Seminars / Webinars
Tuesday 16 July 2024, 12:00 (EET)
Buckling instability in galactic bars
Ewa L. Lokas
Nicolaus Copernicus Astronomical Center, Warsaw
Abstract:
Many simulated galactic bars experience a period of buckling when their bar is distorted vertically out of the disk plane. The nature of buckling instability remains unclear and it is still debated if it results from trapping x1 orbits of the bar at vertical resonances or is rather related to the fire-hose instability and controlled by the ratio of the vertical to horizontal velocity dispersion of the stars in the bar. I will describe the results of the studies of the buckling instability performed with controlled N-body/hydro simulations of a bar forming in an isolated Milky Way-like galaxy. The properties of the bar at the time of buckling are quantified in terms of the mean acceleration, velocity and distortion in the vertical direction. The maps of these quantities in face-on projections reveal characteristic quadrupole patterns which wind up over a short timescale. From the study of the orbital structure of the bar in periods before and after buckling I find that most of the buckling orbits originate from x1 orbits supporting the bar. During buckling the ratio of the vertical to horizontal frequency of stellar orbits decreases dramatically and after buckling the orbits obey a very tight relation between the vertical and circular frequency. I propose that buckling is initiated by the vertical resonance of the x1 orbits creating the initial distortion of the bar that later evolves as kinematic bending waves. I will also discuss the effect of the gas component on buckling and the buckling phenomenon in tidally induced bars
Past webinar recordings are available here
Past Webinars
| Date | Speaker | Title |
| 25 June 2024 | Ewa L. Lokas Nicolaus Copernicus Astronomical Center, Warsaw |
Βuckling instability in galactic bars |
| 25 June 2024 | Georgios Loukes-Gerakopoulos Astronomical Institute, Czech Academy of Sciences |
The center of mass issue of an extended body moving in a curved spacetime |
| 25 June 2024 | Diego Valencia-Enríquez Universidad Mariana, Colombia |
Orbital Dynamics and Structural Evolution in Barred and Unbarred Disc Galaxy Models |
| 18 June 2024 | Francesca Fragkoudi Institute for Computational Cosmology, Department of Physics, Durham Universitu |
Barred galaxies in ΛCDM: Uncovering the formation history and dark matter content of Milky Way-type galaxies |
| 4 June 2024 | Athanasios C. Tzemos RCAAM of the Academy of Athens |
Advances in Bohmian Chaos |
| 28 April 2024 | Iannis Dandouras Institut de Recherche en Astrophysique et Planétologie CNRS / Université de Toulouse / CNES, Toulouse, France |
Space plasma physics from Moon orbit and from the Moon surface: opportunities provided by the Lunar Gateway programme |
| 24 April 2024 | Eugene Vasiliev Institute of Astronomy, University of Cambridge, UK |
Dynamical modelling of barred galaxies |
| 9 April 2024 | Francesco Sylos Labini Enrico Fermi Research Center, Rome, Italy |
Rotation curves of the Milky Way and of external galaxies and a new mass model |
12 March 2024 |
Fransisco Gonzalez Montoya UNAM and University of Leeds |
Normally Hyperbolic Invariant Manifolds in the Stormer problem: A generalization of the Unstable Periodic Orbits and its role in the transport in phase space |
| 6 February 2024 | Matheus M. A. Paixão Brazilian Center for Research in Physics |
Bohmian Mechanics, chaos, and the Unruh effect |
| 30 January 2024 | Henrique Santos Lima Brazilian Center for Research in Physics |
First-principle validation of Fourier’s law: a brief study of classical inertial n-vector models |
| 16 January 2024 | Janusz Mlynarczyk AGH University, Krakow, Poland |
Extremely low frequency electromagnetic waves in the Earth-ionosphere waveguide |
| 16 January 2024 | A. Burkert Chair of Theoretical and Computational Astrophysics Ludwig Maximilians University, Munich |
