Hélène (Di Nella) Courtois (born 1970) is a French astrophysicist specialising in cosmography. She is a professor at the University of Lyon 1 and has been a chevalier of the Ordre des Palmes Académiques since 2015.
|Born||1970 (age 49–50)|
|Alma mater||University of Grenoble 1|
|Known for||Laniakea Supercluster|
|Institutions||University of Lyon 1|
|Thesis||Structure et cinématique de l'univers local (1995)|
|Doctoral advisor||Georges Paturel|
As the director of a research team at the Lyon Institut de Physique des 2 Infinis (IP2I)—formerly the Institute of Nuclear Physics (IPNL)—and co-director of two international teams (Cosmic Flows and CLUES), she is best known for her investigations into the dynamic cosmography of the Universe. Her work has concentrated on the distribution of matter in the large-scale structure of the Universe. In 2006, she participated in the confirmation of the acceleration in the expansion of the Universe via the study of supernovae. In 2014, she proposed a redefinition of the notion of galactic superclusters, and identified the Laniakea Supercluster, an agglomeration that is bigger than the Virgo Supercluster by a factor of 100. In 2017, she showed that cosmic voids produce a repulsive effect resulting in galactic displacements; this may also explain the cold spot in the cosmic microwave background.
Courtois began her research into the large-scale structure of our cosmic neighbourhood in the early 1990s while at the Lyon Observatory. In 1994, she revealed a superstructure comprising 27,000 galaxies, with a radius of about 290 million light-years. By studying the distribution of thousands of galaxies and modelling their structures, her team showed that these galaxies were not spherically distributed in space, but instead created a shape like a squashed football or a silkworm cocoon.
Courtois and her team have studied the convergent behaviour of the galaxies of the Laniakea supercluster. By modelling the movement of galaxies as though they were streams in a watershed or basin, they were able to map out the boundaries of this local agglomeration. They have adapted the technique to model the Vela Supercluster, which was discovered in 2016. They used their data to compute the flow rate of the galaxies towards the 'centre', thereby making it possible to infer the masses of the galaxies. Using this information, they will be able to determine the shape and size of the Vela supercluster.
In 2017, Courtois revealed two discoveries: one, called the Dipole repeller, and the other, on the cosmic microwave background cold spot, which could potentially explain the propagation of our galaxy through space at about 2 million kilometres per hour.
In 2019, her team released a new map of the local universe, encompassing a volume 10 times larger than that released in 2014.
In the 2000s, Courtois led the cosmology team at the Lyon Observatory. In 2006, she set up the research programme Cosmic Flows. Its major result has been the discovery of the frontiers of the supercluster named Laniakea that defines our cosmic neighbourhood.
Since 2013, she has been the head of the IP2I Observational Cosmology / Euclid research group. It is one of the world leaders in the field of cosmology dedicated to the observation, analysis and digital reproduction of the distribution and dynamics of dark matter and galaxies in the nearby universe.
Courtois oversaw the creation of a comprehensive programme of university studies in the sciences of the universe, hosting annually more than 500 students from University of Lyon 1. Courtois has been an expert adviser at the European Commission for research and education programmes in physics and astrophysics since 2009. She is also a patron of the Vaulx-en-Velin planetarium.
In 2015, Courtois was named a senior member of the Institut Universitaire de France and was made a chevalier of the Ordre des Palmes Académiques. She also received a festival prize for her film Cartographier l'univers : à la découverte de Laniakea.
In 2016, she became a vice-president of the University of Lyon 1, responsible for international relations.
Her book Voyage sur les flots de galaxies won the 2017 Prix Ciel & Espace du livre d'astronomie. In 2017, she was ranked in the top 50 most influential French personalities by Vanity Fair.
In 2018, she received the "Eureka" prize for science communication. She was also elected as the most influential French Scientist of the year by the Foreign affairs ministry.
In 2019, she was nominated in the top 3 of the 50 most influential women in her home city, Lyon.
- Di Nella, Hélène; Couch, W.; Paturel, G.; Parker, Q. (1 November 1996). "Are the Perseus—Pisces chain and the Pavo—Indus wall connected?". Monthly Notices of the Royal Astronomical Society. 283 (2): 367–380. arXiv:astro-ph/9611211. Bibcode:1996MNRAS.283..367D. doi:10.1093/mnras/283.2.367.
