CHESS: an Innovative Concept for High-Resolution, Far-UV Spectroscopy

TL;DR

This paper introduces CHESS, a high-resolution, high-throughput far-UV spectrograph designed for space telescopes, demonstrating its capabilities through sounding rocket flights and studying interstellar medium transitions.

Contribution

It presents the design, fabrication, and calibration of CHESS, a novel high-resolution UV spectrograph, and reports on its performance and scientific results from initial flights.

Findings

Successful demonstration of diffraction grating and detector technologies for far-UV spectroscopy.

Detection of atomic-to-molecular transitions in interstellar clouds.

Validation of CHESS as a promising instrument for future space telescopes.

Abstract

The space ultraviolet (UV) is a critical astronomical observing window, where a multitude of atomic, ionic, and molecular signatures provide crucial insight into planetary, interstellar, stellar, intergalactic, and extragalactic objects. The next generation of large space telescopes require highly sensitive, moderate-to-high resolution UV spectrograph. However, sensitive observations in the UV are difficult, as UV optical performance and imaging efficiencies have lagged behind counterparts in the visible and infrared regimes. This has historically resulted in simple, low-bounce instruments to increase sensitivity. In this study, we present the design, fabrication, and calibration of a simple, high resolution, high throughput far-UV spectrograph - the Colorado High-resolution Echelle Stellar Spectrograph (CHESS). CHESS is a sounding rocket payload to demonstrate the instrument design for the next-generation UV space telescopes. We present tests and results on the performance of several state-of-the-art diffraction grating and detector technologies for far-UV astronomical applications that were flown aboard the first two iterations of CHESS. The CHESS spectrograph was used to study the atomic-to-molecular transitions within translucent cloud regions in the interstellar medium (ISM) through absorption spectroscopy. The first two flights looked at the sightlines towards alpha Virgo and epsilon Persei, and flight results are presented.