A Brief History of AGN

  title={A Brief History of AGN},
  author={Gregory Alan Shields},
Astronomers knew early in the twentieth century that some galaxies have emission-line nuclei. However, even the systematic study by Seyfert (1943) was not enough to launch active galactic nuclei (AGN) as a major topic of astronomy. The advances in radio astronomy in the 1950s revealed a new universe of energetic phenomena, and inevitably led to the discovery of quasars. These discoveries demanded the attention of observers and theorists, and AGN have been a subject of intense effort ever since… 
Evolution of cold gas in active galaxies.
Atomic hydrogen, hereafter referred to as HI, plays a crucial role in the evolution of galaxies and their central super-massive black-holes, fueling the formation of stars and feeding of active
Active Galactic Nuclei Influence the Genesis of Galaxies
Most or all spiral and elliptical galaxies were formed by quasars with supermassive black holes. The genesis of such galaxies occurred when the universe was young, approximately 5 billion years ago.
Active Galactic Nuclei and Pulsars
With the discovery of radio emission of extraterrestrial origin, it had opened a new and broader window in the electromagnetic spectrum to observe the sky. Two of the common sources of radio
The 3CR Chandra Snapshot Survey: Extragalactic Radio Sources with Redshifts between 1 and 1.5
The aim of this paper is to present an analysis of newly acquired X-ray observations of 16 extragalactic radio sources listed in the Third Cambridge Revised (3CR) catalog and not previously observed
Low-rate accretion onto isolated stellar-mass black holes
Magnetic field behaviour in a spherically-symmetric accretion flow for parameters typical of single black holes in the Galaxy is discussed. It is shown that in the majority of the Galaxy volume,
Radio observations confirm young stellar populations in local analogues to z ~5 Lyman break galaxies
We present radio observations at 1.5 GHz of 32 local objects selected to reproduce the physical properties of z .5 star-forming galaxies. We also report non-detections of five such sources in the
Antigravity—Its Manifestations and Origin
Dark energy has been introduced in order to explain the observed acceleration of the expansion of our Universe. It seems to be distributed almost uniformly and it has an essential influence on the
Astrophysics in 1999
The year 1999 saw the arrival of a star with three planets, a universe with three parameters, and a solar corona that could be heated at least three ways. In addition, there were at least three
Gravitational lensing signature of matter distribution around Schwarzschild black hole
In this work, we focus on the situation where a significant amount of matter could be located close to the event horizon of the central black hole and how it affects the gravitational lensing signal.
Russell Lecture: Dark Star Formation and Cooling Instability
Optically thin cooling gas at most temperatures above 30 K will make condensations by pressure, pushing material into cool, dense regions. This works without gravity. Cooling condensations will


Modern cosmology in retrospect
Preface Part I. The General Framework: 1. Cosmology, a peculiar science B. Bertoti 2. The early years J. D. North Part II. Riddles of and Clues to Cosmology: 3. Olbers' paradox in recent times E.
Active Galactic Nuclei a
Our current knowledge of active galactic nuclei is reviewed. The importance of observational data taken over a wide range of frequencies, from radio and infrared through optical and ultraviolet to
Astrophysics of Gaseous Nebulae and Active Galactic Nuclei
Preface Preface to First Edition General Introduction Photoionization Equilibrium Thermal Equilibrium Calculation of Emitted Spectrum Comparison of Theory with Observations Internal Dynamics of
The luminosity-volume test for a complete sample of quasi-stellar objects which consists of all those brighter than prescribed limiting radio and optical flux densities is investigated. The best
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Abstract : Contents include: Gravitational collapse; Properties of massive objects; Relativistic astrophysics; Massive stars, relativistic polytropes, and gravitational radiation; Massive stars in