Hints of bar growth from bulges and density profiles

Bars have long been predicted to be slowing down by transferring angular momentum to their dark matter halos, and in the process growing. While this predicts that bars are slowly rotating, the number of actually slow bars known is very low. Bars in massive galaxies also form boxy/peanut-shaped bulges. Although B/P bulges have long been observed, their formation does not require the bar to slow down to form, but become more prevalent in slow bars. So do bars actually slow down? In this presentation I discuss observational evidence that bars are growing, and therefore necessarily slowing down. I will also present new results on the formation of B/P bulges from the Illustris TNG50 simulation that informs our understanding of how B/P bulges form, and what it means for bar formation and evolution.