About Me
I am a Marie Curie Fellow at the University of Vienna in the Department of Astrophysics, working on star clusters.
My project is Old anD Young Star clusterS tracing Evolution and assemblY (ODYSSEY).
Previously, I was a Research Fellow at the European Space Agency and a PhD student at the European Southern Observatory.
Research
I am interested in star clusters, in particular nuclear star clusters and globular clusters. Both nuclear star clusters and globular clsuters are massive, dense star clusters that contain millions of stars tightly packed into a few parsecs, making them the densest stellar objects in the Universe. Globular clusters are found in basically all galaxies, from low mass dwarfs, over our own Milky Way to the most massive galaxies, but also nuclear star clusters are very common: around 70% of galaxies contain a NSC in their centre.
I am particularly interested in the question how nuclear star clusters form. Generally, there are two proposed mechanisms: either nuclear star clusters form from eating up GCs that fall into the galaxy centre as a result of dynamical friction - directly connecting GCs and nuclear star clusters - or nuclear star clusters might form independently from the GCs from gas that fell into the centre. But the connection between GCs and nuclear star clusters might also work in the other direction: so-called ultra compact dwarf galaxies (UCDs) share the high stellar densities and sizes of nuclear star clusters and were proposed to be either the high-mass end of the GC population or remnant nuclear star clusters that were stripped from their host galaxy in a merger. Therefore, a GC population might also be hiding some stripped nuclear star clusters - as it has been proposed for Omega Centauri, the most massive GC in our MW.
Nuclear star cluster formation scenarios. Left: Globular cluster accretion scenario where a nuclear star cluster forms out of globular clusters that spiral into the center of a galaxy due to dynamical friction. Right: In-situ formation scenario. Here, the nuclear star cluster forms directly at the center out of gas that is undergoing star formation.
To study nuclear star clusters and globular clusters, I use integral-field spectroscopy data from the Multi Unit Spectrscopic Explorer (MUSE), mounted at ESO's Very Large Telescope. MUSE is a great instrument because it combines imaging with spectroscopy - allowing us to study the spectra of individual star clusters alongside with the underlying host galaxy. By fitting the spectra with models, we can then infer the kinematic and chemical properties of these star clusters and how those compare to the galaxies they live in. The figure below shows nine late-type (gas-rich) dwarf galaxies that I recently analysed. The nuclear star clusters are highlighted in the zoom-ins.
Sample of nucleated late-type (gas-rich) dwarf galaxies.
MSCA ODYSSEY
My Marie Curie fellowship project at the University of Vienna is called "Old anD Young Star clusterS tracing Evolution and assemblY (ODYSSEY)". It is funded through the European Union's Horizon Europe programme.
In ODYSSEY, I will study massive star clusters such as globular clusters, nuclear star clusters and young massive clusters in different galactic environments, using observational data from various telescopes and instruments.
Publications
A list of my publications can be found at the ADS or check my ORCID page.
"Growing a nuclear star cluster from star formation and cluster mergers: The JWST NIRSpec view of NGC 4654"
K. Fahrion, T. Böker, M. Perna, T. L. Beck, R. Maiolino, S. Arribas, A. J. Bunker, S. Charlot, M. Ceci, G. Cresci, G. De Marchi, N. Lützgendorf
L. Ulivi
2024, A&A, 687, 83
"The hierarchical formation of 30 Doradus as seen by JWST"
K. Fahrion & G. De Marchi
2024, A&A, 681, 20
"Extending the extinction law in 30 Doradus to the infrared with JWST"
K. Fahrion & G. De Marchi
2023, A&A, 671, 14
"Nuclear star cluster formation in star-forming dwarf galaxies"
K. Fahrion, T.-E. Bulichi, M. Hilker, R. Leaman, M. Lyubenova, O. Müller, N. Neumayer, F. Pinna, M. Rejkuba, G. van de Ven
2022, A&A, 667, 101
"Evaluating the feasibility of interpretable machine learning for globular cluster detection"
D. Dold & K. Fahrion
2022, A&A, 663, A81, A81.
