SCORPIO: A deep survey of Radio Emission from the stellar life-cycle

TL;DR

The SCORPIO project conducted a deep 1.4 GHz radio survey of a stellar region, revealing numerous sources, including stellar and galactic objects, with unprecedented sensitivity and resolution, to better understand stellar radio emission across all evolutionary stages.

Contribution

This is the first deep, unbiased radio survey targeting stellar objects across the stellar life-cycle, providing high-resolution images and a large catalog of sources for stellar radio emission studies.

Findings

Approximately 600 point-like sources detected in the pilot field.

About 50% of sources are likely stellar or galactic in nature.

Discovery of bubble-like structures with high sensitivity images.

Abstract

Radio emission has been detected in a broad variety of stellar objects from all stages of stellar evolution. However, most of our knowledge originates from targeted observations of small samples, which are strongly biased to sources which are peculiar at other wavelengths. In order to tackle this problem we have conducted a deep 1.4 GHz survey by using the Australian Telescope Compact Array (ATCA), following the same observing setup as that used for the Australia Telescope Large Area Survey (ATLAS) project, this time choosing a region more appropriate for stellar work. In this paper, the SCORPIO project is presented as well as results from the pilot experiment. The achieved rms is about 30 /uJy and the angular resolution ~10 arcsec. About six hundred of point-like sources have been extracted just from the pilot field. A very small percentage of them are classified in SIMBAD or the NASA/IPAC Extragalactic Database (NED). About 80 % of the extracted sources are reported in one of the inspected catalogues and 50 % of them appears to belong to a reddened stellar/galactic population. The evaluation of extragalactic contaminants is very difficult without further investigations. Interesting results have been obtained for extended radio sources that fall in the SCORPIO field. Many bubble-like structures have been found, some of which are classified at other wavelengths. However, for all of these sources, our project has provided us with images of unprecedented sensitivity and angular resolution at 2.1 GHz.