AN INVESTIGATION AND ANALYSIS OF RATIO ' WAVES OF EXTRATERRESTRIAL ORIGIN DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By HSIEN-CHING KO, B.S., M.S. The Ohio State University 1 9 # Approved by: _ Adviser Department of Electrical Engineering ACKNOWLEDGEMENTS The research presented in this dissertation was done at the Radio Observatory of The Ohio State University under the supervision of Professor John D* Kraus who originated the radio astronory project, designed the radio telescope and guided the research. The author wishes to express his sincere appreciation to Professor Kraus, his adviser, for his helpful guidance, discussion and review of the manuscript. For three years he has continuously- provided the author with every assistance possible in order that the present investigation could be successfully completed. Dr. Kraus has contributed many valuable new ideas throughout the investigation* It is a pleasure to acknowledge the work of Mr. Dorm Van Stoutenburg in connection with the improvement and maintenance of the equipment. Thanks are also due many others who participated in the construction of the radio telescope. In addition, rry thanks go to Miss Pi-Yu Chang and Miss Justine Wilson for their assistance in the preparation of the manuscript, and to Mr. Charles E. Machovec of the Physics Library for his cooperation in using the reference materials• The radio astronony project is supported ty grants from the Development Fund, the Lovejqy Memorial Fund, and the fund for the basic research of The Ohio State University and also ty a grant from the National Science Foundation* TABUS OF CONTENTS CHAPTER I INTRODUCTION 1.1 Historical 1.2 Radio Astronomy at The Ohio State University 1.3 Statement of the Problems II APPARATUS AND THEORETICAL CONSIDERATIONS 2.1 Quantitative Measurements and Units 2.2 Limit of Detection 2.3* Attenuation between Antennaand Receiver 2.U Celestial and Antenna Coordinates in Radio Astronomy 2.^ The Antenna Relationship 2.6 The Ohio State University Radio Telescope III OBSERVATIONAL PROCEDURE IV LOCALIZED SOURCES OF EXTRATERRESTRIAL RADIO RADIATION U.l Introduction i|. 2 Detection of Radio Sources 14.3 Distribution of Radio Sources l+.U The Radio Magnitude, Color and Spectrum Index U.5 Indentification of Radio Sources V COSMIC RADIO BACKGROUND RADIATION 5.1 Introduction 5.2 Construction of a Radio Map of the Sky 5.3 Discussion of the Distribution of Cosmic Radio Background Radiation VI A RADIO MODEL OF THE GALAXY 6.1 Introduction 6.2 Galactic Structure 6 . 3 The Center of the Galaxy 6.U Construction of a Radio Model of the Galaxy 6.5 Comparison with the Andromeda Nebula VII SUMMARY BIBLIOGRAPHY CHAPTER I INTRODUCTION 1.1 Historical The young science of radio astronomy is coining of age. Using radio antennas and receivers instead of the conventional optical lenses and eyepieces it has opened a new window on the universe. Although Sir Oliver Lodge speculated on the possibility of de­ tecting solar emission at the beginning of this century, the fundamental discovery in radio astronomy was made in 1932 when Karl Jansky (37) of the Bell Telephone Laboratory found the first evidence for the existence of radio radiation of extraterrestrial origin. These accidental obser­ vations by Jansky opened up a new era in astronomical investigations, since our knowledge of the universe had previously been gained only by observations of the radiation in a narrow range of optical wave­ lengths. To these light waves from the stars and galaxies for the astronomer's telescope there have been added radio waves for the radio astronomer's antennas and receivers. These radio waves can penetrate the earth's atmosphere and ionosphere over a wide range of frequencies. As seen in Figure 1, the optical window covers the visual and near -k -3 visual wavelengths from about 3 x 10 cm to about 10 cm (about five octaves), while the radio window extends from about 1 cm to at least 20 m (about 11 octaves) which is restricted by the ionosphere on the long wave side and by molecular absorption bands on the other side. Between 1937 and 19U8* Reber (66, 67) studied the cosmic radio radiation with apparatus especially designed for the purpose and mapped the distribution of the galactic radio radiation brightness with some Ui ' »- <t Lj ffi y - RAY -*+*- X-RAY OC INFRA-RED RADIO i O CO _l — > ID > I £ I o OZONE o MOLECULAR IONOSPHERE ABSORPTION ABSORPTION RADIO REFLECTION I I < o I- Q_ O I J__ 1 I -10 -8 -6 - a -2 10 10 10 10 10 I 10 10 10 WAVELENGTH IN cm Fig. 1. The electromagnetic spectrum showing the regions of transparency of the earth's atmosphere. detail. He also attempted to detect radio radiation from the sun and extragalactic nebulae