T.Shenar [at] uva.nl
tomer.shenar [at] gmail.com
TOMER SHENAR
TOMER SHENAR
stellar astrophysicist
An artist's impression of VFTS 243, the first unambiguous dormant stellar-mass black hole detected outside our Galaxy
Shenar et al. 2022, Nature Astronomy
Image credit: ESO/L. Calçada
(taken from an article in "The Guardian")
My name is Tomer Shenar, born in 1986 in Israel. My research focuses on massive stars. Today, we know that the vast majority of massive stars interact with companion stars during their lifetime: My research is dedicated to study this interaction and its implication on stellar evolution.
I collect and use multi-wavelength spectroscopic, photometric, and interferometric data with the world's largest telescopes to infer the observational properties of massive stars and binaries in the Local Group. I develop and utilise state-of-the-art model atmospheres and spectral disentangling algorithms to derive robust constraints on the progenitors of compact objects (Wolf-Rayet stars, OB-type stars, stripped stars), with the goal of advancing our understanding of the evolution of massive stars and binaries and the production of gravitational-wave sources. I am a co-developer of the Potsdam Wolf-Rayet (PoWR) code.
2007-2010: BSc in Mathematics & physics, Technion, Israel
2011-2013; MSc in Physics, Uni. Potsdam, Germany
2013-2017; PhD, Uni. Potsdam, Germany
2017-2018: Postdoc, Uni. Potsdam, Germany
2018 - 2021: Postdoc, KU Leuven, Belgium
2021 - now: Marie-Curie fellow, Uni. Amsterdam, NL
2021 - now (suspended): FWO postdoc fellow, KU Leuven, Belgium
Skills
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Observations with world's largest observatories: ((e.g., Hubble STIS, COS; ESO UVES,X-SHOOTER,GRAVITY)
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Spectral disentangling (Fourier & wavelength space) of binaries and multiple systems
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Quantitative spectroscopy of Galactic and extragalactic Wolf-Rayet, Be, OB-type, and binary-stripped stars and binaries
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Wind analysis: mass-loss, clumping, wind-wind collisions
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Orbital analyses
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Development of model atmosphere codes; radiative transfer in expanding atmospheres (PoWR code)
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Interpretation of multi-wavelength spectra from X-ray to infrared
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Statistical comparisons with evolution models (MESA, BPASS, Bonn)
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Teaching and supervising of BSc, MSc, and PhD students
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FORTRAN // C // Python // IDL // LINUX // LaTeX // Mathematica
Research interests
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The evolution of massive single and binary stars across cosmic times.
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Formation of gravitational-wave progenitors from binaries at different metallicities
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Properties of the first stars
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Formation of Wolf-Rayet stars (as single stars and binaries) at different metallicities
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Evolution of the most massive stars; the upper-mass limit
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Origin of Be stars
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Occurrence of binary-stripped stars
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Stellar feedback
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Magnetism in massive stars
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Origin of X-rays in massive stars;
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X-ray binaries
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Detection of black holes in stellar binaries
PhD & MSc students
PhD: Karan Dsilva
KU Leuven
Karan takes a modern look at the Galactic Wolf-Rayet stars and tries to understand how they evolved.
WC binaries:
Dsilva, Shenar et al. 2020, A&A, 641, 26
WN binaries:
Dsilva, Shenar et al. 2022, A&A, in press
PhD: Julila Bodensteiner
KU Leuven
Julia searches for post-interaction binaries in clusters.
Julia finds a clear excess of Be stars in evolved clusters. Together with Julia, we also found some very cool Be stars (confused as black holes) hiding not far away from us!