"Disentangling the formation mechanisms of nuclear star clusters"
K. Fahrion, R. Leaman, M. Lyubenova, G. van de Ven
2022, A&A, 658, 172
"Diversity of nuclear star cluster formation mechanisms revealed by their star formation histories"
K. Fahrion, M. Lyubenova, G. van de Ven, M. Hilker, R. Leaman, J. Falcón-Barroso, A. Bittner, L. Coccato, E. M. Corsini, D. A. Gadotti, E. Iodice, R. M. McDermid, I. Martín-Navarro, F. Pinna, A. Poci, M. Sarzi, P. T. de Zeeuw, L. Zhu
2021, A&A, 650, 137
"The Fornax 3D project: Non-linear colour-metallicity relation of globular clusters"
K. Fahrion, M. Lyubenova, M. Hilker, G. van de Ven, J. Falcón-Barroso, R. Leaman, I. Martín-Navarro, A. Bittner, L. Coccato, E. M. Corsini, D. A. Gadotti, E. Iodice, R. M. McDermid, F. Pinna, M. Sarzi, S. Viaene, P. T. de Zeeuw, L. Zhu
2020, A&A, 637, A27
"The Fornax 3D project: Globular clusters tracing kinematics and metallicities"
K. Fahrion, M. Lyubenova, M. Hilker, G. van de Ven, J. Falcón-Barroso, R. Leaman, I. Martín-Navarro, A. Bittner, L. Coccato, E. M. Corsini, D. A. Gadotti, E. Iodice, R. M. McDermid, F. Pinna, M. Sarzi, S. Viaene, P. T. de Zeeuw, L. Zhu
2020, A&A, 637, A26
"Metal-poor nuclear star clusters in two dwarf galaxies near Centaurus A suggesting formation from the in-spiraling of globular clusters"
K. Fahrion, O. Müller, M. Rejkuba, M. Hilker, M. Lyubenova, G. van de Ven, I. Georgiev, F. Lelli, M. S. Pawlowski, H. Jerjen
2020, A&A, 634, A53
"Constraining nuclear star cluster formation using MUSE-AO observations of the early-type galaxy FCC47"
K. Fahrion, M. Lyubenova, G. van de Ven, R. Leaman, M. Hilker, I. Martin-Navarro, L. Zhu, M. Alfaro-Cuello, L. Coccato, E. M. Corsini,
J. Falcon-Barroso, E. Iodice, R. M. McDermid, M. Sarzi, T. de Zeeuw
2019, A&A, 628, A92
"Single metal-poor ultra compact dwarf galaxy at one kiloparsec distance from the low-mass elliptical galaxy FCC47"
K. Fahrion, I. Georgiev, M. Hilker, M. Lyubenova, G. van de Ven, M. Alfaro-Cuello, E. M. Corsini, M. Sarzi, R. M. McDermid, T. de Zeeuw
2019, A&A, 625, A50
"Disentangling the ISM phases of the dwarf galaxy NGC 4214 using [C II] SOFIA/GREAT observations"
K. Fahrion, D. Cormier, F. Bigiel, S. Hony, N. P. Abel, P. Cigan, T. Csengeri, U. U. Graf, V. Lebouteiller, S. C. Madden, R. Wu, L. Young
2017, A&A, 599, A9
"Young Stellar Objects in NGC 346: A JWST NIRCam/MIRI Imaging Survey"
N. Habel, C. Nally, L. Lenkic, M. Meixner, G. de Marchi, P. J. Kavanagh, K. Fahrion, O. Nayak, A. S. Hirschauer,
O. Jones, K. Biazzo, B. R. Brandl, J. Jaspers, K. Pontoppidan, R. Massimo, C. Rogers, E. Sabbi, B. A. Sargent, D. R. Soderblom, P. Zeidler
arXiv:2404.16242
"No evidence of AGN features in the nuclei of Arp 220 from JWST/NIRSpec IFS"
M. Perna, S. Arribas, I. Lamperti, M. Pereira-Santaella, L. Ulivi, T. Böker, R. Maiolino, A. J. Bunker, S. Charlot, G. Cresci,
B. Rodriguez Del Pino, F. D'Eugenio, H. Übler, K. Fahrion, M. Ceci
2024, MNRAS, 527, 5767