The turbulent dynamics of high-redshift disk galaxies |
| 9 January 2024 | A. Nathanail RCAAM of the Academy of Athens |
Short Gamma-ray bursts as binary neutron star mergers, or not? |
| 19 December 2023 | I. Contopoulos RCAAM of the Academy of Athens |
Τεχνητή Γενική Νοημοσύνη: Προκλήσεις και Ευκαιρίες |
| 12 December 2023 | G. Korkidis University of Crete |
A new probe of Cosmology |
| 28 November 2023 | Johan H. Knapen IAC Tenerife, Spain |
Uncovering galaxy history through deep imaging and machine learning |
| 21 November 2023 | Sophia Stuber Max-Planck-Institut für Astronomie, Heidelberg, Germany |
Molecular Gas Morphologies in Nearby Main Sequence Galaxies from PHANGS |
| 7 November 2023 | Jairo Méndez Abreu Universidad de La Laguna/Instituto de Astrofísica de Canarias |
The barred galaxy population in the distant Universe |
| 31 October 2023 | M. Bureau University of Oxford, UK |
Probing the Invisible: Weighing Supermassive Black Holes with ALMA |
| 24 October 2023 | S. Hozumi Shiga University, Otsu, Japan |
The origin of the bar properties generated by the bar instability in flat stellar disks |
| 11 July 2023 | M. Opher Astronomy Department, Boston University, Boston, MA, United States |
The Heliosphere, a case of a Habitable Astrosphere |
| 29 June 2023 | H. Skokos University of Cape Town, S. Africa |
Numerical approaches for investigating the chaotic behavior of multidimensional Hamiltonian systems |
| 20 June 2023 | D. Christodoulou University of Massachussets |
A Compendium of Research Projects from the Past Year |
| 23 May 2023 | K. Founta University of Thessaly |
Modelling and simulating a combat: Battle of Salamis |
| 16 May 2023 | K. Dialynas Center of Space Research & Technology, Academy of Athens |
The science of large scale heliosphere and missions that made it possible |
| 9 May 2023 | M. Sormani Universität Heidelberg |
The Galactic centre: structure, dynamics and star formation |
| 4 Apr 2023 | E. Floratos Academy of Athens |
Arnol'd cat map lattices |
28 Mar 2023 |
P. Erwin Max-Planck-Institute for Extraterrestrial Physics |
Composite Bulges: A Partial Zoology of Beasts that Live at Centers of Galaxy Disks |
| 9 Mar 2023 | M. Romero-Gomez |
Dynamics with Gaia in the Maggelanic Clouds |
| 31 Jan 2023 | Athanasios C. Tzemos |
Ergodicity and Born's rule in multiqubit Bohmian systems |
| 10 Jan 2023 | Tassos Bountis |
Long range interactions enhance stability in 1-D Hamiltonian lattices |
18 Oct 2022 |
Thomas Kotoulas |
Two-parametric families of orbits created by three-dimensional galactic-type potentials |
| 14 Oct 2022 | George Contopoulos |
(Spirals and bars in galaxies: One-day workshop) The spiral arms of galaxies (29:51) |
| 14 Oct 2022 | Kanak Saha |
(Spirals and bars in galaxies: One-day workshop) Revisiting spiral structures in galaxies (1:21:30) |
| 14 Oct 2022 | Lia Athanassoula |
(Spirals and bars in galaxies: One-day workshop) Understanding the Formation and Evolution of Bars using Simulations (2:24:23) |
| 14 Oct 2022 | Christos Efthymiopoulos |
(Spirals and bars in galaxies: One-day workshop) Manifolds and spirals under multiple pattern speeds (3:41:07) |
| 14 Oct 2022 | P. Grosbol European Southern Observatory (ESO), Munich, Germany |
(Spirals and bars in galaxies: One-day workshop) Interaction between spirals and bars in disk galaxies (4:33) |
| 14 Oct 2022 | M. Harsoula Research Center for Astronomy and Applied Mathematics, Academy of Athens |
(Spirals and bars in galaxies: One-day workshop) The building blocks of the spiral arms in galaxies (1:00:15) |
| 14 Oct 2022 | T. Naab Max-Planck Institut fuer Astrophysik, (MPA), Munich, Germany |
(Spirals and bars in galaxies: One-day workshop) The formation of galactic star cluster populations (1:45:06) |
| 14 Oct 2022 | P.A. Patsis Research Center for Astronomy and Applied Mathematics, Academy of Athens |
(Spirals and bars in galaxies: One-day workshop) Open questions about the association of observed structures and orbits in galactic disks (2:21:15) |
