[seminar] Astro Journal Club on 8 April

[Oskari Miettinen]

Dear all,

The Astro Journal Club will be held tomorrow at 10:15 in the seminar room
F-201 of the Physics Department. This time we will discuss about
radio-loud active galactic nuclei.

Presenter: Nikola Baran
Paper title: Radio-AGN Feedback: When the Little Ones were Monsters
Authors: Williams, W. L., and Röttgering, H. J. A.

Summary:
We present a study of the evolution of the fraction of radio-loud active
galactic nuclei (AGN) as a function of their host stellar mass. We make
use of two samples of radio galaxies: one in the local universe, 0.01 < z
< 0.3, using a combined SDSS-NVSS sample and one at higher redshifts, 0.5
< z < 2, constructed from the VLA-COSMOS_DEEP Radio Survey at 1.4 GHz and
a Ks-selected catalogue of the COSMOS/UltraVISTA field. We observe an
increase of more than an order of magnitude in the fraction of lower mass
galaxies (M* < 10^{10.75}$ Msun) which host Radio-Loud AGN with radio
powers P_{1.4GHz} > 10^{24} W/Hz at z ~ 1-2 while the radio-loud fraction
for higher mass galaxies (M* > 10^{11.25} Msun) remains the same. We argue
that this increase is driven largely by the increase in cold or radiative
mode accretion with increasing cold gas supply at earlier epochs. The
increasing population of low mass Radio-Loud AGN can thus explain the
upturn in the Radio Luminosity Function (RLF) at high redshift which is
important for understanding the impact of AGN feedback in galaxy
evolution.

Link to the paper: http://adsabs.harvard.edu/abs/2015arXiv150308927W

See you all tomorrow!

Best wishes,
Oskari