Abstract Details

Name: Silpa Sasikumar
Affiliation: NCRA-TIFR
Conference ID: ASI2020_70
Title : Understanding radio outflows in radio-quiet quasars
Authors and Co-Authors : Silpa Sasikumar, Preeti Kharb, Luis C. Ho, C. M. Harrison, C. H. Ishwara-Chandra, M. E. Jarvis
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : The origin of radio emission in radio-quiet quasars (RQQs) is poorly understood. Possible origins include: thermal free-free radio emission from HII regions, non-thermal radio emission from starburst superwinds, coronal emission due to magnetic heating of the corona located above the accretion disc, free-free emission from optically thin ionized plasma, compact or low-powered radio jets on milli-arcsecond scales, AGN winds, and winds driven by a combination of both starbursts and AGN. In order to understand the dominant radio emission mechanism in RQQs, we have carried out a pilot low-frequency survey using upgraded GMRT (uGMRT) for 22 sources from the Palomar Green quasar sample. Our uGMRT observations have clearly detected copious amounts of low frequency diffuse emission; some of which could be related to a previous AGN activity episode. The spectral index images of these sources suggest an AGN jet origin for the steep radio spectrum, instead of AGN/starburst winds, as suggested in the literature. We also try to explore the correlations between radio, accretion and molecular gas properties, since a decent number of our sample already have X-ray and ALMA data available. We will present the results from our pilot study.