| 8 Sep 2022 | Malcolm Hillebrand Department of Mathematics and Applied Mathematics University of Cape Town |
Biophysical chaos: Bubbles in DNA molecules |
| 20 Jul 2022 | Suraj Dhiwar Prime Minister's Research Scholar, Department of Physics, IIT Guwahati, India |
Star Formation Quenching in L* Ellipticals | 18 Jul 2022 | Samik Mitra Prime Minister's Research Scholar, Department of Physics, IIT Guwahati, India |
Properties of general relativistic magneto-hydrodynamics accretion flows around black holes in steady-state limit (Watch here) |
| 12 Jul 2022 | Christos Efthymiopoulos University of Padova, Department of Mathematics |
The information approach to the interpretation of quantum mechanics (Watch here) |
| 5 Jul 2022 | Kanak Saha Inter-University Centre for Astronomy and Astrophysics, Pune, India |
Growth and survival of bars in disk galaxies (Watch here) |
| 28 Jun 2022 | Georgios Loukes-Gerakopoulos Astronomical Institute of the CAS, Czech Republic |
Celestial Mechanics of Extreme Mass Ratio Inspirals (Watch here) |
| 14 Jun 2022 | Matthaios Katsanikas Research Center for Astronomy and Applied Mathematics, Academy of Athens |
Stickiness in 3D rotating galactic potentials (Watch here) |
| 9 Jun 2022 | Makrina Agaoglou Instituto de Ciencias Matematicas, Madrid, Spain |
Transport processes on a Potential Energy Surface with four wells, four index-1 saddles and an index-2 saddle (Watch here) |
| 24 May 2022 | Susanna Parenti Institut d'Astrophysique Spatiale, France |
Validation of a wave heated 3D MHD coronal-wind model using Polarized Brightness and EUV observations (Watch here) |
| 17 May 2022 | Konstantina Zouloumi Research Center for Astronomy & Applied Mathematics & Department of Astrophysics, Astronomy and Mechanics, University of Athens |
NAAF determination of the multiple pattern speeds and the manifolds in a simulation of a barred spiral galaxy (Watch here) |
| 3 May 2022 | Antonios Tsokaros University of Illinois at Urbana-Champaign, USA |
Numerical general relativity and astrophysics in the era of multimessenger astronomy (Watch here) |
| 18 Apr 2022 | Stavros Pastras Research Center for Astronomy and Applied Mathematics, Academy of Athens & Department of Physics, Section of Astrophysics, Astronomy and Mechanics, University of Athens |
Gasflows in barred spiral galaxies by means of two different hydrocodes (Watch here) |
| 12 Apr 2022 | Spyridon Aleiferis UK Atomic Energy Authority, Culham Science Centre, Abingdon, UK |
Taming of the stars: how to control fusion plasmas (Watch here) |
| 31 Mar 2022 | Evangelos Melas University of Athens, Department of Economics |
Asymptotic symmetries and representation theory in General Relativity in three and four space-time dimensions (Watch here) |
| 29 Mar 2022 | Georgios Doulis Institute of Theoretical Physics, University of Jena, Germany |
Entropy as shock indicator in neutron star merger simulations (Watch here) |
| 15 Mar 2022 | Dimitris Stamatellos Jeremiah Horrocks Institute for Mathematics, Physics & Astronomy, University of Central Lancashire, Preston, UK |
The formation and evolution of disc-instability planets (Watch here) |
| 10 Mar 2022 | Damianos Iosifidis Aristotle University of Thessaloniki |
Perfect Hyperfluids (Watch here) |
| 8 Mar 2022 | Antonios Nathanail University of Athens, Department of Physics |
Still observing light from the binary neutron star merger first detected in 2017 (Watch here) |
| 3 Mar 2022 | Karnesis Nikolaos Aristotle University of Thessaloniki, School of Physics |
Detecting Gravitational Waves from space (Watch here) |
| 22 Feb 2022 | Athanasios C. Tzemos Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Chaos and Bohmian Quantum Potential (Watch here) |
| 15 Feb 2022 | Ioannis Contopoulos Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Quantum Interference: reality or an illusion of the detector? (Watch here) |
| 8 Feb 2022 | Charis Anastopoulos Department of Physics, University of Patras |
