Download or read book Positron Annihilation in the Galactic Center written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two separate observations of the .gamma.-ray spectrum originating from the Galactic Center were made by HEAO-3 in the fall of 1979 and in the spring of 1980. The 2.gamma. 511 KeV annihilation line flux decreased by a factor of three over the corresponding six month period, whereas the excess .gamma.-ray continuum below the 511 KeV line, often interpreted as 3.gamma. decay of orthopositronium, barely changed. This apparent discrepancy in the temporal behavior makes it difficult to associate the bulk of the excess continuum with the 3.gamma. decay of positronium. We will show that Compton scattering of the line and high energy radiation provides a natural explanation for the surprisingly small change seen in the excess continuum. 11 refs., 2 figs.
Download or read book Positrons from Supernova and the Origin of the Galactic center Positron annihilation Radiation written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The emission of positrons from supernova ejecta is dicussed in terms of the galactic-center annihilation radiation. The positrons from the radioactive sequences 56Ni.-->.56Co.-->.56Fe are the most numerous source from supernova. Only type I supernova will allow a significant fraction to escape the expanding ejecta. For a neutron star model of a type I SN a fraction 4 x 10−3 of the escaped positron is enough to create the observed several year fluctuation of the annihilation radiation. The likelihood of this model is discussed in terms of other astrophysical evidence as well as the type I SN light curve.
Download or read book Observations of Galactic Positron Annihilation Radiation written by Michael S. Briggs and published by . This book was released on 1991 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Center of the Galaxy written by Mark Morris and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of the Galactic nucleus and its surroundings is necessarily a modem endeavor, for traditional observations made at visual wavelengths have not even begun to penetrate the veil of -30 magnitudes of visual extinction that intercedes. On the other hand, infrared, and especially radio observers find a relatively unobstructed view of the central portion of the Galaxy, so the study of this arena has proceeded apace with the development of these branches of astronomy. Thus, it is no accident that the first IAU sponsored conference to be held on the Galactic center is timed to coincide with the initiation, or the immediate aftennath, of major technical developments at long wavelengths, including infrared array detectors, millimeter-wavelength aperture synthesis, and self-calibration and refmed deconvolution algorithms in aperture synthesis radio astronomy. The center of the Galaxy is also accessible to X and gamma-ray observers, and progress at high energies has been steady, especially as imaging capabilities are being realized at X-ray wavelengths. However, one might expect that the revolution in the high energy domain is still ahead of us, as instruments with larger collecting areas and improved spatial resolution are now being developed. The youth of this subject is evidenced by the relatively small number of meetings that have been devoted to it.
Download or read book The Galactic Center written by Guenter R. Riegler and published by American Institute of Physics. This book was released on 1982 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Energy Astrophysics written by James Matthews and published by World Scientific. This book was released on 1994 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of comprehensive reviews on astrophysics at the highest energies. It puts together, for the first time, discussions of astrophysics from MeV to EeV energies and beyond. Observations at these energies reveal nuclear and particle physics throughout our galaxy as well as in the most extreme environments in the entire cosmos. These reports range from the recent spectacular results from the Compton Gamma Ray Observatory, including the latest information on enigmatic gamma ray bursts, to cosmic rays at the highest energies ever observed by man.
Download or read book The Galactic Center written by Donald C. Backer and published by American Institute of Physics. This book was released on 1987 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Electron Gas Scattering Proceedings Of The 3rd International Workshop written by Walter E Kauppila and published by World Scientific. This book was released on 1986-04-01 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: This workshop discusses the current state and future directions of research in positron — gas scattering, particularly in the relationship between positron and electron scattering by the same atoms and molecules. The possible applications of positron — gas scattering to astrophysical phenomena have also been discussed.
Download or read book Positron Annihilation written by Zsolt Kajcsos and published by . This book was released on 1992 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt: The volumes present over 400 reviewed papers on the present state of the art and future prospects in the wide field of research involving positrons. The foreword by Edward Teller and the summaries by Jean-Charles Abbe (Chemistry) and Alfred Seeger (Physics) demonstrate how the field is seen from outside and from inside.
