Dark Matter revealed by the First Stars

Link to Video Explanation: In English or In Hebrew

2016 - present   Head of the Department of Astrophysics, Tel Aviv University
2015 - present   (Full) Professor, Tel Aviv University
2016   Visiting Professor, The Perimeter Institute, Waterloo, Canada
2015 - 2016   Leverhulme Visiting Professor, and Visiting Fellow of Mansfield College, University of Oxford, UK
2015   Lagrange Award winner, Institut D'Astrophysique de Paris (IAP), France
2009 - 2015   Associate Professor, Tel Aviv University
2008 (Spring)   Moore Distinguished Scholar, Caltech
2007 (Fall)   Visiting Associate Professor, ICRR, University of Tokyo
2001 - 2009   Senior Lecturer, Tel Aviv University (2006: Tenured)
2015-16   Visiting Fellowship, Mansfield College, University of Oxford (UK)
2015   Leverhulme Visiting Professorship, Leverhulme Trust (UK) [link]
2015   Lagrange Award, Institut Lagrange de Paris (ILP), France [link]
2007 - 2008   Fellowship, John Simon Guggenheim Memorial Foundation [link]
2008   Moore Distinguished Scholar, Caltech
2007 - 2008   Radcliffe Institute Fellowship, Harvard (declined) [link]
2001 - 2004   Alon Fellowship, Israeli Council of Higher Education

Research grants:
2017 - 2020   Israel - China (ISF - NSFC) grant (with Chinese collaborators)
2017 - 2019   Templeton Foundation grant
2012 - 2015   Israel Space Agency grant (with Yoel Rephaeli)
2009 - 2012   U.S. National Science Foundation Grant (PI: Judd Bowman)
2009 - 2013   Israel Science Foundation Grant
2005 - 2010 (frozen 2007/8)   U.S.-Israel Binational Science Foundation Grant (with Avi Loeb)
2005 - 2008   Israel Science Foundation Grant
2002 - 2005   Israel Science Foundation Grant
2002 - 2005   U.S. National Science Foundation Grant (PI: Avi Loeb)
2003   NATO Grant (with Avi Loeb)
2018   Co-organizer of "Cosmological Signals from Cosmic Dawn to the Present", Aspen Winter Conference on Astrophysics [link]
2015   Principal organizer of "Cosmology and First Light", an international conference at the Institut D'Astrophysique de Paris (IAP) [link]
2014 -   Member of SKA (Square Kilometre Array) Science Working Group and Key Science Project on the Epoch of Reionization and Cosmic Dawn
2014 - 2015   Member of International Ph.D. Board of Scuola Normale Superiore, Pisa, Italy
2010   Principal organizer, Aspen Winter Astrophysics Conference on "The High Redshift Universe: A Multi-Wavelength View" [link]
2008   Scientific Organizing Committee, 23'rd IAP (Paris) Colloquium
2007   Space Telescope Science Institute, Review Panel of Hubble Space Telescope proposals
2006   Principal organizer, John Bahcall Physics Day (Tel Aviv University) [link]
2006   Principal organizer, Aspen Winter Astrophysics Conference on "Cosmological Probes of Baryons and Dark Matter" [link]
Invited conference talks:
2017   Post Planck Cosmology: Enigma, Challenges and Visions, Pune, India
2017   Fundamental Physics with the Square Kilometre Array, Mauritius
2016   SKA 2016: Science for the SKA Generation (general conference + Key Science Project meeting), Goa, India
2016   CMB Spectral Distortions from Cosmic Baryon Evolution, Raman Research Institute, Bangalore, India
2016   Cosmological Probes of Fundamental Physics, Weizmann Institute of Science, Israel
2016   Physics of Reionization and the Cosmic Dawn in the SKA Era, Sexten Center for Astrophysics, Sesto, Italy
2015   SKA CD/EoR Science Team Workshop (invitation-only conference for developing the science team for Cosmic Dawn / Epoch of Reionization measurements with the Square Kilometre Array), Groningen, the Netherlands
2015   RESCEU APCosPA (Asia Pacific Organization for Cosmology and Particle Astrophysics) Summer School on Cosmology and Particle Astrophysics (Invited lecture series), Tokyo, Japan
2015   The SKA Key Science Workshop (invitation-only conference for developing scientific plans for the Square Kilometre Array), Stockholm, Sweden
2014   CASCA (Canadian Astronomical Society) Annual Meeting, Quebec City, Canada
2012   "Gamma Ray Bursts in the Era of Rapid Follow-up", Liverpool, UK
2012   CosmoBias: International Meeting on "Physical Bias in Cosmology" (Invited Review), Marseille, France
2011   "Hydrogen Cosmology" workshop at Harvard
2008   Harvard University Conference on "21cm Cosmology"
2008   "Cosmology with the CMB and LSS", School and workshop program, Tata Institute of Fundamental Research, India (Invited lecture series; could not attend)
2007   Workshop: "Early universe and physics beyond the standard model", Tokyo, Japan
2007   "HI Survival through Cosmic Times", Tuscany, Italy
2006   "From Planets to Galaxies", Budapest, Hungary
2004   Oort Workshop on "CMB and first objects at the end of the dark ages: observational consequences of reionization", Holland
2003   Kloster Irsee Workshop on "The Formation and Early Evolution of Galaxies", Germany
2002   "Early Cosmic Structures and the End of the Dark Ages", Elba, Italy
2001   Annual Meeting of the Israeli Physics Society, Tel Aviv, Israel
2000   Harvard University Conference on "The First Generation of Cosmic Structures"

