New program to study nuclear gas in nearby radio-loud galaxies
Our understanding of the physical mechanisms behind the formation of stars and galaxies has greatly improved over the last couple of decades but new technology in hardware and software will keep driving these endeavours further still. These new technologies will be needed to, for instance, verify whether all massive galaxies are sources of radio emission, fuelled by a Black Hole located in the galactic centre.
As the first stage of a new research project, a newly published paper by a Swinburne University based CAASTRO member, Professor Jeremy Mould, and his Australian and overseas colleagues describes their analysis of nuclear activity in galaxies close to our own (“Infrared spectroscopy of nearby radio active elliptical galaxies”, in The Astrophysical Journal – Supplement Series 203 on 1 November 2012). As one of the first objectives of the project, the research team looked at a potential correlation between the growth of the central Black Hole and the rate of star formation in the galaxy. They conducted their survey of infrared emission lines using spectrographs on the Palomar and Kitt Peak National Observatories in the US, targeting suitably close and radio active galaxies (previously catalogued in a 2011 publication).
For a fraction of these galaxies, they found nuclear spectra and infrared emission line nuclei with six times the average radio emission at a given stellar mass. This means that the Black Holes in these galaxies are currently growing by accreting matter from its surrounding gas disk. The researchers further calculated a star formation rate of 0.4 Solar Masses per year.
Jeremy Mould, Tristan Reynolds, Tony Readhead,David Floyd, Buell Jannuzi, Garret Cotter, Laura Ferrarese, Keith Matthews, David Atlee, Michael Brown in ApJS 203-14