Comparison of far-infrared radiation with gamma radiation

The gamma-ray emissivity for the narrow component (FWHM = 2°) at the 0.3–5 GeV range is derived as a function of the galactocentric distance. The narrow component might result from the interaction between cosmic rays and H₂ gas. The mass of gas in the Galactic Center is not large enough to produce the gamma-ray peak, but enough to produce the far-infrared peak. The relation of far-infrared dip and near-infrared hump near l = 356° to gamma-ray hump is discussed.     

Balloon-borne far-infrared spectrophotometry of the galactic center region

Far-infrared observations of the Galactic Center have been carried through with the MPE Im balloon-borne telescope “Golden Dragon”. The measurements are composed of photometric scanning (33–95 μm) of the inner 4′×4′ and low resolution spectroscopy (δ^ν = 10 cm^?1) of the center and of a position approximately 1.5′ to the north. A Mars spectrum has been obtained for calibration. The spatial resolution of the photometry map is increased using the Maximum Entropy Method and the resulting map is compared to other observations in the same and other spectral regions. A clear asymmetry in the ring-like structure around the center indicates the presence of noncircular motions. The shape of the spectra is fairly smooth with at least no prominent dust features. A simple modelling shows a drastic increase of column density within 2 pc from the center and a modest drop over the next 3 pc to the north.     

CygX-1/A candidate of the black hole

Among discrete galactic X-ray sources, Cyg X-1 has been noted for its peculiar features in several respects. It is one of the few sources with a hard power law spectrum extending beyond several hundred keV. Cyg X-1 also distinguishes itself by its profound time variability over a wide range of time scales. The most remarkable incident was that its optical identification with a spectroscopic binary HDE226868 has led to a presumption that it is a black hole. This possibility has induced continuous interests in the physical character of this source in conjunction with the nature of the black hole. The purpose of this paper is to summarize presently available pieces of knowledge on this source to help the design of future experimental and theoretical works, while the complexity of the source characteristics still has prevented us to construct a clear, coherent picture of this source in spite of the fact that numerous observational facts have been accumulated.     

Direct measurement of the composition and spectra of cosmic rays above 1 TeV/amu from Jacee

Direct measurements on cosmic ray protons through iron above about 1 TeV/amu have been performed in a series of balloon-borne experiments with emulsion chambers. The measured energy spectra of protons and helium are power laws with exponents of 2.77 ± 0.09 and 2.72 ± 0.11 in the energy range 5 to 500 TeV and 2 to 50 TeV/amu, respectively. The proton spectrum shows no evidence of the steepening near 2 TeV which was reported by other experiments. Helium has a slightly higher intensity compared to extrapolations from lower energy measurements. The heavier elements, carbon to sulfur, show a small tendency for intensity enhancement in the relative abundance above 10 TeV/amu.     

The modulation collimator in x-ray astronomy

Modulation collimators have been used in recently reported work to determine the angular sizes and celestial positions of the X-ray sources Sco X-1 and Taurus XR-1 (Crab Nebula) with precisions of 15 to 30. The measurements were made by means of four-grid collimators, star photography and optical imaging of the collimators. In the present paper we discuss (1) the principles and uses of various forms of the modulation collimators as they pertain to X-ray astronomy, (2) several methods for determining the celestial positions of X-ray sources with these collimators, (3) the techniques for the alignment and calibration of these detection systems, (4) an image-forming collimator, and finally, (5) some of the optical properties of these grid systems. The modulation collimator is quite versatile and is particularly suited for measurements from spacecraft with relatively poor pointing capability. Thus it should be a useful tool in X-ray astronomy for some years to come.This work was supported in part by the National Aeronautics and Space Administration under contracts NASw-1284 and NASw-1535 and grant NSG-386 and in part by the United States Atomic Energy Commission under contract AT (30-1)2098. In addition, certain portions were carried out at California Institute of Technology under National Aeronautics and Space Administration grant NSG-426 and at the Institute of Space and Aeronautical Sciences, Tokyo.