Relativistic outflow in the galaxy M87: The first hundred parsecs
Date of defence: 09 December 2024
Scientifi Advisor: A. P. Lobanov
Collaborators: A. J. Zensus, Y.Y Kovalev, T. Savolainen, M. Giroletti, J. Kim, H. Mueller, M. M. Lisakov, J. L. Livingston, E. V. Kravchenko, I. N. Pashchenko, V. A. Frolova, E. E. Nokhrina.
Total intensity image of M87 at 8 GHz observed by VLBA. Color shows logarithmic scale intensity. The image is overlaid by the Kelvin-Helmholtz instability (KHI) produced threads. Study show that KHI evolves from parsec scales up to the kiloparsecs as seen from the VLA observations analyzed by Lobanov et. al. 2003.
Total intensity image of M87 at 8 GHz observed by VLBA. Color shows logarithmic scale intensity. The image is overlaid by the Kelvin-Helmholtz instability (KHI) produced threads. Study show that KHI evolves from parsec scales up to the kiloparsecs as seen from the VLA observations analyzed by Lobanov et. al. 2003.
This project focuses on the study of relativistic jets from the active galactic nucleus (AGN) of the galaxy M87, a key example of supermassive black hole-powered jets. These highly collimated plasma streams, accelerated to nearly the speed of light, play a critical role in galaxy evolution and serve as natural laboratories for testing fundamental physical theories.
Total intensity image of the jet in M 87 at 8 GHz (colour) restored with an elliptical beam of 8 × 3 mas, PA = 0◦ approximately equivalent to the restoring beam of a VLBA observation of M 87 at 18 cm. The peak flux density in the image is 1.7 Jy/beam. The HST-1 feature is located at ≈ 850 mas from the core. The insets show the contour image of the inner 450 mas of the jet at 15 GHz (bottom) and the HST-1 region at 8 GHz (top left) and 15 GHz (top right), with the lowest contour level at 156 μJy/beam and successive contour levels increasing by a factor of √2. The HST-1 feature has a peak flux density of 1.4 mJy/beam and 0.8 mJy/beam at 8 GHz and 15 GHz, respectively.
Total intensity image of the jet in M 87 at 8 GHz (colour) restored with an elliptical beam of 8 × 3 mas, PA = 0◦ approximately equivalent to the restoring beam of a VLBA observation of M 87 at 18 cm. The peak flux density in the image is 1.7 Jy/beam. The HST-1 feature is located at ≈ 850 mas from the core. The insets show the contour image of the inner 450 mas of the jet at 15 GHz (bottom) and the HST-1 region at 8 GHz (top left) and 15 GHz (top right), with the lowest contour level at 156 μJy/beam and successive contour levels increasing by a factor of √2. The HST-1 feature has a peak flux density of 1.4 mJy/beam and 0.8 mJy/beam at 8 GHz and 15 GHz, respectively.
The magnetic field strength profile in the HST-1 knot is represented by orange dots. The light-blue shading indicates the uncertainties. The data was binned using the median within each bin, with a bin size set to 1/5th of the beam. The median value over the HST-1 profile is B_HST-1 = 3 ± 2 mG.
The magnetic field strength profile in the HST-1 knot is represented by orange dots. The light-blue shading indicates the uncertainties. The data was binned using the median within each bin, with a bin size set to 1/5th of the beam. The median value over the HST-1 profile is B_HST-1 = 3 ± 2 mG.
Through high-resolution very long baseline interferometry (VLBI) imaging at multiple frequencies, the research reveals the intricate internal structure of M87's jet across linear scales from 0.01 to 100 parsecs. Key findings include the discovery of helical structures interpreted as Kelvin-Helmholtz instability (KHI) threads, evidence of a helical magnetic field, and insights into the spectral and polarization properties of the jet. The study also examines the enigmatic HST-1 feature, resolving its spectral and magnetic field characteristics and assessing its role in jet collimation.
The project further advances radio imaging techniques by applying a novel Bayesian reconstruction algorithm to improve imaging fidelity and mitigate biases in sparsely sampled interferometric data. This comprehensive investigation enhances our understanding of jet dynamics, stability, and magnetic fields, contributing valuable knowledge to the field of AGN jet physics.
About me:
From October 2021 to December 2024, I was a PhD student in the VLBI group at the Max Planck Institute for Radio Astronomy under the supervision of Dr. A. P. Lobanov and Prof. Dr. A. J. Zensus and a member of the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics. My research focused on studying the structure and dynamics of relativistic jets in the active galactic nucleus (AGN) of M87 using state-of-the-art very long baseline interferometry (VLBI) techniques. This work included investigating helical structures in the jet, analyzing spectral and polarization properties, and applying advanced image reconstruction methods to enhance the fidelity of VLBI observations.
My journey into astrophysics began in my hometown of Yakutsk, Republic of Sakha (Yakutia), Russian Federation—the coldest town on Earth. Fascinated by astronomy from an early age, I participated in national and international astronomy olympiads, where I first became captivated by quasars and other enigmatic cosmic phenomena. I pursued my passion at Lomonosov Moscow State University, earning a specialist degree under the supervision of Prof. Dr. Y. Y. Kovalev, where I began studying M87 using VLBI data.
Joining the VLBI department at MPIfR was a fantastic experience that not only advanced my scientific career but also introduced me to an inspiring academic community and lifelong collaborators.
