PhD Defense Pieter van Oers

Some black holes are bright in radio while others are not. In this thesis we explore why, relating the radio emission to the relativistic jet phenomenon and examining how the emission behaves across the entire observed, 8 magnitude wide black hole mass scale.

First we model detailed broadband spectra of the high accretion rate stellar mass black hole GRS1915+105 as well as the low accretion rate supermassive black hole in M94 with an outflow dominated model. We see how jets appear from radio to X-ray energies and gain understanding of the underlying physical processes that produce the observed emission.

In the second half of this thesis we deepen our investigation of collimated radio jets by examining large, unbiased samples of supermassive black holes in active galactic nuclei (AGN). Using the excellent spectroscopy of the (> million source) SDSS galaxy sample as a basis, we construct large samples of AGN that feature 1.4 GHz radio observations from the Very Large Array (VLA) FIRST survey. We use these samples to explore the relationship between average radio and optical line luminosities. We find that different scaling for the radio luminosity with accretion rate for LINERS compared to Seyferts and Quasars can explain the observed range of radio loudness. Lastly we explore another way of constructing an unbiased sample, starting with the same SDSS dataset, however this time not adding survey radio data, but adding serendipitously observed higher resolution, higher frequency VLA data, found by data-mining the entire (>120 000 observation) C-band (4.8 GHz) archive.

Date: Tuesday 6 September 2016, 14:00
Location: Agnietenkapel, Oudezijds Voorburgwal 231, Amsterdam