"Measuring distances to galaxies with globular cluster velocity dispersions"
M. Beasley, K. Fahrion, A. Gvozdenko
2024, MNRAS, 527, 5767
"Expanding on the fundamental metallicity relation in dwarf galaxies with MUSE"
T.-E. Bulichi, K. Fahrion, F. Mernier, M. Hilker, R. Leaman, M. Lyubenova, O. Müller, N. Neumayer, I. Martin-Navarro, F. Pinna M. Rejkuba, G. van de Ven
2023, A&A, 679, 98
"Looking into the faintEst WIth MUSE (LEWIS): Exploring the nature of ultra-diffuse galaxies in the Hydra-I cluster. I. Project description and preliminary results"
E. Iodice, M. Hilker, G. Doll, M. Mirabile, C. Buttitta, J. Hartke, S. Mieske, M. Cantiello, G. D'Ago, D. Forbes, M. Gullieuszik, M. Rejkuba, M. Spavone, C. Spiniello, M. Arnaboldi,
E. M. Corsini, L. Greggio, J. Falcón-Barroso, K. Fahrion, J. Fritz, A. La Marca, M. Paolillo, A. M. Raj, R. Rampazzo, M. Sarzi, G. Capasso
2023, A&A, 679, 69
"Effect of the initial mass function on the dynamical SMBH mass estimate in the nucleated early-type galaxy FCC 47"
S. Thater, M. Lyubenova, K. Fahrion, I. Martín-Navarro, P. Jethwa, D. D. Nguyen, G. van de Ven,
arXiv:2304.13310, accepted in A&A
"The Fornax3D project: Environmental effects on the assembly of dynamically cold disks in Fornax cluster galaxies "
Y. Ding, L. Zhu, G. van de Ven, L. Coccato, E. M. Corsini, L. Constantin, K. Fahrion,
J. Falcon-Barroso, D. A. Gadotti, E. Iodice, M. Lyubenova, I. Martin-Navarro, F. Pinna, R. M. McDermid, M. Sarzi
2023, A&A, 672, 84
"JWST/NIRCam detections of dusty subsolar-mass young stellar objects in the Small Magellanic Cloud"
O. Jones, C. Nally, N. Habel, L. Lenkic, K. Fahrion, A. S. Hirschauer, L. E. U. Chu, M. Meixner, G. de Marchi, R. Massimo, E. Sabbi, P. Zeidler, O. Nayak, K. Pontoppidan,
K. Biazzo, G. Giardino, B. A. Sargent, D. R. Soderblom
2023, NatAs, 7, 694
"The survival of stellar discs in Fornax-like environments, from TNG50 to real galaxies "
P. M. Galán-de Anta, M. Sarzi, A. Pillepich, Y. Ding, L. Zhu, L. Coccato, E. M. Corsini, K. Fahrion,
J. Falcon-Barroso, D. A. Gadotti, E. Iodice, M. Lyubenova, I. Martin-Navarro, F. Pinna, G. van de Ven, P. T. de Zeeuw,
2022, MNRAS, 517, 5992
"A new method for age-dating the formation of bars in disc galaxies: The TIMER view on NGC1433's old bar and the inside-out growth of its nuclear disc"
C. de Sá-Freitas, F. Fragkoudi, Francesca, D. A. Gadotti, Dimitri A, J. Falcón-Barroso, A. Bittner, P. Sánchez-Blázquez, Patricia,
G. van de Ven, R. Bieri, L. Coccato, P. Coelho, K. Fahrion, G. Gonçalves, T. Kim, A. de Lorenzo-Cáceres, M. Martig, I. Martín-Navarro,
J. Mendez-Abreu, J. Neumann, M. Querejeta
2023, A&A, 671A, 8D
"Testing the robustness of DYNAMITE triaxial Schwarzschild modelling: The effects of correcting the orbit mirroring "
S. Thater, P. Jethwa, B. Tahmasebzadeh, L. Zhu, M. den Brok, G. Santucci, Y. Ding, A. Poci, E. Lilley, P. T. de Zeeuw, A. Zocchi, T. I. Maindl, F. Rigamonti, G. van de Ven, M. Yang and K. Fahrion
2022, A&A, 667, 51
