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 Gamma Ray Emission from the Inner Galactic Ridge written by and published by . This book was released on 1997 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: An improved measurement of the composite 0.05 to 10 MeV gamma-ray spectra as a function of longitude from the inner galactic ridge has been made using the Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma Ray Observatory. The continuum appears to be a composite of 3 independent components. A strong positron annihilation contribution is observed toward the center with an intensity which decreases rapidly with distance from the center (FWHM ~12 degrees). A second contribution is a soft low-energy component with a broad longitude distribution and spectra well-approximated by an exponentially absorbed power-law. The third is a hard component with an approximately longitude-independent power-law spectral shape (photon index ~-1.75) from ~200 keV to 10 MeV. When positron annihilation radiation is subtracted, this is the dominant feature above 0.2 MeV at all observed longitudes. For an assumed 5 degrees FWHM latitude width at the center, the spectrum and intensity of this component agrees with extrapolations of measurements above 30 MeV using a cosmic-ray interaction model. When account is taken of bright source contributions, both these continuum components' distributions are consistent with the galactic CO longitude distribution along the plane. These results, in conjunction with previous measurements, provide new information for determining the galactic cosmic-ray electron spectrum down to the MeV region.
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 OSSE Observations of Positron Annihilation in the Galactic Plane written by and published by . This book was released on 1996 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: OSSE has measured the galactic longitude distribution of both the 511 keV annihilation line radiation and the three-photon positronium continuum within ~40 degrees of the center. They have similar shapes, with a composite longitude distribution well represented by an ~11 degrees FWHM Gaussian central bulge together with a possible broad disk component comprising as much as 15% of the integral flux between 40 degrees and 320 degrees longitude. Contributions from one or more discrete source(s) at or near the center with total annihilation radiation (line plus continuum) intensities of up to ~4 x 10(exp -4) photons cu cm sec(exp -1) (2 sigma upper limit) are compatible with the observed distribution. The best estimate of the positronium fraction is 0.97 plus or minus 0.03. No evidence for variation in the positronium fraction is observed.
Download or read book Reports on Astronomy written by Jacqueline Bergeron and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 603 pages. Available in PDF, EPUB and Kindle. Book excerpt: IAU Transactions are published as a volume corresponding to each General Assembly. Volume A is produced prior to the Assembly and contains Reports on Astronomy, prepared by each Commission President. The intention is to summarize the astronomical results that have affected the work of the Commission since the production of the previous Reports up to a time which is about one year prior to the General Assembly. Volume B is produced after the Assembly and contains accounts of Commission Meetings which were held, together with other material. The reports included in the present volume range from outline summaries to lengthy compilations and references. Most reports are in English.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2730 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transactions of the International Astronomical Union written by International Astronomical Union and published by . This book was released on 1994 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Canadian Journal of Physics written by and published by . This book was released on 2008 with total page 938 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 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1986 Part 1 written by Prof. Dr. Roland Wielen and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Energy Cosmic Rays written by Todor Stanev and published by Springer Science & Business Media. This book was released on 2010-03-10 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models
Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 1216 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 1984 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Particle Detection and Imaging written by Claus Grupen and published by Springer Science & Business Media. This book was released on 2012-01-08 with total page 1251 pages. Available in PDF, EPUB and Kindle. Book excerpt: The handbook centers on detection techniques in the field of particle physics, medical imaging and related subjects. It is structured into three parts. The first one is dealing with basic ideas of particle detectors, followed by applications of these devices in high energy physics and other fields. In the last part the large field of medical imaging using similar detection techniques is described. The different chapters of the book are written by world experts in their field. Clear instructions on the detection techniques and principles in terms of relevant operation parameters for scientists and graduate students are given.Detailed tables and diagrams will make this a very useful handbook for the application of these techniques in many different fields like physics, medicine, biology and other areas of natural science.
