Research
Can bars form in presence of hot thick disk?
The dynamical role of the (geometrically) thick disc in the bar formation and evolution is not fully understood till date. In a recent work, we investigate the effect of thick discs in the formation and evolution of bars by means of a suite of N-body models of (kinematically cold) thin and (kinematically hot) thick discs. We systematically varied the mass fraction of the thick disc, the thin-to-thick disc scale length ratio, and the thick disc scale height to examine the bar formation under diverse dynamical scenarios. Bars form almost always in our models, even in the presence of a massive thick disc. For more details, see Ghosh+2023,A&A, 674, 128
Do bars buckle in presence of hot thick disk?
In a recent work, we investigate the effect of thick discs in the formation and evolution of boxy/peanut (b/p) bulge by means of a suite of N-body models of (kinematically cold) thin and (kinematically hot) thick discs. We systematically varied the mass fraction of the thick disc, the thin-to-thick disc scale length ratio, and the thick disc scale height to examine the b/p formation under diverse dynamical scenarios. For more details, see Ghosh+2023, A&A, in press
Influence of bars in action-based dynamical modelling of Milky Way-like galaxies
Action-based dynamical modelling, using stars as dynamical tracers, is an excellent diagnostic to estimate the underlying axisymmetric matter distribution of the Milky Way. However, the Milky Way's bar causes non-axisymmetric resonance features in the stellar disk. In a recent work, we systematically quantify the robustness of action-based modelling in the presence of a bar (with different strengths). For more details, see Ghosh+2023, MNRAS, 533, 991
Vertical breathing motion driven by spiral arms in Milky Way-like galaxies
Gaia Data Release 2 (DR2) has revealed that stars in the Solar vicinity and beyond display a vertical breathing motion, i.e., stars on both sides of the Galactic mid-plane are moving coherently towards or away from it (analogous to human respiration). In a series of recent works, we have shown that vertically-extended spiral density waves (either tidally-induced or formed by internal gravitational instability) can drive such vertical breathing motion; thereby strengthening the case that the observed breathing motions in the Milky Way are likely driven by spiral density waves. For more details, see Ghosh+2022, Kumar+2022, Khachaturyants+2022.
Excitation of m=1 lopsidedness in minor merger of galaxies
In a recent work, we investigated the excitation of an m = 1 lopsidedness in host galaxies during minor mergers while choosing a set of 1:10 merger models (with varying orbital configurations, morphology of the host galaxy) from the GalMer galaxy merger library. We show that a minor merger triggers a prominent m = 1 lopsidedness in stars of the host galaxy. The strength of the m = 1 lopsidedness undergoes a transient amplification phase after each pericenter passage of the satellite. However, once the merger happens, and the post-merger remnant readjusts itself, the lopsidedness disappears in short time-scale (~ 500 - 850 Myr). For more details, see Ghosh+2022, MNRAS, 511, 5878