Download or read book Dark Matter Annihilation in The Galactic Center As Seen by the Fermi Gamma Ray Space Telescope written by and published by . This book was released on 2010 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OSSE Observations of Galactic 511 KeV Annihilation Radiation written by and published by . This book was released on 1991 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma-Ray Observatory has performed several observations of the Galactic plane and Galactic center region to measure the distribution of Galactic 511 keV positron annihilation radiation. Preliminary analysis of data collected during the observation of the Galactic center region over the period July 13[24, 1991, indicates the presence of a 511 keV line and positronium continuum superimposed on a power-law continuum.
Download or read book Positron Annihilation in Chemistry written by Ole E. Mogensen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only critical discussion available on the chemistry of the two "strange" light particles, the positron and positronium, with much space devoted to the excess electron. Positron annihilation allows the investigation of many unusual phenomena in the reaction kinetics of the positron, positronium, and excess electron, and in radiation chemistry and physics, while also providing important information on defects in solids.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gamma ray Astronomy written by P. V. Ramana Murthy and published by Cambridge University Press. This book was released on 1993-04 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent launch of NASA's Gamma-Ray Observatory will increase interest in gamma-ray astronomy. This is a fully up-dated new edition of the authors' earlier volume published in 1986 and covers both the background science and the current state-of-the-art in this field. The emphasis is on the astronomy and astrophysics of known sources of cosmic gamma-rays outside the solar system. The authors discuss the mechanisms for the production and absorption of gamma-rays. The gamma-ray line astronomy of the interstellar medium, galactic centre, and various discrete sources is then considered. Gamma-ray bursts are treated in considerable detail in chapter three, and the final two chapters describe medium energy and ultra-high energy gamma-rays. Relevant data from supernova SN1987A is also included in this edition. The book includes comprehensive references to the primary literature, together with many figures and tables. The concentration on phenomenology makes this book a fine introduction to gamma-ray astronomy.
Download or read book Literature 1989 Part 1 written by Astronomisches Rechen-Institut and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1433 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: "Astronomy and Astrophysics Abstracts has appeared in semi-annual volumes since 1969 and it has already become one of the fundemental publications in the fields of astronomy, astrophysics and neighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. ...The abstracts are classified under more than a hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world." Space Science Review# "Dividing the whole field plus related subjects into 108 categories, each work is numbered and most are accompanied by brief abstracts. Fairly comprehensive cross-referencing links relevant papers to more than one category, and exhaustive author and subject indices are to be found at the back, making the catalogues easy to use. The series appears to be so complete in its coverage and always less than a year out of date that I shall certainly have to make a little more space on those shelves for future volumes." The Observatory Magazine#
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1983 Part 1 written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 825 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy and Astrophysics Abstracts aims to present a comprehensive documen tation of the literature concerning all aspects of astronomy, astrophysics, and their border fields. It is devoted to the recording, summarizing, and indexing of the relevant publications throughout the world. Astronomy and Astrophysics Abstracts is prepared by a special department of the Astronomisches Rechen-Institut under the auspices of the International Astronomical Union. Volume 33 records literature published in 1983 and received before August 1, 1983. Some older documents which we received late and which are not surveyed in earlier volumes are included too. We acknowledge with thanks contributions of our colleagues all over the world. We also express our gratitude to all organizations, observatories, and publishers which provide us with complimentary copies of their publications. Starting with Volume 33, all the recording, correction, and data processing work was done by means of computers. The recording was done by our technical staff members Ms. Helga Ballmann, Ms. Mona El-Choura, Ms. Monika Kohl, and Ms. Sylvia Matyssek. Mr. Martin Schlotelburg and Mr. Ulrich Uberall supported our task by careful proofreading. It is a pleasure to thank them all for their encouragement. Heidelberg, September 1983 The Editors Contents Introduction . . . . . . . . . . . . 1 Concordance Relation: ICSU-AB-AAA 3 Abbreviations 10 Periodicals, Proceedings, Books, Activities 001 Periodicals . . . . . . . . . . . 15 002 Bibliographical Publications, Documentation, Catalogues, Atlases 47 003 Books ...... . 51 004 History of Astronomy 58 005 Biography . . 64 006 Personal Notes 65 007 Obituaries . . .