Contributed conference talks:
2015   Cosmology and First Light, IAP, Paris, France
2014   CosPA 2014: 11th International Symposium on Cosmology & Particle Astrophysics, Auckland, New Zealand
2013   CosPA 2013: 10th International Symposium on Cosmology & Particle Astrophysics, Hawaii, U.S.A.
2010   CITA@25/Bond@60: The Theory of the Universe and Everything in It, Toronto, Canada
2010   The High Redshift Universe: A Multi-Wavelength View, Aspen, U.S.A.
2009   Focus week on non-Gaussianities in the sky, Tokyo, Japan
2006   Cosmological Probes of Baryons and Dark Matter, Aspen, U.S.A.
2005   Reionizing the Universe, Groningen, The Netherlands
2004   Galaxy-Intergalactic Medium Interactions, KITP, Santa Barbara, U.S.A.
2004   The Large Scale Structure of Gas and Mass in the High Redshift Universe, Technion, Israel
2004   The Large-Scale Distribution of Mass&Light in the Universe, Aspen, U.S.A.
2003   Stars and Structure Formation: From First Light to the Milky Way, Zurich, Switzerland
2003   Galaxy Formation, Jerusalem, Israel
2003   The Baryonic Universe, Aspen, U.S.A.
2000   The Physics of Galaxy Formation, Tsukuba, Japan
1999   Gravitational Lensing: Recent Progress and Future Goals, Boston, U.S.A.
1999   Cosmological Implications of the Local Group, Aspen, U.S.A.
Currently Looking for Students and Postdocs
[Press for full info]

Ph.D.   Smadar Naoz: "The First Generation of Galaxies and 21-cm Fluctuations", 2009. Postdoc positions: Northwestern University; Harvard ITC Fellow; Einstein Fellow. Faculty: Assistant Professor at UCLA, 2015 Sloan Fellow [website]
Ph.D.   Anastasia Fialkov: 21-cm Cosmology, 2011 - 2013 (Ph.D. jointly advised with Nissan Itzhaki). Postdoc positions: Junior Research Chair at École Normale Supérieure, Paris; Harvard ITC Fellow [website]
Ph.D.   Aviad Cohen: 21-cm Cosmology, M.Sc., 2013 - (2014: joined direct Ph.D. program).
Ph.D.   Eli Visbal: 21-cm Cosmology, 2011 - 2013 (While not formally my student, this Harvard graduate student's summer project with me became a Nature paper and an important part of his thesis). Postdoc: Columbia University.
Ph.D.   Doron Lemze (jointly advised with Tom Broadhurst and Yoel Rephaeli): "Modeling clusters and starburst galaxies", 2010. Postdoc: Johns Hopkins University.
Postdoc   Andrea Morandi: 21-cm Cosmology, 2010 - 2012 (2 years).
M.Sc.   Shay Noter: "Halo Statistics - A New Alternative to Simulations", M.Sc., 2007.
M.Sc.   Oren Zoran: "A Cosmic Relation between Extinction and Star Formation", M.Sc., 2006.
Postdoctoral positions:
2000 - 2001   Postdoctoral Fellow, Canadian Institute for Theoretical Astrophysics (Toronto)
1997 - 2000   Postdoctoral Member, Institute for Advanced Study (Princeton)

1997 Ph.D. in Physics; Massachusetts Institute of Technology (M.I.T.)
1993 B.A. in Math and Physics (Summa Cum Laude, with Honors in both majors); University of Pennsylvania

Personal information:
1973 Born in Haifa, Israel
Citizenship: U.S. and Israel
Married to Riki and father to Or and Ariel
Research Interests:
Theoretical Astrophysics and Cosmology: 21-cm cosmology, formation of the first stars and quasars, cosmic dawn and cosmic reionization, dark matter, galaxy formation, large-scale structure, and gravitational lensing.

