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SUMMARY:Robustness of Molecular Detections Using High-Resolution Transmiss
 ion Spectroscopy - Connor Cheverall
DTSTART:20220608T124500Z
DTEND:20220608T131500Z
UID:TALK175508@talks.cam.ac.uk
CONTACT:Hannah Uebler
DESCRIPTION:In recent years\, high-resolution transmission spectroscopy ha
 s emerged as one of the most successful techniques for detecting chemicals
  in transiting exoplanetary atmospheres. Despite many molecular detections
  to date\, concerns have been raised about robustness when removing tellur
 ic and stellar features from the observed spectra\, a step known as detren
 ding. A robust detrending method has yet to be agreed upon\, leaving previ
 ous detections inconsistent and sometimes irreproducible. We examine how o
 verfitting detrending parameters can falsely amplify detection significanc
 es\, and propose a robust methodology to select these parameters without i
 ntroducing bias. To do this\, we use CARMENES observations of the hot Jupi
 ter HD189733b as a case study to investigate the robustness of different d
 etrending optimisations. We find that selecting detrending parameters by o
 ptimising the difference between a signal-injected cross-correlation funct
 ion and the observed cross-correlation function is robust against noise an
 d spurious signals. On the other hand\, optimising without this subtractio
 n\, as is often done\, can induce spurious peaks and inflate detection sig
 nificances. We reproduce previous detections with decreased significances 
 reflecting more robust detrending. Our findings provide a robust framework
  for future homogeneous molecular surveys of exoplanetary atmospheres usin
 g high-resolution transmission spectroscopy.\n
LOCATION:The Hoyle Lecture Theatre + Zoom 
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