"The Fornax3D Project: Intrinsic Correlations between orbital properties and the stellar Initial Mass Function"
A. Poci, R. M. McDermid, M. Lyubenova, I. Martin-Navarro, G. van de Ven, L. Coccato, E. M. Corsini, K. Fahrion,
J. Falcon-Barroso, D. A. Gadotti, E. Iodice, F. Pinna, M. Sarzi, P. T. de Zeeuw, L. Zhu
2022, MNRAS, 514, 3660
"The Fornax3D project: discovery of ancient massive merger events in the Fornax cluster galaxies NGC 1380 and NGC 1427"
L. Zhu, G. van de Ven, R. Leaman, A. Pillepich, L. Coccato, Ding Y., J. Falcón-Barroso, E. Iodice, I. Martín-Navarro, F. Pinna, E. M. Corsini, D. A. Gadotti, K. Fahrion,
M. Lyubenova, S. Mao, R. McDermid, A. Poci, M. Sarzi, P. T., de Zeeuw
2022, A&A, 664, A115
"The Fornax3D project: The assembly history of massive early-type galaxies in the Fornax cluster from deep imaging and integral field spectroscopy"
M. Spavone, E. Iodice, G. D'Ago, A. Poci, G. van de Ven, L. Morelli, E. M. Corsini, M. Sarzi, L. Coccato, K. Fahrion,
J. Falcon-Barroso, D. A. Gadotti, M. Lyubenova, I. Martin-Navarro, R. M. McDermid, F. Pinna, A. Pizzella, A. Poci, P. T. de Zeeuw, L. Zhu
2022, A&A, 663, A135
"The Fornax3D project: The environmental impact on gas metallicity gradients in Fornax cluster galaxies"
M. A. Lara-Lopez, P. M. Galan-de Anta, M. Sarzi, E. Iodice, T. A. Davis, N. Zabel, E. M. Corsini, P. T. de Zeeuw,
K. Fahrion, J. Falcón-Barroso, D. A. Gadotti, R. M. McDermid, F. Pinna, V. Rodriguez-Gomez,
G. van de Ven, L. Zhu, L. Coccato, M. Lyubenova, I. Martín-Navarro
2022, A&A, 660, A105
"The Cen A galaxy group: dynamical mass and missing baryons "
O. Müller, F. Lelli, B. Famaey, M. S. Pawlowski,K. Fahrion, M. Rejkuba, M. Hilker and H. Jerjen
2022, A&A, 662, A57
"The Fornax Cluster VLT Spectroscopic Survey III -- Kinematical characterisation of globular clusters across the Fornax galaxy cluster"
A. Chaturvedi, M. Hilker, M. Cantiello, N. R. Napolitano, G. van de Ven, C. Spiniello,
K. Fahrion,M. Paolillo, M. Gatto, T. Puzia
2022, A&A, 657, A93
"Fornax 3D project: assessing the diversity of IMF and stellar population maps within the Fornax Cluster"
I. Martín-Navarro, F. Pinna, L. Coccato, J. Falcón-Barroso, G. van de Ven, M. Lyubenova, E. M. Corsini, K. Fahrion,
D. A. Gadotti, E. Iodice, R. M. McDermid, A. Poci, M. Sarzi, T. W. Spriggs, S. Viaene,
P. T. de Zeeuw, L. Zhu
2021, A&A, 654, A59
"The Fornax3D project: PNe populations and stellar metallicity in edge-on galaxies"
P. M. Galán-de Anta, M. Sarzi, T. W. Spriggs, B. Nedelchev, F. Pinna, I. Martín-Navarro, L. Coccato, E. M. Corsini, P. T. de Zeeuw, J. Falcón-Barroso,
D. A. Gadotti, E. Iodice, R. J. J. Grand, K. Fahrion, M. Lyubenova, R. M. McDermid, L. Morelli, G. van de Ven, G., S. Viaene, L. Zhu
2021, A&A, 652, A109
"The Fornax3D project: the Assembly Histories of Lenticular Galaxies from a Combined Dynamics and Population Orbital Analysis"
