Abstract

NOS: NIRISS Optical Simulator

Jonathan St-Antoine (University of Montreal)

Jonathan St-Antoine (UdeM), Loïc Albert (UdeM), René Doyon (UdeM), Philippe Vallée (UdeM), Étienne Artigau (UdeM), Olivier Hernandez (UdeM), Simon Thibault (ULaval)

The Near Infrared Imager and Slitless Spectrograph (NIRISS) Optical Simulator (NOS) is a laboratory simulation of the single-object slitless spectrograph and aperture masking interferometry modes of the NIRISS instrument onboard the James Webb Space Telescope (JWST). A transiting exoplanet can be simulated by periodically eclipsing a small portion (1% - 10ppm) of a super continuum laser source (0.7 micron - 2.9 micron) with a dichloromethane filled cell. Dichloromethane exhibits multiple absorption features in the near infrared domain hence the net effect is analogous to the atmospheric absorption features of an exoplanet transiting in front of its host star. The NOS uses an HAWAII-2RG and an ASIC controller cooled to cryogenic temperatures. A separate photometric beacon provides a flux reference to monitor laser variations. The telescope jitter can be simulated using a high-resolution motorized pinhole placed along the optical path. Laboratory transiting spectroscopy data produced by the NOS will be used to refine analysis methods, characterize the noise due to the jitter, to characterize the noise floor and to develop better observation strategies. We report in this paper the second exoplanet transit event simulated by the NOS. The performance is currently limited by relatively high thermal background in the system and high frequency temporal variations of the continuum source.

Mode of presentation: poster