The infrared imaging spectrograph (IRIS) for TMT: overview of innovative science programs

Abstract

IRIS (InfraRed Imaging Spectrograph) is a fust light near-infrared diffraction limited imager and integral field spectrograph being designed for the future Thirty Meter Telescope (TMT). IRIS is optimized to perform astronomical studies across a significant fraction of cosmic time, from our Solar System to distant newly formed galaxies (Barton et al. [1]). We present a selection of the innovative science cases that are unique to IRIS in the era of upcoming space and ground-based telescopes. We focus on integral field spectroscopy of directly imaged exoplanet atmospheres, probing fundamental physics in the Galactic Center, measuring I 0 4 to 10 10 M 0 supermassive black hole masses, resolved spectroscopy of young star-forming galaxies (1 < z < 5) and first light galaxies (6 < z < 12), and resolved spectroscopy of strong gravitational lensed sources to measure dark matter substructure. For each of these science cases we use the IRIS simulator (Wright et al. [2], Do et al. [3]) to explore IRIS capabilities. To highlight the unique IRIS capabilities, we also update the point and resolved source sensitivities for the integral field spectrograph (IFS) in all five broadband filters (Z, Y, J, H, K) for the finest spatial scale of 0.004" per spaxel. We briefly discuss future development plans for the data reduction pipeline and quicklook software for the IRIS instrument suite.

The InfraRed Imaging Spectrograph (IRIS) for TMT: photometric characterization of anisoplanatic PSFs and testing of PSF-Reconstruction via AIROPA

“…The quality of the imager photometric performance is a function of the Signal-to-Noise Ratio (SNR) of an observed source within the field of view, as well as the observational parameters, atmospheric quality, and performance of the Narrow-Field Infrared Adaptive Optics System (NFIRAOS). 5,6 To simulate these effects we use the IRIS data simulator [7][8][9] package in conjunction with imager Point Spread Functions (PSFs) simulated by the NFIRAOS team to indicate Strehl ratio, spatial atmospheric effects, and spatial asymmetries in flux distribution. Because the field of view of the imager is large relative to the spatial effects of atmospheric turbulence across the field of view, variations in the PSF caused by anisoplanatism are expected even with the best possible performance of NFIRAOS.…”

The Infrared Imaging Spectrograph (IRIS) for TMT: advancing the data reduction system

“…[6][7][8] Figure 5 shows preliminary simulations of the Hubble eXtreme Deep Field (XDF). 9 We are currently developing a module within the IRIS simulator 3,4,10,11 to add the functionality of simulating science fields with the low dispersion mode to investigate observing and calibration strategy as well as sensitivity limits.…”

The InfraRed Imaging Spectrograph (IRIS) for TMT: photometric precision and ghost analysis

“…In the IRIS simulator, we assume the following sources of noise in the IRIS imager: readnoise of 5 e − , dark current of 0.002 e − , and Poisson noise from sources, background (telescope, instrument, and atmospheric), and dark current. [11][12][13] We note that systematic error sources are not included in the simulation. Additionally, we use a single PSF per bandpass for these simulations, which does not represent a fair comparison to real observations.…”

“…We use the IRIS data simulator [11][12][13] to analyze the photometric effects of ghost images on the IRIS imager. Using the current specifications for IRIS's optical design and filter characteristics, we simulate the effects of the optical system, IRIS throughputs, sky background, ghosts, and Poisson noise.…”