A. Poci, R. M. McDermid, M. Lyubenova, L. Zhu, G. van de Ven, E. Iodice, L. Coccato, E. M. Corsini, J.Falcón-Barroso, D. A. Gadotti, K. Fahrion, I. Martı́n-Navarro, F. Pinna, M. Sarzi, S. Viaene and P. T. de Zeeuw
2021, A&A, 647, A145
"The coherent motion of Cen A dwarf satellite galaxies remains a challenge for ΛCDM cosmology "
O. Müller, M. S. Pawlowski, F. Lelli, K. Fahrion, M. Rejkuba, M. Hilker, J. Kanehisa, N. Libeskind and H. Jerjen
2021, A&A, 645, A5
"The properties of dwarf spheroidal galaxies in the Cen A group: - Stellar populations, internal dynamics, and a heart-shaped Halpha ring"
O. Müller, K. Fahrion, M. Rejkuba, M. Hilker, F. Lelli, K. Lutz, M. S. Pawlowski, L. Coccato, G. S. Anand and H. Jerjen
2021, A&A, 645, A92
"Globular cluster ejection, infall, and the host dark matter halo of the Pegasus dwarf galaxy "
R. Leaman, T. Ruiz-Lara, A. A. Cole, M. Beasley, A. Boecker, K. Fahrion, P. Bianchini, J. Falcón-Barroso, J. Webb, A. Sills, A. Mastrobuono-Battisti, N. Neumayer, Nadine; A. C. Sippel,
2020, MNRAS, 492, 5102L
"Fornax3D project: Overall goals, galaxy sample, MUSE data analysis, and initial results"
M. Sarzi, E. Iodice, L. Coccato, E. M. Corsini, T. de Zeeuw, J. Falcón-Barroso, D. A. Gadotti, M. Lyubenova, R. M. McDermid, G. van de Ven, K. Fahrion, A. Pizzella, L. Zhu
2018, A&A, 616, A121
"Using MUSE-AO observations to constrain the formation of the large nuclear star cluster in FCC47 "
K. Fahrion, M. Lyubenova, G. van de Ven, M. Hilker
2020, IAUS, 351, 108F , Proceedings of the IAU symposium 351
Curriculum Vitae
Research positions
Since 09/2024:
Marie Curie Fellow
University of Vienna, Department of Astrophysics
10/2021 - 08/2024:
Internal Research Fellow
European Space Agency, Noordwijk, the Netherlands
09/2018 - 08/2021:
PhD Research Fellow
European Southern Observatory, Garching, Germany
Education
09/2018 - 08/2021:
PhD in Astronomy , graduated summa cum laude
Thesis: "The Build-up of Galactic Stellar Nuclei" ( available here. ) conducted at
European Southern Observatory, Garching, Germany
Ludwig-Maximilians University Munich, Germany
Supervisor: Dr. Maryia Lyubenova
04/2016 - 07/2018:
Master of Science in Physics
Ruprecht-Karls-Universität Heidelberg, Germany
Thesis: "Globular Cluster Systems and the Connection to Nuclear Star Cluster Formation"
10/2012 - 04/2016:
Bachelor of Science in Physics
Ruprecht-Karls-Universität Heidelberg, Germany
Thesis: "Deciphering Star Formation at low Metallicity - New SOFIA Observations of the Dwarf Galaxy NGC4214"
Invited Talks
10/2023:
"Nuclear star cluster formation in the context of galaxy evolution"
Joint UniGE-EPFL Astronomy Colloquium, Geneva, Switzerland.
10/2023:
"Nuclear star cluster formation in dwarf and massive galaxies"
Helsinki Astrophysics Seminar, Helsinki, Finland.
07/2023:
"Nuclear star cluster formation in the context of galaxy evolution"
EAS Annual Meeting 2023, Session SS28 "Understanding the connection between nuclear star clusters, black holes and galaxy evolution",
Krakow, Poland.