Key Publications (chronological order):
  • ``The rise of the first stars: Supersonic streaming, radiative feedback, and 21-cm cosmology'', Rennan Barkana, Physics Reports (Invited Review), 645, 1 (2016) [link] .
  • "Large-Scale Distribution of Total Mass versus Luminous Matter from Baryon Acoustic Oscillations: First Search in the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey Data Release 10", Maayane Soumagnac, Rennan Barkana, C. G. Sabiu, A. Loeb, A. J. Ross, F. B. Abdalla, S. T. Balan, and O. Lahav, Physical Review Letters , 116, 201302 (2016) [link].
  • "Reconstructing the nature of the first cosmic sources from the anisotropic 21-cm signal", Anastasia Fialkov, Rennan Barkana, and Aviad Cohen, Physical Review Letters , 114, 101303 (2015) [link].
  • "The observable signature of late heating of the Universe during cosmic reionization", Anastasia Fialkov, Rennan Barkana, and Eli Visbal, Nature , 506, 197 (2014) [link].
  • "The signature of the first stars in atomic hydrogen at redshift 20", Eli Visbal, Rennan Barkana, Anastasia Fialkov, Dmitriy Tseliakhovich, and Chris Hirata, Nature , 487, 70 (2012) [link].
  • "The First Stars in the Universe and Cosmic Reionization", Rennan Barkana, Science (Invited Review), 313, 931 (2006).
  • "Detecting the Earliest Galaxies Through Two New Sources of 21cm Fluctuations", Rennan Barkana and Abraham Loeb, The Astrophysical Journal , 626, 1 (2005).
  • "A Method for Separating the Physics from the Astrophysics of High-Redshift 21cm Fluctuations", Rennan Barkana and Abraham Loeb, The Astrophysical Journal Letters, 624, 65 (2005).
  • "Unusually Large Fluctuations in the Statistics of Galaxy Formation at High Redshift", Rennan Barkana and Abraham Loeb, The Astrophysical Journal , 609, 474 (2004).
  • "Spectral Signature of Cosmological Infall Around the First Quasars", Rennan Barkana and Abraham Loeb, Nature , 421, 341 (2003) [link] .
  • ``In the Beginning: The First Sources of Light and the Reionization of the Universe'', Rennan Barkana and Abraham Loeb, Physics Reports (Invited Review), 349, 125 (2001) [link] .
  • ``Fuzzy Cold Dark Matter: The Wave Properties of Ultralight Particles'', Wayne Hu, Rennan Barkana and Andrei Gruzinov, Physical Review Letters , 85, 1158 (2000).
The full, up-to-date listing of my publications in ADS, including (and ordered by) citations, is here.


69% Complete (info)
26% Complete (success)
GAS 5%
5% Complete (warning)
DM radio sky


In recent decades, the biggest discoveries in physics have come from astronomy (dark matter, dark energy, gravitational waves, and black holes). We recently (March 2018) announced an exciting potential discovery that may represent another example of deriving fundamental physics from astronomical observations.

Astronomers have been searching for a radio-wave signal that had been predicted to be a sign of the formation of the first stars in the early Universe. Bowman and colleagues reported the first such detection, obtained with their EDGES radio telescope. The signal had a much larger amplitude than expected, presenting a puzzle. I realized that this surprising signal can be explained by combining two factors: the first stars, and dark matter. The first stars in the universe turned on the radio signal as expected, while the dark matter collided with the ordinary matter and cooled it down. Extra-cold material naturally explains the strong radio signal.

If true, this has enormous implications in answering one of the most basic questions: What is the Universe made of? Indeed, this is the first direct clue about the nature of the mysterious dark matter that makes up most of the matter in the Universe. For example, physicists expected that dark matter would be made up of heavy particles, but the discovery indicates low-mass particles.

Some caution is needed, since the EDGES measurement is the first of its kind. Independent confirmation is now being attempted, and much more information is expected within a few years. I predict that the dark matter produced a specific pattern of radio waves on the sky (the image above or to the left of this text is an example), which can be detected with a large array of radio antennas. One such array is the SKA, the largest radio telescope in the world, now under construction. Such an observation with the SKA would confirm that the first stars have indeed revealed the dark matter.

Discovery (English)

Dark Matter Revealed by the First Stars, Prof. Rennan Barkana (English version)

Link to the Video


Dark Matter Revealed by the First Stars, Prof. Rennan Barkana (Hebrew version)

Link to the Video

Intro to Field

The First Stars (prior to the March 2018 discovery), Prof. Rennan Barkana (Hebrew with English subtitles)

Link to the Video

Favorite Quotes

Quotes from Feynman, Einstein, and many others

Link to Quotes page


My courses at Tel Aviv University

Link to Teaching page


My tribute to Shostakovich

Link to Shostakovich page

Research and Outreach Links:
Research highlight (2014): Cosmic heating and early black holes (Nature): Link.
Research highlight (2012): The First Stars at Redshift 20 (Nature): Link.
A news article (2009) in Science on 21-cm cosmology: Link, PDF.
Media appearances on gravity waves from inflation (in Hebrew): Link.
Radio Interview in Hebrew on the Cosmic Microwave Background (4.38 MB, 6:23 min, MP3).
Popular Lecture in Hebrew on Cosmology (81 min video + power point lecture).
Prof. Rennan Barkana
Head, Department of Astrophysics
School of Physics and Astronomy
Tel Aviv University
Tel Aviv, 6997801
Office: Kaplun 111
Cell Phone: 972-526-313116
Office Phone: 972-3-6405993
Fax: 972-3-6408179
Secy: 972-3-6407414 (Daniella)
email: barkana@tau.ac.il [send]