9. D. N. Page, S. W. Hawking, "Gamma Rays from Primordial 

 Black Holes," Astrophysical Journal, v. 206(1976). 



10. D. N. B. Hall, "An Atlas of Infrared Spectra of the Solar 

 Photosphere and Sunspot Umbrae in the Spectral Intervals 4040 

 cm-l — 6700 cm-l, 7400 cm-' —8790 cm-', " KPNO Publica- 

 tion (1976). 



Current and future research emphasis. Current 

 research problems in the astronomical sciences 

 continue to be significant and exciting. Discoveries 

 in recent years of objects such as distant radio gal- 

 axies, quasars, pulsars, and pulsating x-ray 

 sources are indicative of the broad range of prob- 

 lems that require study and await explanation. 

 Many of these discoveries are due to observations 

 in new portions of the spectrum and improvements 

 in the instrumentation being used to study the 

 universe. Current emphasis in the Division of As- 

 tronomical Sciences is directed toward the study 

 of these new objects which often exhibit extreme 

 temperatures, densities, and pressures unattainable 

 in terrestrial laboratories. However, the impor- 

 tance of traditional areas such as astrometry, stellar 

 composition, and galactic structure has not dimin- 

 ished, and studies of this type continue. 



At present, particular emphasis is being placed 

 in the following four areas: (1) Development of 

 improved detectors for existing telescopes; (2) 

 studies of high energy processes in radio sources, 

 quasars, pulsars, and x-ray sources; (3) studies of 

 the early and late stages of stellar evolution; and 

 (4) the determination of the composition and 

 physical conditions in the general interstellar med- 

 ium. 



In the near future, emphasis will be placed on 

 areas where we can expect large scientific returns 

 for a modest application of resources. We will con- 

 tinue to explore the new and exciting wavelength 

 regions of the spectrum where recent advances 

 have been made. Support will be provided for mil- 

 limeter and submillimeter wave instrumentation 

 and observations, including the building of a three- 

 element millimeter wave interferometer. More 

 sensitive receiver systems at millimeter wave- 

 lengths will be developed to extend the capabilities 

 of existing telescopes. 



In the infrared, continued development of highly 

 efficient optical and infrared detectors will be sup- 

 ported. This will include the two-dimensional ar- 

 rays which provide much valuable spectral and 

 brightness distribution information. Along with 

 such array detectors, data acquisition and interac- 

 tive processing systems must be developed and 

 made available for a number of major 

 observatories in the country. Infrared and optical 

 interferometry is in its infancy and will be devel- 

 oped in the near future. 



The valuable technique of very long baseline 

 interferometry (VLBI) will receive increasing 



1 96 NATIONAL SCIENCE FOUNDATION 



emphasis. The unequalled angular resolution of 

 this technique is necessary for an improved under- 

 standing of energetic radio sources and quasars. A 

 radio telescope of 25-meter aperture for VLBI 

 observations at wavelengths as short as 1 centime- 

 ter is required in the Midwest to complement the 

 currently available VLBI telescopes. Additionally, 

 the present VLBI stations will require upgrading of 

 their receiver systems and data acquisition and 

 processing instrumentation. Studies will be carried 

 out to determine the need for and design of a dedi- 

 cated VLBI array. The Midwest dish will then be 

 the first element of this dedicated array. 



As rising levels of light and air pollution increas- 

 ingly limit our current optical telescopes, a serious 

 search must be undertaken to identify the optimum 

 dark sky site for a major new astronomical observ- 

 atory in the United States. Such a survey will re- 

 quire a number of years but can be carried on at a 

 low annual cost. Simultaneously, the conceptual 

 design studies for a major new large telescope (ap- 

 erture of 1,000 inches or so) will be undertaken. 

 The results of these studies and of the site survey 

 will determine the timescale on which a major new 

 astronomical center can or should be established. 



The sun is of vital importance to man in terms of 

 climate and as an energy source. In order better to 

 understand the sun, the upcoming solar maximum 

 in 1979-80 (which present indications suggest may 

 be one of the lowest maxima in recent history) 

 should be studied in great detail. This will require 

 some modest support for new instrumentation, but 

 primarily will involve increased support for inves- 

 tigators to obtain and interpret data during the 

 period of the solar maximum. 



To interpret and understand properly the data 

 from many of the studies of stellar atmospheres 

 and the interstellar medium, it is necessary that 

 increased support of theoretical and laboratory 

 studies of astrophysical phenomena be provided. 

 The required increases will be modest compared to 

 the data and understanding expected to emerge. 



The construction of the "very large array" tele- 

 scope will continue. By 1979, it will be the largest 

 aperture synthesis radio telescope in the world. Its 

 sensitivity will be 2 1/2 times that of the Wester- 

 bork array in the Netherlands (currently the 

 largest), and resolution will be comparable to that 

 of optical telescopes (0.2 to 2 arc sec). It will be 

 used to produce maps of radio sources such as 

 quasars enabling a detailed comparative study of 

 these objects in both optical and radio wave- 

 lengths. It will be in great demand by university 

 astronomers and support will be required for ob- 

 servations and interpretation of the data gathered. 



