Przemek Mróz

Postdoctoral scholar in astronomy

I am a postdoc in the Caltech Department of Astronomy working under the supervision of Prof. Shrinivas Kulkarni. Originally from Poland, I received my PhD from University of Warsaw where I was working with Prof. Andrzej Udalski. I am a member of the ZTF and OGLE teams. My research interests include gravitational microlensing, Milky Way structure and history, transients, and variable stars. I have a large experience in analyzing huge photometric data sets using both traditional and machine-learning-based techniques.
Here's the list of my publications and my CV.

Research projects and publications

Free-floating planets

Theories of planet formation and evolution predict the existence of free-floating planets, gravitationally unattached to any star. I use gravitational microlensing to detect free-floating planets and study their population in the Milky Way.

  • Mróz, P., Poleski, R., Gould, A., et al. A terrestrial-mass rogue planet candidate detected in the shortest-timescale microlensing event, ApJL, 903, 11 (2020)
  • Ryu, Y.-H., Mróz, P., Gould, A., et al. KMT-2017-BLG-2820 and the Nature of the Free-Floating Planet Population, arXiv:2010.07527 (2020)
  • Mróz, P., Poleski, R., Han, C., et al. A free-floating or wide-orbit planet in the microlensing event OGLE-2019-BLG-0551, AJ, 159, 262 (2020)
  • Mróz, P., Udalski, A., Bennett, D.P., et al. Two new free-floating or wide-orbit planets from microlensing, A&A, 622, A201 (2019)
  • Mróz, P., Ryu, Y.-H., Skowron, J, et al. A Neptune-mass Free-floating Planet Candidate Discovered by Microlensing Surveys, AJ, 155, 121 (2018)
  • Mróz, P., Udalski, A., Skowron, J., et al. No large population of unbound or wide-orbit Jupiter-mass planets, Nature, 548, 183 (2017)

Machine learning

I am interested in using modern machine learning techniques for solving astrophysical problems.

  • Mróz, P. Identifying microlensing events using neural networks, Acta Astron., 70, 169 (2020)

Modeling gravitational microlensing events

Gravitational microlensing enables one to detect dark and cold objects that are nearly impossible to detect othewise. I am an expert in modeling the light curves of microlensing events.

  • Wyrzykowski, Ł., Mróz, P., Rybicki, K., et al. Full orbital solution for the binary system in the northern Galactic disk microlensing event Gaia16aye, A&A, 633, A98 (2020)
  • Mróz, P., Udalski, A., Bond, I.A., et al. OGLE-2013-BLG-0132Lb and OGLE-2013-BLG-1721Lb: Two Saturn-mass Planets Discovered around M-dwarfs, AJ, 154, 205 (2017)
  • Mróz, P., Han, C., Udalski, A., et al. OGLE-2016-BLG-0596Lb: A High-mass Planet from a High-magnification Pure-survey Microlensing Event, AJ, 153, 143 (2017)

Modeling the structure of the Milky Way and Magellanic Clouds

I use a variety of tracers (variable stars, microlensing events) to study the structure and history of the Milky Way and Magellanic Clouds.

  • Mróz, P., Udalski, A., Szymański, M.K., et al. Microlensing optical depth and event rate in the OGLE-IV Galactic plane fields, ApJS, 249, 16 (2020)
  • Skowron, D.M., Skowron, J., Mróz, P., et al. A three-dimensional map of the Milky Way using classical Cepheid variable stars, Science, 365, 478 (2019)
  • Mróz, P., Udalski, A., Skowron, J., et al. Microlensing optical depth and event rate toward the Galactic bulge from eight years of OGLE-IV observations, ApJS, 244, 29 (2019)
  • Mróz, P., Udalski, A., Skowron, D.M., et al. Rotation curve of the Milky Way from Classical Cepheids, ApJL, 870, 10 (2019)
  • Mróz, P. & Poleski, R. New Self-lensing Models of the Small Magellanic Cloud: Can Gravitational Microlensing Detect Extragalactic Exoplanets?, AJ, 155, 154 (2018)
  • Jacyszyn-Dobrzeniecka, A., Skowron, D.M., Mróz, P., et al. OGLE-ing the Magellanic System: Three-Dimensional Structure of the Clouds and the Bridge Using RR Lyrae Stars, Acta Astron., 67, 1 (2017)
  • Jacyszyn-Dobrzeniecka, A., Skowron, D.M., Mróz, P., et al. OGLE-ing the Magellanic System: Three-Dimensional Strucytre of the Clouds and the Bridge Using Classical Cepheids, Acta Astron., 66, 149 (2016)

