Missing flux in VLBI observations of SiO maser at 7mm in IRC+10011

TL;DR

This study investigates the missing flux issue in VLBI SiO maser observations at 7mm in IRC+10011, revealing that most of the flux is in numerous very weak maser components, thanks to high sensitivity imaging.

Contribution

It demonstrates that the missing flux in VLBI SiO maser observations is primarily due to numerous weak components, using high sensitivity and resolution data.

Findings

Most missing flux is in very weak maser components

High dynamic range imaging reveals detailed maser structure

Supports the idea that flux is divided into many weak features

Abstract

VLBI observations of SiO masers recover at most 40-50% of the total flux obtained by single dish observations at any spectral channel. Some previous studies seems to indicate that, at least, part of the lost flux is divided up into many weak components rather than in a large resolved emission area. Taking benefit of the high sensitivity and resolution of the HSA, we investigate the problem of the missing flux in VLBI observations of SiO maser emission at 7mm in the AGB stars and obtain a high dynamic range map of IRC+10011. We conclude that the missing flux is mostly contained in many very weak maser components.