Multi-wavelength observations of the Perseus cloud and associated bubbles. Herschel contours of the Perseus, Taurus, and California clouds are shown in blue (denoted in the top-left panel as Per, Tar, and Cal, respectively). The Per-Tau shell (Bialy et al. 2021) is depicted as a white dot-dashed circle and the Per2 shell is approximated as the green dashed circle. Top-left panel: Ha observations (Finkbeiner 2003). Top-right panel: dust observations from the Planck Space Observatory. Lower-left panel: H I observations at a velocity of −1.2 km s⁻¹ from HI4PI. Lower-right panel: composite CO survey of Dame et al. (2001).