Variable stars

  • Mróz, P., Udalski, A., Pietrukowicz, P., et al. The awakening of a classical nova from hibernation, Nature, 537, 649 (2016)
  • Mróz, P., Udalski, A., Poleski, R., et al. OGLE Atlas of Classical Novae. II. Magellanic Clouds, ApJS, 222, 9 (2016)
  • Mróz, P., Udalski, A., Poleski, R., et al. OGLE Atlas of Classical Novae. I. Galactic Bulge Objects, ApJS, 219, 26 (2015)

Author and coauthor of 183 refereed publications, including 18 as the first author and 5 in Nature/Science (2 as the first author). Author of 22 ATels. Total number of citations: 3849 (according to the SAO/NASA Database). My H-index is 34 (according to the SAO/NASA Database).


2019 - present

Postdoctoral scholar in astronomy

California Institute of Technology, USA

02/2019 - 05/2019

Visiting Student Researcher

IPAC, California Institute of Technology, USA

2015 - 2019

Ph.D. in Astronomy

University of Warsaw, Poland

2013 - 2015

M.Sc. in Astronomy

University of Warsaw, Poland

2010 - 2013

B.Sc. in Astronomy

University of Warsaw, Poland

Grants and awards

  • 2020: Nicolaus Copernicus Award of the Polish Academy of Arts and Sciences
  • 2020: Polish Prime Minister Prize for Remarkable Scientific Achievements
  • 2020: Frank Wilczek Award
  • 2020: International Astronomical Union PhD Prize
  • 2020: NASA TESS Guest Investigator Program (project: Discovering black holes in detached binary systems)
  • 2018: ETIUDA scholarship of the Polish National Science Center (project: Astrophysical applications of gravitational microlensing in the Milky Way)
  • 2018: START fellowship of the Foundation for Polish Science (with distinction)
  • 2017: Polish Astronomical Society Young Scientist Award
  • 2016: Bardadin-Otwinowska Award for the best original M.Sc. thesis prepared at the Faculty of Physics, University of Warsaw
  • 2014: "Diamond Grant" of the Polish Ministry of Science and Higher Education
  • 2010: Absolute Winner of the 4th International Olympiad on Astronomy and Astrophysics, Beijing, China
  • 2009: Gold Medal in the 3rd International Olympiad on Astronomy and Astrophysics, Tehran, Iran


Seminar presentations

  • 04/2021: Ohio State University, Columbus, OH, USA
  • 03/2021: Astronomical Observatory, University of Warsaw, Warszawa, Poland
  • 01/2021: University of Birmingham, Birmingham, UK
  • 11/2020: National Centre for Nuclear Research, Warszawa, Poland
  • 10/2020: Astronomical Observatory, Jagiellonian University, Kraków, Poland
  • 07/2019: Heidelberg University, Heidelberg, Germany
  • 04/2019: IPAC, California Institute of Technology, Pasadena, CA, USA
  • 04/2019: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
  • 01/2019: Institute of Physics, Jagiellonian University, Kraków, Poland
  • 12/2018: Institute of Astronomy, University of Wrocław, Wrocław, Poland
  • 11/2018: Tsinghua Center for Astrophysics, Tsinghua University, Beijing, China
  • 05/2018: Astronomical Observatory of Adam Mickiewicz University, Poznań, Poland
  • 05/2018: Canada-France-Hawaii Telescope Institute, Hawaii, USA

Conferences, Workshops, & Schools (selected)

  • 02/2021: GRAVITY+ Community Workshop, online
  • 01/2021: 11th OPTICON Gaia Science Alerts workshop, online
  • 11/2020: Exoplanet Demographics, Pasadena, CA, USA
  • 01/2019: 23rd International Microlensing Conference, New York City, NY, USA
  • 04/2018: European Week of Astronomy and Space Science 2018, Liverpool, UK
  • 03/2018: Life on Earth and beyond: emergence, survivability, and impact on the environment, Bertinoro, Italy
  • 01/2018: 22nd International Microlensing Conference, Auckland, New Zealand
  • 09/2017: 38th Polish Astronomical Society Assembly, Zielona Góra, Poland
  • 07/2017: Celebrating 25 years of the OGLE project, Warszawa, Poland
  • 02/2017: Ushering in the New Era of Microlensing from Space. 21st International Microlensing Conference, Pasadena, CA, USA
  • 09/2015: The Golden Age of Cataclysmic Variables and Related Objects - III, Palermo, Italy
  • 08/2015: iPTF Summer School, Pasadena, CA, USA


Cahill Center for Astronomy and Astrophysics
California Institute of Technology
1200 East California Blvd, MC 249-17
Pasadena, CA 91125
pmroz AT