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High-resolution spectroscopy has provided a wealth of information about theclimate and composition of ultra-hot Jupiters. However, the 3D structure oftheir atmospheres makes observations more challenging to interpret,necessitating 3D forward-modeling studies. In this work, we modelphase-dependent thermal emission spectra of the archetype ultra-hot JupiterWASP-76b to understand how the line strengths and Doppler shifts of Fe, CO,H$_2$O, and OH evolve throughout the orbit. We post-process outputs of theSPARC/MITgcm global circulation model with the 3D Monte-Carlo radiativetransfer code gCMCRT to simulate emission spectra at 36 orbital phases. We thencross-correlate the spectra with different templates to obtain CCF and$K_{\text{p}}$$-$$V_{\text{sys}}$ maps. For each species, our models produceconsistently negative $K_{\text{p}}$ offsets in pre- and post-eclipse, whichare driven by planet rotation. The size of these offsets is similar to theequatorial rotation velocity of the planet. Furthermore, we demonstrate how theweak vertical temperature gradient on the nightside of ultra-hot Jupiters mutesthe absorption features of CO and H$_2$O, which significantly hampers theirdetectability in pre- and post-transit. We also show that the $K_{\text{p}}$and $V_{\text{sys}}$ offsets in pre- and post-transit are not always a measurefor the line-of-sight velocities in the atmosphere. This is because thecross-correlation signal is a blend of dayside emission and nightsideabsorption features. Finally, we highlight that the observational uncertaintyin the known orbital velocity of ultra-hot Jupiters can be multiple km/s, whichmakes it hard for certain targets to meaningfully report absolute$K_{\text{p}}$ offsets.

From pre-transit to post-eclipse: investigating the impact of 3D  temperature, chemistry, and dynamics on high-resolution emission spectra of  the ultra-hot Jupiter WASP-76b