Gravitational effects in macroscopic quantum systems (Watch here) |
| 1 Feb 2022 | Konstantinos N. Gourgouliatos Department of Physics, University of Patras |
Magnetic Field Evolution in Neutron Star Crusts: Hall effect and beyond ( Watch here) |
| 18 Jan 2022 | Athanasios C. Tzemos Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Born's rule in the case of 3 entangled Bohmian qubits (Watch here) |
| 11 Jan 2022 | Constantinos Kalapotharakos University of Maryland and Astrophysics Science Division, NASA/Goddard Space Flight Center, USA |
Interpreting the Thermal and Non-Thermal High-Energy Emission in Multipolar Field Pulsar Magnetospheres (Watch here) |
| 14 Dec 2021 | Thorsten Naab Max-Planck-Institute for Astrophysics, Garching, Germany |
The GRIFFIN project - towards realistic simulations of galactic star cluster populations (Watch here) |
| 7 Dec 2021 | Ivan Minchev Leibniz-Institut für Astrophysik Potsdam (AIP) |
Modeling the Galactic disk in the age of Gaia (Watch here) |
| 30 Nov 2021 | Edoardo Legnaro Research Center for Astronomy and Applied Mathematics of the Academy of Athens and University of Thessaloniki |
Analytic Theory for Secular Lunisolar Resonances (Watch here) |
| 9 Nov 2021 | Dimitri A. Gadotti ESO – European Southern Observatory |
Nuclear discs in external galaxies and the Milky Way: building "bulges" without mergers (Watch here) |
| 26 Oct 2021 | Demosthenes Kazanas NASA Goddard Space Flight Center, Corresponding Member of the Academy of Athens |
Gravity beyond Einstein? Yes, but in which direction? (Watch here) |
| 13 Jul 2021 | Dimitris Christodoulou University of Massachusetts |
Major-Body Clustering in the Solar System (Watch here) |
| 24 Jun 2021 | Panos A. Patsis Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Building blocks of 3D, X-shaped bulges and thick spirals (Watch here) |
| 8 Jun 2021 | George Contopoulos Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Μια συνοπτική έκθεση της Φιλοσοφίας της Φυσικής και των Μαθηματικών (Διαθέσιμη μαγνητοσκοπημένη) |
| 1 Jun 2021 | Christos Efthymiopoulos Department of Mathematics Tullio Levi-Civita, University of Padua (Work in collaboration with Rita Mastroianni) |
Secular dynamics for exoplanetary systems with two planets in mutually inclined orbits (Watch here) |
| 13 May 2021 | Athanasios C. Tzemos Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Born's Rule in the case of two entangled Bohmian qubits
(Watch here) |
| 22 Apr 2021 | Costis Gontikakis Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Study of the emission measure during a solar flare observed with IRIS spectrograph (Watch here) |
Seminars in 2020
| Date | Speaker | Title |
| 3 Mar 2020 | Anastasios Anastasiadis National Observatory of Athens / IAASARS |
Unveiling Current Challenges in Space Weather Forecasting: The SAWS-ASPECS tool |
| 25 Feb 2020 | Vasileios Basios Université Libre de Bruxelles, Interdisciplinary Centre for Nonlinear Phenomena & Complex Systems (Cenoli-ULB) & Département de Physique des Systèmes Complexes et Mécanique Statistique |
Labyrinth Chaos: Conservative, non-Hamiltonian Chaos without Attractors |
| 18 Feb 2020 | Elias Koulouridis National Observatory of Athens / IAASARS |
Tracing the Universe: X-ray surveys and cosmology |
| 11 Feb 2020 | Costis Gontikakis Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Moss, the trace of hot loops in EUV, an ongoing research |
| 28 Jan 2020 | Athanassios C. Tzemos Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Chaos and ergodicity in the trajectories of two entangled Bohmian qubits |
| 21 Jan 2020 | George Dimopoulos National Observatory of Athens |
Coronal properties of Sy I Active Galaxies |
| 14 Jan 2020 | Panos A. Patsis Research Center for Astronomy and Applied Mathematics of the Academy of Athens |
Some open issues in Galactic Dynamics and the contribution of Image Processing in resolving them |
A list of all previous seminars from 2008 to 2020 is available here.
