VLBA24A-069

Neutral gas in the nuclear regions of PKS 0428+20

Abstract

We propose to conduct spectroscopic and continuum observations at L band with the VLBA+GBT towards the GPS source AGN, PKS 0428+20 (z = 0.219). The system shows a compact and bright southern jet component, and a diffused northern component, along with a significant core. HI 21cm absorption is detected in WSRT observations, which shows broad redshifted (fast inflowing/accreting gas) features. The column densities are indicative of high gas density, sufficient to be in ram-pressure equilibrium with the expanding jet. We aim to test the hypothesis that the southern jet lobe is likely frustrated by the dense accreting gas. We aim to conduct high resolution observations to trace the HI gas density distribution, and gradient in velocity, and to understand the origins of various pc scale components. We request VLBA+GBT time of 16 hrs in the L band.

Investigators

Name	Institution
Simon Weng	Sydney, University of
Renzhi Su	Shanghai Astronomical Observatory, CAS; Zhejiang Lab
Vanessa Moss	Netherlands Institute for Radio Astronomy; Sydney, University of
Emily Kerrison	Sydney, University of
Hyein Yoon	Sydney, University of
Matthew Whiting	Australia Telescope National Facility
Elizabeth Mahony	Netherlands Institute for Radio Astronomy; Sydney, University of; Commonwealth Scientific and Industrial Research Organisation
Elaine Sadler	Sydney, University of
Aditya JNHS *	Sydney, University of; Shanghai Astronomical Observatory, CAS
GBT Operator	Green Bank Observatory

* indicates the PI