David Elbaz (born March 18, 1966) is a French observational astrophysicist specializing in

galaxy formation and evolution In cosmology, the study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the process ...

. He is a Research Director at the Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA-Saclay), where he has worked as a researcher in the Astrophysics Division (AIM) since 1994. He led the Cosmology and Evolution of Galaxies laboratory for approximately a decade and has been the managing editor of the journal ''

Astronomy & Astrophysics ''Astronomy & Astrophysics (A&A)'' is a monthly peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. It is operated by an editorial team under the supervision of a board of directors re ...

'' since 2018.

Biography

Elbaz's grandparents moved to France from

Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...

at the beginning of the 20th century. He was born and raised in the

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

area. He attended the École Nationale Supérieure de Physique (ENSPG) in

Grenoble Grenoble ( ; ; or ; or ) is the Prefectures in France, prefecture and List of communes in France with over 20,000 inhabitants, largest city of the Isère Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region ...

, where he obtained an engineering degree in 1990. He completed his

PhD A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...

in Astrophysics in 1994 at the Université Joseph Fourier in Grenoble with a thesis entitled "Origine du fer dans le milieu intra-amas et distribution du gaz X dans les amas de galaxies". His supervisors were James Lequeux and Monique Arnaud. In 2005, he was awarded a

habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in Germany, France, Italy, Poland and some other European and non-English-speaking countries. The candidate fulfills a university's set criteria of excelle ...

from the

Paris-Sud University Paris-Sud University (), also known as the University of Paris — XI (or as the Orsay Faculty of Sciences, University of Paris before 1971), was a French research university distributed among several campuses in the southern suburbs of Paris, ...

. Elbaz has supervised 14

postdoctoral researcher A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). Postdocs most commonly, but not always, have a temporary acade ...

s and 7 PhD students, two of whom received awards for their dissertations: H. Aussel (1999) and C. Schreiber (2015). He has been teaching the ''Galaxy Evolution'' course in the Masters program entitled ''Recherche Astronomie, Astrophysique et Ingénierie Spatiale de Paris'' since 2005.

Research areas

Elbaz has made contributions in observational extragalactic astrophysics through space

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

and

submillimeter Submillimetre astronomy or submillimeter astronomy (see spelling differences) is the branch of observational astronomy that is conducted at submillimetre wavelengths (i.e., terahertz radiation) of the electromagnetic spectrum. Astronomers plac ...

observations. He has been recognized as an ISI Highly Cited researcher by

Clarivate Analytics Clarivate Plc is a British-American publicly traded analytics company that operates a collection of subscription-based services, in the areas of bibliometrics and scientometrics; business and market intelligence, and competitive profiling ...

. In 2001, using new data from the

Infrared Space Observatory The Infrared Space Observatory (ISO) was a space telescope for infrared light designed and operated by the European Space Agency (ESA), in cooperation with ISAS (now part of Japan Aerospace Exploration Agency, JAXA) and National Aeronautics and ...

, Elbaz and Ranga Chary produced a suite of galaxy spectral energy distribution templates. Along with the current knowledge of the galaxy

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

distribution, they were able to interpret the cosmic infrared background as being produced to at least 70% level from dust-enshrouded

star formation Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, sta ...

in luminous infrared galaxies. The advent of the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003, that was deactivated when operations ended on 30 January 2020. Spitzer was the third space telescope dedicate ...

in 2003 enabled extremely deep observations in the mid-infrared field. Elbaz and his collaborators analyzed observations from the Great Observatories Origins Deep Survey and demonstrated that the star formation rate of individual galaxies increases due to environmental effects up to a critical galaxy density at redshift one, above which it decreases again, concluding that it suggests that galaxy evolution is not independent from structure formation at larger scales in the

universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...

. Five years later, using deep far infrared observations from the

Herschel Space Observatory The Herschel Space Observatory was a space observatory built and operated by the European Space Agency (ESA). It was active from 2009 to 2013, and was the largest infrared telescope ever launched until the launch of the James Webb Space Telesco ...

