ASCENT - A balloon-borne hard X-ray imaging spectroscopy telescope using transition edge sensor microcalorimeter detectors

TL;DR

ASCENT is a proposed balloon-borne X-ray telescope using advanced microcalorimeter detectors to achieve high-resolution imaging spectroscopy of supernova remnants, aiming to answer key questions about supernova explosion mechanisms and element synthesis.

Contribution

It introduces a novel balloon-borne mission concept employing transition edge sensor detectors with significantly improved energy resolution for detailed supernova remnant studies.

Findings

Demonstrated 55 eV energy resolution at 97 keV with microcalorimeter detectors.

Proposed an 8-16 times improvement over NuSTAR for gamma-ray spectroscopy.

Aims to resolve gamma-ray line features to study supernova explosion physics.

Abstract

Core collapse supernovae are thought to be one of the main sources in the galaxy of elements heavier than iron. Understanding the origin of the elements is thus tightly linked to our understanding of the explosion mechanism of supernovae and supernova nucleosynthesis. X-ray and gamma-ray observations of young supernova remnants, combined with improved theoretical modeling, have resulted in enormous improvements in our knowledge of these events. The isotope ${}^{44}$Ti is one of the most sensitive probes of the innermost regions of the core collapse engine, and its spatial and velocity distribution are key observables. Hard X-ray imaging spectroscopy with the Nuclear Spectroscopic Telescope Array (NuSTAR) has provided new insights into the structure of the supernova remnant Cassiopeia A (Cas A), establishing the convective nature of the supernova engine. However, many questions about the details of this engine remain. We present here the concept for a balloon-borne follow-up mission called ASCENT (A SuperConducting ENergetic x-ray Telescope). ASCENT uses transition edge sensor gamma-ray microcalorimeter detectors with a demonstrated 55 eV Full Width Half Maximum (FWHM) energy resolution at 97 keV. This 8--16-fold improvement in energy resolution over NuSTAR will allow high resolution imaging and spectroscopy of the ${}^{44}$Ti emission. This will allow a detailed reconstruction of gamma-ray line redshifts, widths, and shapes, allowing us to address questions such as: What is the source of the neutron star "kicks"? What is the dominant production pathway for ${}^{44}$Ti? Is the engine of Cas A unique?