The Society publishes reports on all of its lectures, some of its visits, selected members papers and suggested reading material in its bookshelf.  These can all be found in date order below.

The Society also published a monthly bulletin, the archive for these can be found here.


 

Date: Wednesday, 18 Sep 2013
Jon Hoyle
Senior Archaeology Officer for Gloucestershire County Council
Download Report: 2013-09-18-lidar.pdf
Date: Wednesday, 12 Jun 2013
Professor David Phillips
Emeritus professor of chemistry, Imperial College, London
Download Report: 2013-06-12-a-little-light-relief.pdf
Date: Wednesday, 8 May 2013
Professor Michael Danson
University of Bath
Download Report: 2013-05-08-extremophiles.pdf
Date: Wednesday, 10 Apr 2013
Professor Mark Casson
Director of Reading University’s Centre for Institutional Planning
Download Report: 2013-04-10-railway-network.pdf
Visit Date: Thursday, 14 Mar 2013
Download Report: 2012-03-14-visit-report-npl.pdf
Date: Wednesday, 13 Mar 2013
Professor Jonathan Reid
Bristol University Chemistry Department
Download Report: 2013-03-13-aerosols.pdf
Date: Wednesday, 13 Feb 2013
Mr Chris Warrick
UKAEA Culham Centre for Fusion energy
Download Report: 2013-02-13-nuclear-fusion.pdf
Date: Wednesday, 9 Jan 2013
Professor Alison Smith
Cambridge University
Download Report: 2013-01-09-algal-biofuels.pdf

Professor McHardy explained the background and current understanding of active galaxies or active galactic nuclei (AGN) since the first explanation of their existence in the mid-fifties.  The development of new telescopic techniques, from optical to X-ray, infra-red etc and particularly the Hubble space telescope has led to a greater understanding of AGN’s and the mechanisms which power them.

Active galaxies emit more energy than would be expected from the sum of emissions from each of the stars found in the galaxy.  The most common explanation assumes that they are powered by accretion onto massive black holes (between 100 and 1000 times the mass of our sun) at the centre of the AGN.  This in turn releases large amounts of gravitational energy which is emitted in the infra-red, UV, infra-red and X-ray regions of the electromagnet spectrum.

Professor McHardy described several types of active galaxies including Seyferts, quasars and blazars but many scientists believe that, even though these types look very different to us, they are really all the same thing viewed from different directions.  Photographs show exceptionally bright centres sometimes accompanied by bright jets of hot plasma.

Seyfert galaxies are much closer to us than quasars or blazars and were first observed in the 1940’s using optical telescopes.  They are characterized by having small, bright nuclei (optical) and strong emission lines in their optical spectrum. Quasars are active galaxies which are the farthest away from us – as far as 12 billion light years. Blazars are very bright in the radio band, which results from looking directly down a jet which is emitting in synchrotron radiation.

Professor McHardy explained that the on-going study of AGNs is providing greater insights into how the universe was formed and how it functions.

Date: Wednesday, 14 Nov 2012
Professor Ian McHardy
Southampton University
Download Report: 2012-11-14-active-galaxies.pdf
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