- Paturel, G; Andernach, H.; Di Nella, H. (July 1997). "Extragalactic database VII. Reduction of astrophysical parameters". Astronomy and Astrophysics Supplement Series. Astron. Astrophys. Suppl. Ser. 124 (1): 109–122. arXiv:astro-ph/9806140. Bibcode:1997A&AS..124..109P. doi:10.1051/aas:1997354.
- Paturel, Georges; Di Nella, Hélène; Terry, Jean-Noël; Theureau, Gilles (1998). "Interpretation of the galaxy structure surrounding the Local Supercluster". Comptes Rendus de l'Académie des Sciences, Série IIB. 326 (12): 933–938. arXiv:astro-ph/9807171. Bibcode:1998CRASB.326..933P. doi:10.1016/S1251-8069(99)80051-9.
- Tully, R. Brent; Shaya, Edward J.; Karachentsev, Igor D.; Courtois, Hélène M.; Kocevski, Dale D.; Rizzi, Luca; Peel, Alan (March 2008). "Our Peculiar Motion Away from the Local Void". The Astrophysical Journal. 676 (1): 184–205. arXiv:0705.4139. Bibcode:2008ApJ...676..184T. doi:10.1086/527428.
- Courtois, Hélène; Pomarède, Daniel; Tully, R. Brent; Hoffman, Yehuda; Courtois, Denis (14 August 2013). "Cosmography of the Local Universe". The Astronomical Journal. 146 (3): 69. arXiv:1306.0091. Bibcode:2013AJ....146...69C. doi:10.1088/0004-6256/146/3/69.
- Tully, R. Brent; Courtois, Hélène; Hoffman, Yehuda; Pomarède, Daniel (4 September 2014). "The Laniakea supercluster of galaxies". Nature. 513 (7516): 71–73. arXiv:1409.0880. Bibcode:2014Natur.513...71T. doi:10.1038/nature13674. PMID 25186900.
- Hoffman, Yehuda; Pomarède, Daniel; Tully, R. Brent; Courtois, Hélène (30 January 2017). "The dipole repeller". Nature Astronomy. 1 (2): 0036. arXiv:1702.02483. Bibcode:2017NatAs...1E..36H. doi:10.1038/s41550-016-0036.
- Courtois, Hélène (2016). Voyage sur les flots de galaxies - Laniakea, notre nouvelle adresse dans l'Univers. Dunod. ISBN 978-2100738908.
- Courtois, Hélène; Acker, Agnès (2016). Astrophysique - Rappels de cours, exercices et problèmes corrigés. Dunod. ISBN 978-2100742240.
- Tognini, Michel; Courtois, Hélène (2019). Explorateurs de l'espace. Dunod. ISBN 978-2100781607.
- Courtois, Helene (2019). Finding Our Place in the Universe. Cambridge, Massachusetts: MIT. ISBN 9780262039956.
- "Structure et cinematique de l'univers local par HELENE DI NELLA". theses.fr. Retrieved 1 December 2017.
- "El mapa completo del Universo exhibe las galaxias reunidas como un capullo de seda". El País (in Spanish). 14 July 1994. Retrieved 1 December 2017.
- Kruesi, Liz (21 November 2017). "Hidden Supercluster Could Solve Milky Way Mystery". Quanta Magazine. Retrieved 1 December 2017.
- "Poussée par un vide, notre galaxie surfe à plus de 2 millions de km/h - Communiqués et dossiers de presse - CNRS" (in French). CNRS. Retrieved 31 January 2017.
- "Nomination à l'Institut Universitaire de France" (in French). IP2I. Retrieved 1 October 2019.
- "Liste des partenaires du planétarium de Vaulx-en-Velin" (in French). planetariumvv.com. Retrieved 14 November 2014.
- "Le Planétarium est fier de sa marraine, Hélène Courtois" (in French). leprogres.fr. 9 September 2014. Retrieved 14 November 2014.
- "Distinction honorifique à l'IPNL" (in French). IP2I. Retrieved 1 October 2019.
- "USTH signs MoU with Claude Bernard University Lyon 1" (Press release). University of Science and Technology of Hanoi. 12 October 2017. Retrieved 1 December 2017.
- "Décret du 31 décembre 2019 portant promotion et nomination dans l'ordre national de la Légion d'honneur" (PDF). LÉGION D’HONNEUR. 2020-01-01. Retrieved 2020-01-02.