It is now observationally established that the Milky Way harbours a prominent stellar bar in the central region. However, despite several past studies, the properties of the Milky Way’s bar (e.g. strength, length, orientation with respect to the Sun, and pattern speed) have remained ill-constrained till date. The European Space Agency’s Gaia mission has provided an unprecedented, holistic view of the MW by measuring the 6-D position-velocity and chemistry of 33 million stars in the Solar Neighbourhood and beyond. Furthermore, the Third Gaia data release (Gaia DR3) has revealed a quadrupole or butterfly-like pattern in the stellar mean radial velocity field of the Milky Way. Past studies indicated that a stellar bar can excite such a quadrupole feature. However, a systematic study investigating the co-evolution of bar and quadrupole structure is largely missing. In this talk, using a suite of isolated N-body models forming prominent bars and a sample of Milky Way-like barred galaxies from the TNG50 cosmological simulation, I will discuss the how the bar properties can be constrained from studying the properties of the butterfly-feature in the kinematics of stars in Milky Way-like systems. I will further discuss the potential caveat of inferring Milky Way’s bar properties by using the stellar kinematic information from the Gaia DR3 without properly accounting for the observational uncertainties.
Hunt for a robust kinematic diagnostic to constrain the bar properties in the Milky Way
Mercredi 1er juillet 2026
de
14:00 à
15:00
Conference room, building 17
