First light of the Integral Field Unit of GRIS on the GREGOR solar telescope

TL;DR

The paper reports the successful integration of an image-slicer based Integral Field Unit into the GREGOR solar telescope's spectrograph, enabling high-resolution, high-cadence 2D spectropolarimetry of solar features in the near-infrared.

Contribution

This work introduces a novel IFU for the GREGOR telescope that allows simultaneous 2D spectropolarimetric observations, serving as a prototype for future European Solar Telescope instruments.

Findings

Successful installation and commissioning of the IFU in 2018.

Enhanced capability for high-resolution, high-cadence solar observations.

Potential for detailed studies of solar plasma and magnetic field dynamics.

Abstract

An Integral Field Unit (IFU) based on image-slicers has been added to the GREGOR Infrared Spectrograph (GRIS). This upgrade to the instrument makes possible 2D spectropolarimetry in the near-infrared by simultaneously recording the full Stokes profiles of spectral lines (in a given spectral interval) at all the points in the field of view. It provides high-cadence spectropolarimetric observations at the instrument's high spatial resolution and high polarization sensitivity at the GREGOR solar telescope. The IFU is ideal for observing the polarized spectrum of fast-evolving solar features at high spatial and spectral resolutions. The high observing cadence opens the possibility of time-series observations. The analysis of observations to this level of accuracy is essential for understanding the complex dynamics and interactions of solar plasma and magnetic fields. The image slicer of the IFU has eight slices of width 100 micron, covering a total field of view of 6" x 3". It was designed and built within the framework of the European projects SOLARNET and GREST, as a prototype for future instruments of the European Solar Telescope (EST) and was integrated into GRIS. After two commissioning campaigns in 2017 and 2018, the IFU was finally installed at the end of September 2018 and offered to all observers who use the telescope.