07/2023:
"IMBH formation in nuclear star clusters"
EAS Annual Meeting 2023, Symposium S12 "Breaking down the AGN frontiers: light and sound from early black holes",
Krakow, Poland.
10/2022:
"How do nuclear star clusters form in different galaxies?"
KT Boost Workshop, AIP Potsdam, Germany.
02/2022:
"Deciphering the formation of nuclear star clusters"
DAO Herzberg Astronomy Colloquium, National Research Council of Canada.
01/2022:
"The Formation of Nuclear Star Clusters"
Radboud Astrophysics Colloquium, Radboud University Nijmegen.
12/2021:
"The Formation of Nuclear Star Clusters"
CfA Seminar, Center for Astrophysics, Harvard \& Smithsonian.
03/2021:
"How do nuclear star clusters form?"
Chalmers Astrophysics Colloquium, Chalmers, Goteborg
Recent Conference Talks
10/2023:
"Unveiling nuclear star cluster formation with stellar population analysis"
A life devoted to stellar populations, Puerto de la Cruz, Tenerife, Spain.
08/2023:
"Nuclear star cluster formation in the context of galaxy evolution and star cluster systems"
MODEST-23, Evanston, IL, USA.
07/2023:
"Globular cluster systems with MUSE: How good are globular clusters as tracers of galaxy properties?"
EAS Annual Meeting 2023, Session SS10 "The edge of galaxies from field to cluster environment: the build-p of stellar haloes",
Krakow, Poland.
09/2022:
"Nuclear star cluster formation in dwarf galaxies"
Origin, growth and feedback of black holes in dwarf galaxies, San Sebastian, Spain.
03/2022:
"Globular cluster systems viewed with MUSE as tracers of galaxy assembly"
Aspen Winter Conference: Globular Clusters.
06/2021:
"Globular clusters as tracers of galaxy properties and assembly"
EAS 2021, SS10 "Extragalactic Globular Clusters with upcoming wide-field space-based surveys".
04/2021:
"Globular clusters as tracers of galaxy properties"
Galspec 2021 Conference
Skills
Languages:
German: native
English: fluent
French: beginner
Programming: experienced with python, beginner in IDL & C++
Data analysis: imfit, pPXF, iraf
Technical skills: LaTex, MS Office, Inkscape, Gimp
Basic data reduction with MUSE, ERIS, SINFONI esoreflex pipeline + ZAP, JWST NIRCam
Observational experience: with the Atacama Pathfinder EXperiment (APEX) submilimeter telescope (two week observing shift)
Teaching & Outreach
Nature News & Views article "Ultra-compact oddities are galaxies stripped of stars"
Faszination Astronomie Online: Sternhaufen - Fossilien der Galaxienentwicklung
ESO blog: Astronomer on tour - The story of a trip to Chile to observe with the APEX telescope
09/2018 - present: Tour guide at ESO supernova
2017: Teaching assistent "Introduction into Astronomy and Astrophysics II", University Heidelberg
2016: Teaching assistent "Introduction into Astronomy and Astrophysics I", University Heidelberg
2014: Teaching assistent "Beginner's Lab Course in Physics", University Heidelberg
Courses and Training
December 2023: Tools to challenge unacceptable behaviour - Active Bystander Training, training at ESA
November 2023: Overcoming hurdles in academia, training at ESA
January 2023: Managing upwards, training at ESA
November 2022: Mentoring training, ESA
November 2020: Physics of the Cosmic Microwave Background, IMPRS advanced course
October 2020: Stellar populations, IMPRS advanced course
March 2020: Galaxy formation, IMPRS advanced course
January 2020: Astrobiology, IMPRS advanced course
November 2019: Cosmic structure formation, IMPRS advanced course
April 2019: Third ASTERICS-OBELICS International School, advanced software programming for astrophysics and astroparticle physics
April 2019: Communication Skills Training at European Southern Observatory
February 2019: Astrophysics of black holes, IMPRS advanced course
January 2019: High resolution astrophysics, IMPRS advanced course
November 2018: Training Session: Avoiding and challenging harassment at European Southern Observatory