Introduction to experimental techniques of high-energy astrophysics
Measurements of cosmic rays and high energy extraterrestrial particles
Oegelman, H.↗
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The High Energy Astronomical Observatory.
The High Energy Astronomical Observatory (HEAO) is an earth satellite platform designed specifically around the very large and heavy instruments now required to make a significant advance in high-energy astrophysics. This new field of astronomy includes X-ray, gamma-ray, and cosmic-ray studies. The state of knowledge in high-energy astrophysics is discussed, giving attention to X rays, gamma rays, the diffuse component, emission mechanisms, and particle astrophysics. The observational objectives of the HEAO are considered together with the HEAO configuration and the experiments under study for the first HEAO, the HEAO-B, and the HEAO-C. HEAO-A is to be placed in orbit in 1975.-
Peterson, L. E.↗
High energy particles and quanta in astrophysics
The various subdisciplines of high-energy astrophysics are surveyed in a series of articles which attempt to give an overall view of the subject as a whole by emphasizing the basic physics common to all fields in which high-energy particles and quanta play a role. Successive chapters cover cosmic ray experimental observations, the abundances of nuclei in the cosmic radiation, cosmic electrons, solar modulation, solar particles (observation, relationship to the sun acceleration, interplanetary medium), radio astronomy, galactic X-ray sources, the cosmic X-ray background, and gamma ray astronomy. Individual items are announced in this issue.
Mcdonald, F. B.↗
Research with the space shuttle
The space-research capabilities of the Space Shuttle System are assessed in a review of its systems and instrumentation, visualizing the beginning of a new era for science in space with the start of shuttle operations expected in 1979. The Shuttle parameters are listed and the Large Space Telescope and the Plasma Physics and Environmental Perturbation Laboratory of the Shuttle are described. The Shuttle-based research in astronomy, atmospheric and space physics, high-energy astrophysics, and relativity is discussed. The versatile capabilities of the Shuttle as a plasma laboratory, a source of perturbation, and observing platform, and a particle precipitator are noted.
Naugle, J. E.↗
Search for brief celestial X-ray bursts
The occurrence of intense bursts of 0.1- to 1.5-MeV photons from space has been confirmed with observations from IMP-6. This is the first positive result of an extensive data comparison, in which a search was made of OGO and IMP records for time coincidences between brief X- or gamma-ray increases and a variety of other transient phenomena. The IMP-6 measurements provided the first differential energy spectra of these events, the shapes of which indicate that photons predominantly in the gamma-ray domain are released into space. Whether these bursts originate in distant supernovae or in some new class of relatively nearby gamma-ray flare stars, they reveal a process which is new to high-energy astrophysics, not only because of the unusual spectrum, but also because of the brief time scales involved and because of the intense fluxes observed.
Cline, T. L.↗
Europe gets aboard the Shuttle
A series of experiments directed by NASA for the European Space Agency's Spacelab are planned for early 1983. Spacelab 1 is scheduled to carry equipment for upper atmosphere research and for experiments in plasma and solar physics, medicine, and thermodynamics. Spacelab 2 will provide equipment for research in astronomy, high-energy physics, astrophysics, and solar physics. Spacelab 3 will be equipped to study materials processing in space, biological tests, and cloud physics. Spacelab is modular and reusable, with the planned life equal to 50 missions. The Space Shuttle will carry a Spacelab with scientific equipment of up to 8800 kg into orbits ranging in altitude from 160 to 1100 km and transmitting data at up to 50 Mb/s. The cost of launching a Shuttle/Spacelab mission is estimated at $28 million.
Moye, J. E.↗
Gamma-ray Astrophysics: a New Look at the Universe
Gamma-ray astronomy which includes the spectral region from above approximately 100 keV to greater than or equal to 1000 GeV permits investigation of the most energetic photons originating in our galaxy and beyond and provides the most direct means of studying the largest transfers of energy occurring in astrophysical processes. Of all the electromagnetic spectrum, high-energy gamma-ray astronomy measures most directly the presence and dynamic effects of the energetic charged cosmic ray particles, element synthesis, and particle acceleration. Further, gamma rays suffer negligible absorption or scatterings as they travel in straight paths; hence, they may survive billions of years and still reveal their source. The high energy processes in stellar objects (including our Sun), the dynamics of the cosmic-ray gas, the formation of clouds and nebulae, galactic evolution and even certain aspects of cosmology and the origin of the universe may be explored by gamma-ray observations.
