Oral Presentation Astronomical Society of Australia Annual Scientific Meeting including HWWS 2013

The cold gas in nearby radio galaxies with HIPASS (#56)

James R Allison 1 , Elaine M Sadler 1 2
  1. University of Sydney, Sydney, NSW, Australia
  2. ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Sydney, NSW, Australia

Absorption of 21cm wavelength radiation in neutral atomic hydrogen (HI) provides the observer with a powerful tool to map the line-of-sight kinematics of neutral gas in galaxies. Observations of the 21cm transition have been used to observe highly broadened and doppler-shifted lines towards radio-loud active galactic nuclei (AGNs). The study of such absorption lines provides direct evidence of the presence of cold neutral gas in/out-flows, indicating that the interaction between the AGN with the interstellar medium is common.

Using a novel technique, developed for future all-sky absorption surveys with the Square Kilometer Array pathfinders1, we have successfully detected cold HI gas in nearby radio galaxies in the first-generation HI Parkes All-Sky Survey (HIPASS). I will present results from this search and follow-up observations with the Australia Telescope Compact Array (ATCA). Furthermore, I will discuss our recent observations of the cold HI gas feeding compact young radio galaxies with both ATCA and the Australian Long Baseline Array2,3

  1. Allison J. R., Sadler E. M., Whiting M. T., 2012a, PASA, 29, 221
  2. Allison J. R., Curran S. J., Emonts B. H. C., Geréb K., Mahony E. K., Reeves S., Sadler E. M., Tanna A., Whiting M. T., Zwaan M. A., 2012b, MNRAS, 423, 2601
  3. Allison J. R., Curran S. J., Sadler. E. M., Reeves S. N., 2013, MNRAS, 430, 157