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Astrophysics Colloquium

A New Technique for Precision Color Photometry: Eliminating all Non-Common Path Errors including Atmospheric Scintillation
Presented by Darren DePoy
Texas A&M University

Thursday, March 19, 2020
Virtual Event starts at 11:00 A.M.

Atmospheric turbulence and a dynamic instrument environment have prevented astronomers from achieving space-based photometric precisions from the ground. We present here a new technique, self-referencing discrete slitless spectroscopy (SRDSS), capable of achieving space-based photometric color precisions insensitive to most atmospheric and environmental disturbances with spectral resolutions of R = 5-60 using current technology. We discuss the design, capabilities and limitations of the SRDSS method. We demonstrate photometric color precisions on-sky with errors on-par with space-based measurements. Specifically, we achieve ground-based photometric measurements of bright stars with precisions dominated by photon noise and well below the atmospheric scintillation limit which is typically three times larger than the photon noise for our brightest target. Further, we discuss how this technique eliminates all non-common path errors, not just atmospheric scintillation, but other errors such instrumental jitter, flexure, vignetting and distortion, telescope tracking and stability errors and atmospheric transparency and airmass variations. We illustrate the SRDSS method by measuring two colors during a WASP3-b transit. Applications of the SRDSS method to exoplanet transit spectroscopy surveys, exo-earth spectra and supernova follow-up are also discussed. We calculate that a SRDSS instrument could survey ∼200 exoplanet transit spectra in 2 years on a small (2.7 meter) telescope with sensitivity to exoplanet atmospheric features comparable with those achieved with the Hubble Space Telescope. We show that SRDSS can be used to obtain spectra of earth-like planets from the next generation of ground-based observatories. Further, we note that SRDSS may be optimal for identifying which LSST supernovae are most interesting for follow-up.

JPL Contacts: Vanessa Bailey (4-2034) and Leonidas Moustakas (3-5095)

SVCP Astrophysics

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