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 Positron Distribution in the Inner Galactic Ridge written by and published by . This book was released on 1997 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: OSSE was used to measure the longitude and latitude distribution of positron annihilation in the inner galactic ridge using differential measurements relative to intensities at latitudes of plus or minus 10 degrees. An improved understanding of the 50 keV to 10 MeV continua has recently permitted accurate determinations of the positronium continuum flux intensities; this provides an - 5 times greater signal than was available in previous analyses which used only the 511 keV annihilation line. Within the statistical precision of the measurements, the line and positronium continuum components show indistinguishable distributions in both latitude and longitude. A differential measurement of their latitude distributions near the center indicates a narrow Gaussian ridge of -4.4 degrees FWHM. The longitude distribution of the ridge intensity differs from other known galactic ridge radiation distributions in that it shows a narrowly peaked maximum around the center. It can be characterized by an -12 degrees FWHM Gaussian central bulge plus a broad disk-like component. The only physical model based on plausibly associated galactic ridge distributions which can fit the observations well in longitude is the predicted galactic nova spheroid distribution, but scaled down by -2/3 from the latitude-integrated model bulge longitude width. The best fit has no additional discrete source or broad-disk components, although small contributions are permitted by the data. Novae are thought to be progenitors of Type I supernovae, probable sources of positrons in the galaxy, so this correlation suggests that Type I supernovae are the primary source of the positrons producing the observed galactic ridge annihilation radiation.
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 Energy Research Abstracts written by and published by . This book was released on 1985 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1985 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Electron Pairs in Astrophysics written by Michael L. Burns and published by American Institute of Physics. This book was released on 1983 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1985 with total page 1652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1984 Part 1 written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 947 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of Los Alamos Research written by Los Alamos National Laboratory and published by . This book was released on 1984 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positrons in Solids written by P. Hautojärvi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: In condensed matter initially fast positrons annihilate after having reached equi librium with the surroundings. The interaction of positrons with matter is governed by the laws of ordinary quantum mechanics. Field theory and antiparticle properties enter only in the annihilation process leading to the emergence of energetic photons. The monitoring of annihilation radiation by nuclear spectroscopic methods provides valuable information on the electron-positron system which can directly be related to the electronic structure of the medium. Since the positron is a positive electron its behavior in matter is especially interesting to solid-state and atomic physi cists. The small mass quarantees that the positron is really a quantum mechanical particle and completely different from any other particles and atoms. Positron physics started about 25 years ago but discoveries of new features in its interac tion with matter have maintained continuous interest and increasing activity in the field. Nowadays it is becoming part of the "stock-in-trade" of experimental physics.
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1983 with total page 1144 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 Current Topics In Astrofundamental Physics Proceedings Of The 2nd Course In The International School Of Astrophysics D Chalonge written by Normalized Sanchez and published by World Scientific. This book was released on 1993-08-27 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an updated understanding of the progress and current problems in the interplay between fundamental physics, astrophysics and cosmology.
Download or read book Positron Annihilation written by A.T. Steward and published by Elsevier. This book was released on 2012-12-02 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron Annihilation focuses on the process of positron annihilation in different environments. Partitioned into two parts with 42 chapters, the book contains the contributions of authors who have done research on the annihilation of positrons, which brought about valuable information on the properties of matter. The first part of the book deals with lengthy review articles, including a survey of the physics of positron annihilation; positron annihilation in metals and the theory involved in the process; and positron annihilation in alkali halides and ionic crystals. Positronium formation and interaction in gases, molecular substances, and ionic crystals are also given attention. Gaseous positronics and positron annihilation in condensed gases and liquids are also discussed. The second part of the book focuses on developments on positron annihilation and the direction of research on this field. The studies concentrate on positron annihilation in various crystals, metals, mercury, liquefied gases, helium, and metal oxides. Numerical representations and analyses are presented to support the processes involved. The book can best serve the interest of those who want to explore further the annihilation of positrons.
Download or read book Literature 1985 Part 1 written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-12-11 with total page 1157 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 39 records literature published in 1985 and received before August 15, 1985. 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 organiza tions, observatories, and publishers which provide us with complimentary copies of their publications. On account of the introduction of an object index the scope of index information will be considerably enlarged beginning with this volume. In connection with the subject index an additional source to satisfy the needs of retrieval is opened up. 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, Ms. Sylvia Matyssek. Ms. Karin Burkhardt, Ms. Susanne Schlotelburg, and Mr. Stefan Wagner supported our task by careful proofreading. It is a pleasure to thank them all for their encouragement. Heidelberg, September 1985 The Editors Contents Introduction . . . . . . . . . . . .
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1978 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Resolution Gamma ray Cosmology written by David Cline and published by . This book was released on 1989 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
