Synthetic Spitzer IRAC phase curves from the Newtonian forcing model. The solid lines are calculated from the model presented in Mayne et al. (2014a) and Sect. 3 using ATMO, the dashed lines are the synthetic phase curves from Fortney et al. (2006), which are based on the models of Cooper & Showman (2005, 2006) using the same Newtonian forcing scheme. The models have been integrated over the IRAC bands using the filter functions. The data points are from Zellem et al. (2014) (►), Diamond-Lowe et al. (2014) (■) and Evans et al. (2015) (♦). The best fit to the observed 4.5 μm phase curve from Zellem et al. (2014) is shown as a solid black line, the grey shaded area is the 1σ uncertainty for the offset of the observed planet to star flux ratio.