Speaker
Description
Characterization of cooler atmospheres of super-Earths and Neptune sized objects at low-resolution is often thwarted by the presence of clouds, hazes and aerosols which effectively flatten the transmission spectra. High-Resolution Spectroscopy (HRS) presents an opportunity to overcome this limitation by having the ability to detect molecular species whose spectral line cores extend above the level of clouds in these atmospheres. We analyse High-Resolution observations of the warm Neptune GJ 3470b taken over one transit using CARMENES (R ~ 80400) and two transits using GIANO (R ~ 50000) and look at the possibility of signatures for first H$_2$O in isolation and then H$_2$O and CH$_4$ together. We find a tentative detection of H$_2$O using either the peak of the cross correlation signal or a cross-correlation-to-likelihood metric while comparing it to just the best fit model, when all three nights are combined. The detection becomes even weaker when both H$_2$O and CH$_4$ are used for abundance and cloud deck layer values close to the best fit model. This decrease is in line with results from the Hubble Space Telescope, at much lower resolution. However, accounting for the effects of data analysis on the compared model produces a strong detection close to the expected exoplanet position using just one night of CARMENES. Following this, we are planning to use a Bayesian retrieval tool to put simultaneous constraints on the abundance of molecular species and the pressure of the cloud top-deck. Such a tool will also allow us to directly compare/combine our results with published HST observations.
