An exposure time calculator for high-contrast polarimeters

Abstract

We present an exposure time calculator (ETC) developed for polarimetric observing modes for two next-generation high-contrast direct imaging instruments planned for the W. M. Keck Observatory: SCALES1 (Santa Cruz Array of Lenslets for Exoplanet Spectroscopy), a low-resolution mid-infrared integral field spectrograph; and a future polarimetric observing mode for NIRC2, the near-infrared adaptive optics (AO) supported high-contrast direct imager currently on the Keck Observatory. In addition to producing estimates of companion signal-to-noise ratios (SNR, see Fig. 2a), the ETC calculates the polarization fraction that would be detected with a user-specific SNR in a given exposure time (see Fig. 2b). The ETC includes a graphical user interface and is packaged as a polarimetry add-on to the PSI-Red thermal imaging module of PSISim, an instrument performance simulation tool for the Planetary Systems Imager2 - a modular suite of AO-supported instruments planned for the Thirty Meter Telescope.