Trombka, J. I.↗
Next-Generation Hard X-ray Missions: SuperHERO and HEROIX
High-energy X-ray observations have transformed our understanding of astrophysical systems where non-thermal processes dominate, from shock-accelerated particles in supernova remnants to relativistic jets and hot coronae in active galactic nuclei. NuSTAR’s pioneering focusing images of the hard X-ray sky have demonstrated the immense scientific potential of this band, while also highlighting how limited angular resolution constrains our ability to fully characterize complex physical processes in faint extended sources and resolving faint sources in crowded sky regions. In this presentation, I will discuss a pathway to overcome these challenges through NASA Marshall Space Flight Center’s replicated NiCo full-shell X-ray mirror technology. Specifically, I will discuss the SuperHERO hard X-ray telescope to achieve better than 10-arcsecond half-power diameter (HPD) angular resolution on a balloon flight observing the Crab Nebula, and the High EneRgy Observatory for Imaging X-rays (HEROIX) Medium-Class Mission concept to achieve an integrated effective area of 570 cm2 at 30 keV with 5 arcsec HPD angular resolution.
AGN↗
High EneRgy Observatory for Imaging X-rays (HEROIX) Mission Concept
The High EneRgy Observatory for Imaging X-rays (HEROIX) is a next-generation broadband X-ray space telescope concept under development as a Medium-Class Explorer mission. Building on more than three decades of replicated NiCo shell technology at NASA’s Marshall Space Flight Center, HEROIX will deliver 5 arcsecond half-power-diameter imaging resolution in the hard X-ray band. The observatory will incorporate four co-aligned telescopes with advanced multilayer coatings, extending the bandpass into the hard X-ray regime and providing an integrated effective area of 380 cm² at 30 keV. A suite of focal plane detectors will enable imaging capability throughout its 1–80 keV bandpass. This combination of angular resolution and high-energy coverage will open new windows into non-thermal processes in extreme astrophysical environments. HEROIXwill deliver transformative science, advancing the astrophysics community’s understanding of supernova physics, the X-ray binary population of the Galactic Center, accretion-driven galaxy evolution, and the origin of the Cosmic X-ray Background.
Nick Thomas↗
Role of magnetic fields in physics and astrophysics; Proceedings of the Conference, Copenhagen, Denmark, June 5-7, 1974
The papers deal with the role of magnetism in astrophysics and the properties of matter in the presence of unusually large magnetic fields. Topics include a quantum-mechanical treatment of high-energy charged particles radiating in a homogeneous magnetic field, the solution and properties of the Dirac equation for magnetic fields of any strength up to 10 to the 13th power gauss, experimental difficulties encountered and overcome in generating megagauss fields, the effect of strong radiation damping for an ultrarelativistic charge in an external electromagnetic field, magnetic susceptibilities of nuclei and elementary particles, and Compton scattering in strong external electromagnetic fields. Other papers examine static uniform electric and magnetic polarizabilities of the vacuum in arbitrarily strong magnetic fields, quantum-mechanical processes in neutron stars, basic ideas of mean-field magnetohydrodynamics, helical MHD turbulence, relations between cosmic and laboratory plasma physics, and insights into the nature of magnetism provided by relativity and cosmology. Individual items are announced in this issue.
Canuto, V.↗
Infrared astronomy and high energy astrophysics
Observations of the diffuse far infrared flux from the galactic plane as well as far infrared measurements of the properties of dense molecular clouds, when combined with recent high-energy gamma ray measurements and radio observations of carbon monoxide, can yield new information about the total mass of molecular clouds, the large scale structure of the inner galaxy, and the density of cosmic rays. These observations are discussed.
Fazio, G. G.↗
Infrared astronomy and high energy astrophysics
Observations of the diffuse far-infrared flux from the galactic plane, as well as far-infrared measurements of the properties of dense molecular clouds, when combined with recent high-energy gamma-ray measurements and radio observations of carbon monoxide, yield information about the total mass of molecular clouds, the large-scale structure of the inner galaxy, and the density of cosmic rays.
