New NIR spectro-polarimetric modes for the SCExAO instrument

Polarization Differential Imaging (PDI) is one of the most productive modes of current high-contrast imagers. Dozens of new protoplanetary, transition and debris disks were imaged recently for the first time, helping us understand the processes of planet formation, and giving clues on the mass of potential planets inside these disks, even if they cannot be imaged directly. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is equipped with a fast visible dual-camera polarimetric module, VAMPIRES, already producing valuable scientific observations of protoplanetary disks and dust shells. In addition, we recently commissioned two new polarimetric modules in the infrared. The first one is a spectro-polarimetric mode using the CHARIS Integral Field Spectrograph (IFS). A Wollaston prism was added in front of the IFS, reducing the field-of-view to 2x1 arcsec to accommodate for the imaging of both polarizations on the same detector without sacrificing the spectral resolution of the instrument, in any of its spectral modes. The second module, similar to VAMPIRES, uses a low-noise high frame rate C-RED ONE camera combined with a Ferroelectric Liquid Crystal (FLC) device to modulate and record the polarization at high-speed, freezing effectively the atmospheric speckles for higher precision. We present on-sky results of the new polarimetric capabilities taken during the commissioning phase. In addition, we show future capabilities that are already scheduled to increase the performance of these modules, especially the addition of non-redundant masks, as well as a polarimetric vector Apodizing Phase Plate (vAPP) coronagraph.

[1]  Donald N. B. Hall,et al.  Measurements of Speckle Lifetimes in Near-infrared Extreme Adaptive Optics Images for Optimizing Focal Plane Wavefront Control , 2018, Publications of the Astronomical Society of the Pacific.

[2]  G. Perrin,et al.  The Subaru Coronagraphic Extreme Adaptive Optics System: Enabling High-Contrast Imaging on Solar-System Scales , 2015, 1507.00017.

[3]  Michael J. Escuti,et al.  Fully broadband vAPP coronagraphs enabling polarimetric high contrast imaging , 2018, Astronomical Telescopes + Instrumentation.

[4]  Peter G. Tuthill,et al.  A close halo of large transparent grains around extreme red giant stars , 2012, Nature.

[5]  Frantz Martinache,et al.  Subaru Coronagraphic eXtreme Adaptive Optics: on-sky performance of the asymmetric pupil Fourier wavefront sensor , 2016, Astronomical Telescopes + Instrumentation.

[6]  Shane Jacobson,et al.  Concept and science of HiCIAO: high contrast instrument for the Subaru next generation adaptive optics , 2006, SPIE Astronomical Telescopes + Instrumentation.

[7]  E. Kokubo,et al.  DIRECT IMAGING OF FINE STRUCTURES IN GIANT PLANET-FORMING REGIONS OF THE PROTOPLANETARY DISK AROUND AB AURIGAE , 2011, 1102.4408.

[8]  Julien Lozi,et al.  High-contrast Hα imaging with Subaru/SCExAO + VAMPIRES , 2020, Journal of Astronomical Telescopes, Instruments, and Systems.

[9]  John D. Monnier,et al.  Multiple Spiral Arms in the Disk around Intermediate-mass Binary HD 34700A , 2019, The Astrophysical Journal.

[10]  Andrew W. Serio,et al.  First light of the Gemini Planet Imager , 2014, Proceedings of the National Academy of Sciences.

[11]  Frantz Martinache,et al.  SCExAO, an instrument with a dual purpose: perform cutting-edge science and develop new technologies , 2018, Astronomical Telescopes + Instrumentation.

[12]  Frantz Martinache,et al.  Scientific design of a high contrast integral field spectrograph for the Subaru Telescope , 2012, Other Conferences.

[13]  Shane Jacobson,et al.  Visible and Near-infrared Laboratory Demonstration of a Simplified Pyramid Wavefront Sensor , 2019, Publications of the Astronomical Society of the Pacific.

[14]  O. Guyon,et al.  The VAMPIRES instrument: imaging the innermost regions of protoplanetary discs with polarimetric interferometry , 2014, 1405.7426.

[15]  Olivier Guyon,et al.  Overview of the SAPHIRA detector for adaptive optics applications , 2018, Journal of Astronomical Telescopes, Instruments, and Systems.

[16]  C. Fabron,et al.  SPHERE: a planet finder instrument for the VLT , 2006, Astronomical Telescopes + Instrumentation.

[17]  Frantz Martinache,et al.  Design of the CHARIS integral field spectrograph for exoplanet imaging , 2013, Optics & Photonics - Optical Engineering + Applications.