, Elbaz led a study, writing that

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar Sys ...

across cosmic time form

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

s in two main modes: one placing them in the "main sequence", where their star formation rate correlates tightly with their

stellar mass Stellar mass is a phrase that is used by astronomers to describe the mass of a star. It is usually enumerated in terms of the Sun's mass as a proportion of a solar mass (). Hence, the bright star Sirius has around . A star's mass will vary over ...

, and the other where the galaxies are more compact and form stars more efficiently departing from this correlation. Using observations from

ALMA Alma or ALMA may refer to: Arts and entertainment * ''Alma'' (film), a 2009 Spanish short animated film * ''Alma'', an upcoming film by Sally Potter * ''Alma'' (Oswald de Andrade novel), 1922 * ''Alma'' (Le Clézio novel), 2017 * ''Alma'' ( ...

, his group also discovered a dominant population of optically invisible massive galaxies in the early universe.

Awards

Elbaz has received several awards, including: * Chrétien Award of the

American Astronomical Society The American Astronomical Society (AAS, sometimes spoken as "double-A-S") is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC. The primary objective of the AAS is to promote the adv ...

(2000) * Prix Jaffé from the Foundation of the

Institut de France The ; ) is a French learned society, grouping five , including the . It was established in 1795 at the direction of the National Convention. Located on the Quai de Conti in the 6th arrondissement of Paris, the institute manages approximately ...

(2017) * Member of the

Academia Europaea The Academia Europaea is a pan-European Academy of humanities, letters, law, and sciences. The Academia was founded in 1988 as a functioning Europe-wide Academy that encompasses all fields of scholarly inquiry. It acts as co-ordinator of Europe ...

(2019)

Administrative duties

Elbaz's duties in the astrophysics' community include: * Managing Editor of ''

'', 2018–present * Member of the ESA SPICA Science Team, 2018–2021 * Member of the Euclid France steering committee, 2013–present * Member of the ESA Astronomy Working Group, 2015–2018 * President of the International Space Advisory Board for the SPICA satellite for

JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into o ...

, 2015–2016

Public outreach

Elbaz has been interviewed on various topics of modern astrophysics by French media, including ''

Le Monde (; ) is a mass media in France, French daily afternoon list of newspapers in France, newspaper. It is the main publication of Le Monde Group and reported an average print circulation, circulation of 480,000 copies per issue in 2022, including ...

'',

France Culture France Culture () is a French public radio channel and part of Radio France Radio France () is the French national public radio broadcaster. Stations Radio France offers seven national networks: *France Inter — Radio France's "generalist ...

, and '' Sciences et Avenir''. He has written scenarios and participated in shows that involve science and art that have been presented in various theaters in France, including: * "La tête dans les étoiles" (with the

neurobiologist A neuroscientist (or neurobiologist) is a scientist specializing in neuroscience that deals with the anatomy and function of neurons, neural circuits, and glia, and their behavioral, biological, and psychological roles in health and disease. ...

Alain Destexhe and the magician Marc Feld) * "Magicosmologie" (with Marc Feld) * "Jonglerie Astrale" (with the

juggler Juggling is a physical skill, performed by a juggler, involving the manipulation of objects for recreation, entertainment, art or sport. The most recognizable form of juggling is toss juggling. Juggling can be the manipulation of one object o ...

Vincent de Lavenère) Elbaz has authored several science books: * ''A la recherche de l'univers invisible: matière noire, énergie sombre, trous noirs'', 2016, Odile Jacob; it received the "Prix Sciences et Philosophie" in 2017. *''Αναζητώντας το αόρατο σύμπαν: σκοτεινή ύλη, σκοτεινή ενέργεια, μαύρες τρύπες'', 2021, Crete University Press. * ''Le vase de Pépi'', 2007, Odile Jacob. * ''...et Alice Tao se souvint du futur'', 2010, Odile Jacob. *''La plus belle ruse de la lumière'', 2021, Odile Jacob.

References

External links

Official YouTube channel
{{DEFAULTSORT:Elbaz, David 1966 births Living people French astrophysicists French Alternative Energies and Atomic Energy Commission Members of Academia Europaea Scientists from Paris