Fazio, G. G.↗
Astrophysical gamma-ray production by inverse Compton interactions of relativistic electrons
The inverse Compton scattering of background photon gases by relativistic electrons is a good candidate for the production of high-energy gamma rays in the diffuse interstellar medium as well as in discrete sources. By discussing the special case of the scattering of the diffuse starlight in the interstellar medium by cosmic ray electrons, we demonstrate that previous derivations of the gamma ray source function for this process on the basis of the Thomson limit of the Klein-Nishina cross section lead to incorrect values for gamma-ray energies above 100 MeV. It is shown that the Thomson limit is not applicable for the calculation of gamma-ray source functions in astrophysical circumstances in which target photons with energies greater than 1 eV are scattered by relativistic electrons.
Schlickeiser, R.↗
What can X-rays tell us about SNR's
It is pointed out that X rays have been detected from about a dozen supernova remnants (SNRs) of the Galaxy. A reasonably current catalog of X-ray SNRs is given in a table. All the remnants are close, within 3 kpc of the sun (except for Tycho, which is probably twice that distance). The information of astrophysical significance which can be gained from X-ray observations of SNRs is discussed. General observational considerations are followed by a discussion of the Vela SNR as a typical case. Young SNRs are the ones most likely to yield information about the supernova process. Attention is also given to the second High-Energy Astronomical Observatory which is to provide much additional information concerning the SNRs.
Winkler, P. F., Jr.↗
Gamma-ray line emission above 8 MeV
The spectra of energetic nuclei within astrophysical sources may be determined by studying gamma-ray line emissions above 8 MeV. Excited states which can be produced by inelastic scattering, charge exchange, and spallation reactions in the abundant nuclear species were considered in order to identify nuclear lines which may contribute to the gamma spectrum. The cross sections for production of most high-energy states are sparsely measured. Those which were determined are comparable to the cross section for production of the 15.11 MeV level in C-12 with few exceptions. The branching ratios for gamma-ray and particle emission are, however, better known. Of those states considered, 44 measured branching ratios greater than 40% for emission of a gamma-ray with energy above 8 MeV. For twelve more states the branching ratios, although not yet determined, are expected to be small. The gamma-ray emission from other individual nuclear states is not likely to be as great as that that for the 15.11 MeV state in C-12.
Crannell, C. J.↗
High-energy radiations from space.
Survey of past, current, and planned U.S. high-energy astronomy observation (HEAO) experiments in space, and review of their significance. It is shown that astronomical observations from spacecraft during the first decade of space flight, though they be few and modest, have provided a wealth of new results that are most exciting, and that suggest that the next 20 or 30 years of space exploration may write a new chapter in the history of astrophysics and astronomy as important as the chapters initiated by Galileo or by the five-meter telescope on Mount Palomar. Special attention is given to the planned HEAO-A and HEAO-B experiment series.
Stuhlinger, E.↗
Gamma-ray astrophysics
The experimental development of gamma-ray astronomy and detectors for gamma-ray observations is reviewed together with recent results obtained by the SAS-2, COS-B, and other satellites. Diffuse gamma-ray emission from the galactic plane is discussed, various localized sources are examined, and the primary production processes for celestial gamma-rays are treated in relation to the difficulty involved in detecting this radiation. Several different types of gamma-ray detectors are described in detail, and the production of high-energy gamma-rays by cosmic-ray interactions with interstellar matter is investigated. Observations of gamma-rays from the Crab Nebula and pulsar, the Vela pulsar, Cen A, and other point or localized sources are summarized with observations of nuclear gamma-ray lines during solar flares. Possible interpretations are considered for the diffuse gamma-radiation detected in regions away from the galactic plane.
Fichtel, C. E.↗
A mechanism for the production of pulsar radio radiation
Recent theoretical studies have suggested that avalanches of electron-positron pairs are produced by spark discharges near the magnetic poles of pulsars. This pair production mechanism may result in a double-peaked particle distribution function. We investigate collective effects caused by a high-energy electron-positron beam traversing a low-energy electron-positron plasma for an astrophysically interesting range of physical parameters. The principal result of this paper is to identify transverse unstable waves whose phase propagation may occur at any arbitrary angle (other than zero) with respect to the magnetic field but whose group velocity is along the magnetic field and approximately the speed of light. It is suggested that the observed radio pulses from pulsars may be caused by the focusing of these transverse waves along the open field lines extending from a pulsar's polar cap to the light cylinder.
Hardee, P. E.↗