without success. In 19U2 and 19k3 Southworth (?U) succeeded in detecting radio radiation from the sun at wavelengths from 1 to 10 cm. Appleton and Hey ( 1 ) investigated observations recorded during the second world war with radar equipment and found a significant relationship between intense solar radio outbursts, sunspots and flares. But the emergence of radio techniques as a powerful tool in astronomical investigation has only oceured during the past ten years. During the work of Appleton and his colleagues on the nature of the ionosphere, they observed the short period sporadic reflection of radio waves which has since achieved such importance in the study of meteors. This has opened the field of "Meteor Astronomy". The next major discovery was that of the localized radio sources or so called "radio stars". In the flilky Way radio survey made by Hey, Parson and Phillips (36) at 6i| Mc/s, they noticed that the radiation from the direction of Gygnus showed fluctuations in intensity and suggested that at least part of the galactic noise was due to a very intense discrete radio source. Afterwards a detailed study of this region by Bolton and Stanley (ID), using, a Lloyd-mirror interference '1 technique, confirmed the existence of a discrete radio source less than 8 minutes of arc in diameter in the constellation of Cygnus. Ryle and Smith (69) found another intense discrete source in the constellation of Cassiopeia, using the radio version of Michelson's stellar inter­ ferometer. At .the present time more than several hundred radio sources have been found and the number increases as more sensitive h radio telescopes are brought into use. Some radio sources have been identified by Baade and Minkowski (5>6), using the 200 inch Mt. Palomar telescope, with interesting optical objects such as colliding galaxies, peculiar nebulosities and remnants of supernovae. In 195?1, Hanbury Brown and Hazard (28) succeeded in detecting radio emission from extra- galactic nebulae such as the Andromeda Nebula and from an aggregate of such nebulae. The distribution of radio brightness across the Andro­ meda Nebula has recently been studied by Professor Kraus with the narrow beam of The Ohio State University radio telescope. Radio radiation from the supergalaxy was detected by Professor Kraus and Ko (1+6) in 1953* The possibility of radio astronomical spectroscopy was first con­ sidered by van de Hulst (82) in 191+1+ but it was not until 19$1 that the 21 cm hydrogen line was detected by Ewen and Purcell (22) at Harvard. This result was confirmed only a few weeks later by Muller and Oort (5>8) at Leiden and a little later by Christiansen and Hindman in Australia (19). This achievement has provided a new way to study the spiral structure of our own galaxy. The contribution of radio astronomy to the knowledge of our galaxy may be greater than to the knowledge of the sun and meteors, van de Hulst, Muller, and Oort (83) have recently publish­ ed charts showing the structure of the spiral arms using their 21 cm observations. Investigations at centimeter wave-lengths have recently been start­ ed at the Naval Research Laboratory (Washington, D.C.) and many ionized hydrogen nebulae and H II regions have been detected by Haddock, Mayer and Sloanaker (26) at a wave-length of 9.1+ cm and by Hagen, McClain and Hepburn (27) at 21 cm. $ 1,2 Radio Astronomy at The Ohio State University A radio astronomy project at The Ohio State University was initiat­ ed in 1951 by Professor John D. Kraus who designed the radio telescope and has directed the program. In the summer of 1952, a radio telescope consisting of an array of 2h helical antennas was completed and put into use ibr the preliminary survey of the galactic radio radiation at 250 Mc/s, In the winter of 1952 the antenna size was enlarged to I4.8 helices and the galactic and localized source observations were begun. In this survey 207 localized sources were detected and a radio map of a part of the sky was obtained. Radio radiation from the supergalaxy was also detected. In the summer of 1953, the radio telescope was again increased in size to 96 helices and the receiving system was improved considerably. With this new equipment, the detailed structure of the cosmic radio radiation was studied and many localized and extended sources were detected. Many articles have been published during the past three years (3 8 — 53) and in addition there have been 6 master's theses and two Ph.D. dissertations including the present one completed on this project. 6 1.3 Statement of the problem Several radio surveys have been made over various parts of the celestial sphere between frequencies of 9.5 and J4.8O Mc/s by many observers.