Astronomer
I am a German-Swiss astronomer currently based at the Max Planck Institute for Radio Astronomy in Bonn, Germany.
Sebastiano D.
von Fellenberg, PhD
Research Interests
I am interested in the Galactic Center, the black hole it harbors and the stars surrounding it.
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Fascinated by the technology required and developed to study it.
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Contact me at:
sfellenberg at mpifr-bonn.mpg.de
I'm an active member of both the GRAVITY Collaboration, which studies the Sgr A* in the near infrared as well as member of the Event Horizon Telescope Collaboration (EHTC) which studies Sgr A* and other black holes at radio frequencies. I joined the EHTC in 2023.
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In both collaborations I am heavy involved in data calibration. I develope calibration strategies, both on a more conceptional level as well as on producing data products which can be used for interpretation.
I've contributed substainly to a novel method called dual-beam astrometry, which allows to track stars in the Galactic Center over large distances. This was instrumental in the detection of a so called Schwarzschild Precession of the star S2, a prediction of Einstein's General Relativity.
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In the EHT I've been leading efforts for the integration of the NOEMA into the VLBI array, which has joined observations for the first time in 2021. This will allow to get even sharper observations of the event horizon's of Sgr A* & M87. For this work, I have won the EHT Early Career Adward - twice.
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In January 2025, an international team of researchers and I published a paper on the first detection of a flare of Sgr A* in the Mid-Infrared using the James Webb Space Telescope. The paper was published in Astrophysical Journal Letters, and was first presented at 245th AAS Meeting in Maryland. Several press releases are available, including from my home institute. Some more details on these results are available here.
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Starting April 2025, I will start as an Alexander von Humboldt Feodor Lynen Fellow at the Canadian Institute for Theoretical Astrophysics (CITA) at the UofT in Toronto to work on observations and models of accretion flows like that of Sgr A*.
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Publications
S. D. von Fellenberg et al. 2022
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In this paper we studied the distribution of young stars in the Galactic Center. We found a new disk of young stars!
S.D. von Fellenberg et al. 2018
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A paper that reports on the first detection of Sgr A* at 160 and 100 micron!
Publications with important contributions
GRAVITY Collaboration et al. 2022
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In this work led by the MPE Galactic Center Team, I contributed the 2021 astrometry of stars zipping by the black hole.
Y. Dalillar et al. 2022
"Flaremodel: An open-source Python package for one-zone numerical modelling of synchrotron sources"
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I intiated this project led by Yigit Dalillar, and contributed to the code.
Non-Galactic Center Publications
von Fellenberg et al. 2023
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This paper discusses a peculiar 7-year precession in the radio jet of M81*, the second closest AGN to us! While temporal baseline of observations is to short to know for sure this could be explained by the presence of dynamical pace-maker: a IMBH companion.
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S.D. von Fellenberg et al. 2023
"General relativistic effects and the near-infrared and X-ray variability of Sgr A* I"
GRAVITY Collaboration et al. 2021
GRAVITY Collaboration et al. 2021
GRAVITY Collaboration et al. 2019
"A geometric distance measurement to the Galactic center black hole with 0.3% uncertainty"
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In this work led by the MPE Galactic Center Team, Felix Widman and I helped re-reduce all SINFONI spectroscopic observations. This led to a 46% improvement of the radial velocities.