MSc + PhD: Soetkin Janssens
KU Leuven
Soetkin analysed a highly complex Wolf-Rayet "binary" in the Large Magellanic Cloud. "Binary", because she found it's a quadruple or quintuple system, hosting one of the most massive contact systems known
Jannsens, Shenar et al. 2020, A&A, 646, 33
Soetkin now continues her PhD under my co-supervision with the goal of hunting for black holes with Gaia -- check out her 1st PhD paper: Janssens, Shenar et al. 2022, A&A, 658, 129
MSc: Roel Lefever
KU Leuven
The majority of Wolf-Rayet analyses assume a fixed wind velocity law. Roel performed a quantitative investigation of alternative velocity laws and their impact on the spectral appearance of Wolf-Rayet stars and their inferred stellar parameters, with important implications on the properties of black-hole progenitors.
Check out his upcoming publication (Lefever, Shenar et al. submitted)
MSc: Sancho Luijten
University of Amstedam
Sancho will be analysing multi-epoch data acquired with the UVES@ESO spectrograph (PI: Shenar), targeting two very unique WR binaries. These binaries were proposed to host not one, but two Wolf-Rayet stars, and hence potentially correspond to a rare evolutionary phase prior to black-hole + black-hole binary formation.
Stay tuned!
MSc: Ardra Ramachandran
University of Amstedam
Ardra was selected through a competitive process to participate in the ASPIRE summerschool at the Uni. Amsterdam. Her goal? Re-deriving the orbital solution a famous "dormant" black hole in our Galaxy, MWC 656.
Guess what? She found that the unseen companion weighs between 0.7-3 Msun, and hence very unlikely to be a black hole.
MSc: Freek Temming
University of Amsterdam
Freek will be working on new data acquired with the X-SHOOTER instrument @ VLT to establish the binary properties and physical properties of the WC population.
Stay tuned!
WHY ASTROPHYSICS?
My fascination for the universe has never left me ever since taking part in an astronomical event in the Negev, a desert in the southern region of Israel, at the age of 14. I learned that all these thousands of bright points in the night sky were suns, much like our own, but in different shapes and sizes. That day I realized that my connection with the stars would accompany me for the rest of my life.
Through my work, I hope to advance our understanding of stars, and inspire young, curious pupils and students to investigate the Universe we live in.
Fellowships & third-party funding
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Jun. 2021: 3-year senior FWO fellowship (PI)
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Feb. 2021: 2-yr Marie Skłodowska-Curie Individual fellowship (PI)
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Feb 2019: funding by the ChETEC COST action (PI)
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Aug. 2019: 4-yr FWO PhD fellowship (scientific PI and co-supervisor)
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Sep. 2018: ERC-funded position (formal PI: Prof. Hugues Sana)
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Oct. 2016: DLR-funded
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Jan. 2013: Richard-Winter scholarship for excellency
Prizes & awards:
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Jun. 2021: KU Leuven's Research Council Award
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Mar. 2018; Horizon 2020 Seal of excellence
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Oct. 2017: Carl-Ramsauer award, Berlin Physics society
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Jan. 2017: graduated summa cum laude
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Sep. 2016: visit at the MIT, funded by the Chandra visitor program
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Jul 2014: Physics thesis award, Berlin physical society
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Jul. 2013: Award for outstanding achievements of international students, DAAD
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3-year senior FWO fellowship (PI)
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4-yr FWO PhD fellowship (scientific PI and co-supervisor
PUBLIC OUTREACH
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Skype-a-Scientist (www.skypeascientist.com)
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Activities in kindergartens: Introduction to our solar system
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Mentoring of pupils in astronomy-related projects, at the University of Potsdam, Germany
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Physics & Maths tutoring of pupils with socially or economically disadvantaged background (Elele center, Berlin)
Introducing the children to the solar system
The children draw their own impression of the solar system
The kids "pretended" to be planets revolving around the sun - lots of fun!
The kids were inspired by real pictures and simulations of planets, stars, and galaxies
PRIVATE
When I'm not doing science, I read, play the guitar & piano, and I love to sing. I play adventure games, dance, or just hang out with my dear ones. More about me over a beer (or two)!