Imaging sub-milliarcsecond stellar features with intensity interferometry using air Cherenkov telescope arrays

TL;DR

This paper explores the use of air Cherenkov telescope arrays for stellar intensity interferometry, demonstrating the potential to image complex stellar features with high resolution at short wavelengths.

Contribution

It introduces a method for model-independent stellar image reconstruction using air Cherenkov arrays, focusing on imaging stars with localized temperature variations.

Findings

Hot stars with localized regions as small as 0.1 mas can be imaged at 400 nm.

Good (u, v)-plane coverage enables model-independent image recovery.

Phase retrieval techniques enhance the imaging capabilities of SII with Cherenkov arrays.

Abstract

Recent proposals have been advanced to apply imaging air Cherenkov telescope arrays to stellar intensity interferometry (SII). Of particular interest is the possibility of model-independent image recovery afforded by the good (u, v)-plane coverage of these arrays, as well as recent developments in phase retrieval techniques. The capabilities of these instruments used as SII receivers have already been explored for simple stellar objects, and here the focus is on reconstructing stellar images with non-uniform radiance distributions. We find that hot stars (T > 6000 K) containing hot and/or cool localized regions (T \sim 500 K) as small as \sim 0.1 mas can be imaged at short wavelengths ({\lambda} = 400 nm).