). Color diagram with planets at the L-T transition. Spectrum for planets HR 8799b, c, and d.

International Deep Planet Survey

In the context of the International Deep Planet Survey (IDPS) I developed a pipeline to process Adaptive Optics data and obtain high contrast images of hundreds of nearby star neighborhood. I reduced thousands of images taken from 2001 to 2011 with several instruments: Nirc2 at KeckII, NIRI at Gemini North, NICI at Gemini South, NACO at VLT, NICMOS on HST. I built a database of exoplanet candidates (>50), binary stars (>100), background objects (>300), and hosting star properties (distance, minimum and maximum age, proper motion, magnitudes, IR excess, and so on). I use my database for two objectives:
1/ find new exoplanetary systems
Our team had telescope time at Gemini North and Keck in 2011 to follow-up the exoplanet candidates (and find whether they are exoplanets or background objects). We will end the candidate follow-up in 2012. Some systems are very promising. I also obtained high angular resolution and high contrast images of disks at near-infrared wavelengths (future publications).
2/ determine the giant planet frequency in the 0-200AU range around nearby MFGKA stars.
I developed a numerical code to do Monte Carlo statistics on both the with-detected-exoplanet images and the with-no-detection observations. I consider thousands of synthetic exoplanets with random masses, orbital parameters, and ages. I derive the magnitude of every synthetic planet from Jupiter-like planet models (Baraffe's COND03 and DUSTY00 tables). I then find for each observed star how many of these planets could have been detected in the IDPS survey. I can then work out the giant planet frequency in the 0-200AU around nearby MFGKA stars.
Example of reduced images. The HR 8799b planet is visible in the image at the bottom left (you can guess the planet c in the same image if you know where it is).

Gemini Planet Finder Instrument

I am currently involved in the Gemini Planet finder Instrument (GPI) team. The GPI was built as a survey instrument to detect planets and image debris disks. GPI, its European counterpart SPHERE, and its Japanese equivalent HiCIAO/SCExAO will produce the first-ever robust census of giant planet populations in the 5-50 AU range, allowing us to 1) illuminate the formation pathways of Jovian planets; 2) reconstruct the early dynamical evolution of systems, including migration mechanisms and the interaction with disks and belts of debris; and 3) bridge the gap between Jupiter and the brown dwarfs with the first examples of cool low-gravity planetary atmospheres.
My contribution to the project is the development of the official automatic pipeline that the team has to provide to the community. The pipeline will apply high contrast imaging post-processing techniques to automatically find the planet candidates from the raw data, measure their photometry, spectrum and position, and compare to already known exoplanets, to-be-confirmed candidates, and background sources. A GUI interface (or equivalent) will give all the information to the user.

Instrumental developments

I spent about a decade doing research and development for high contrast imaging techniques. I did numerical simulations to optimize the instrumental designs and to determine the expected performance. I developed several optical benchs in laboratory to test the first prototypes of these techniques.
The first instrument I work on at the Observatoire de la Côte d'Azur is the Interfero Achromatic Coronagraph, an achromatic coronagraph based on a Michelson interferometer configuration.
In the context of the Terrestrial Planet Finder project (NASA), I developed an optical bench at the Subaru Telescope to demonstrate the Phase-induced amplitude apodization (PIAA) technique. Since my study (PASP), the technique has been introduced or foreseen in several instruments in North America.
PIAA principle

I then developed the High Contrast Imaging Bench (ITHD) during my PhD at the Paris Observatory. It is an optical bench built to compare high contrast imaging techniques (coronagraphs, speckle calibration techniques, deformable mirrors, wavefront sensors, IFS, etc) in the context of space mission (ESA Cosmic Vision) and E-ELT instrument proposals. I tested and developed on this bench the Self-coherent camera, an innovative wavefront sensor and speckle calibrator (CRAS, A&A, A&A). The instrument will be tested on sky at the Subaru telescope on the SCExAO bench by the end of 2012. I also worked on other benchs to test coronagraph concepts as the achromatic Multi-four quadrant phase mask coronagraph (A&A) for the E-ELT.
Numerical simulation results: detection of Earth-like planets (white circles), Neptunes (blue circles) and Jupiter (red circle) with a small space coronagraph using the Self-coherent camera.


Multi-four quadrant phase mask coronagraph principle. Laboratory performance with a full pupil (space telescope) and with an E-ELT pupil.

Numerical code for simulation of high contrast imaging instruments

Download the Meudon High Contrast Imaging code (Mehici). I developed the Mehici code to define the science cases of the SPICES mission proposed to the ESA Cosmic Vision in 2011. However, I built the code in a more general context to compare the different high contrast imaging instruments that are proposed in the field of direct imaging of exoplanets. I used a module-structure so that anyone can add its own instrument module (coronagraph, speckle calibration technique, etc). One can then associate its own instrument with other techniques and compare the performance of all instrumental configurations under the same assumptions (noises, planet spectra, star spectra, wavefront quality and so on). A PhD student (Paris Observatory) and I are currently working on and with the code to determine which kinds of planets (Jupiter, Neptune, super-Earth) can be detected in function of the telescope configuration and the hosting star properties (distance to the Earth, planet-star separation, spectral type). Members of the Paris Observatory team also work on upgrading the code for deformable mirror and wavefront sensor simualtions.

Teaching experiences

I had been moniteur and then ATER at the Université Denis Diderot (Paris) and at the Paris Observatory respectively.

From 2006 to 2009, I taught labs and tutorial for 3rd year university-level courses of mecanics and optics. Here are the documents I wrote for these courses (in French):
  • Partiel 2007 de L3: Waves and oscillations. The day Zygomar the clown invites the French national rugby team and a 4 years-old children group to his attraction park.
  • TD 1 et 2 et TP: Ray optics and physical optics for L3 professionnelle.

    From 2009 to 2010, I gave labs to master students in Astronomy and astrophysics (how to use a telescope, spectrometer, and CCD, image post-processing and interpretation). I gave courses on general physics to 1st and 2nd year university-level. I have been interviewed to present the astronomer job to teenagers. I also participated in public events to present astronomy and science. All documents are in French.
  • Course: The scientific approach given at the Diplôme d'Université: planet formation (video in French)
  • Course: How-to manual for manuscript and talk given at the Diplôme d'Université.
  • Course 1 and 2 and TP: LaTeX for beginners for the C2I formations.
  • Video Onisep: Astronomer, what is that?