摘要:

The next generation gamma‐ray spectrometer after the planned Nuclear Astrophysics Explorer (NAE) could be based on the Moon to use the lunar regolith for shielding the detectors from cosmic rays and neutrons. This increased shielding over what could reasonably be put in low‐Earth orbit would provide a narrow line sensitivity (3&sgr;) of ∼2×10−7photons cm−2s−1at 1 MeV in 106s, which is about 10 times better than the NAE and 100 times better than GRO/OSSE.

ISSN:0094-243X    

DOI:10.1063/1.39303

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The unambiguous association of discrete gamma‐ray sources with objects radiating at other wavelengths, the separation of discrete sources from the extended emission within the Galaxy, the mapping of gamma‐ray emission from nearby galaxies and the measurement of structure within a discrete source cannot presently be accomplished at gamma‐ray energies. In the past the detection processes used in high‐energy gamma‐ray astronomy have not allowed for good angular resolution. This problem can be overcome by placing gamma‐ray detectors on the Moon and using the horizon as an occulting edge to achieve arcsec resolution. For the purposes of discussion, this concept is examined for gamma rays above 100 MeV for which pair production dominates the detection process and locally‐generated nuclear gamma rays do not contribute to the background.

ISSN:0094-243X    

DOI:10.1063/1.39304

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Extension of gamma‐ray astronomy to energies above the practical range of the Gamma Ray Observatory (GRO) will require an instrument with an effective area of greater than 10 square meters, exposure times of several weeks, and enough mass to contain gamma‐ray‐generated electromagnetic showers ≳5 GeV. A relatively modest water Cherenkov detector located on the moon could meet these criteria and would have some advantages over conventional techniques. A possible detector configuration is discussed.

ISSN:0094-243X    

DOI:10.1063/1.39305

出版商:AIP    

年代:1990

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.39362

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A large array of astronomical X‐ray detectors can be constructed at a lunar base, and maintained there for a long time. Such an array permits development of a new astronomical subdiscipline based on collection of very large numbers of X‐ray photons from bright X‐ray sources With such data qualitatively new experimental issues can be addressed, in gravitational physics, nuclear physics, and magnetospheric effects. Fundamental questions such as the existence of General Relativistic instabilities in rapidly rotating objects or the Probing or orbits near a black hole can be investigated.

ISSN:0094-243X    

DOI:10.1063/1.39306

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

X‐ray interferometry has the potential for observations of unprecedented angular resolution and far reaching astrophysical consequences. I discuss general requirements for constructing x‐ray interferometers. I then present three x‐ray interferometer observatory concepts based on the Michelson stellar interferometer: two sub‐milliarcsecond interferometers which can resolve nearby stellar coronae and jets in AGN’s, and a sub‐microarsecond resolution design which could resolve and measure the diameters and inclinations of accretion disks in AGNs and determine the orbital parameters of x‐ray binaries. Two of the designs exploit the large angle reflection capabilities of multilayer mirrors. Optical interferometric techniques being developed for gravity wave beam detectors provide the necessary metrology. Tracking is performed by parallel optical interferometers. Observations of sources fainter than 0.1 of 3C273 and Capella should be possible. For the sub‐microarsecond interferometer, a lunar platform is essential for providing a stable, kilometer‐length baseline.

ISSN:0094-243X    

DOI:10.1063/1.39308

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We propose as the first telescope accompanying our return to the moon a simple but elegant two meter class instrument capable of producing an extraordinary survey of the Universe. This telescope produces a deep image of the sky obtained simultaneously in several broad bandpasses in the wavelength range from about 0.1 to 2 microns, with diffraction limited imaging in the infrared and approximately 0.1 arcsec resolution at shorter wavelengths. In an 18.6 year mission, the survey would include approximately 2% of the sky with multiple observations of all the surveyed area. This survey is accomplished with a telescope which as has no moving parts and requires no continuing support beyond initial deployment.

ISSN:0094-243X    

DOI:10.1063/1.39310

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The function of a workshop is to develop and refine ideas and concepts. In this paper we present a subset of scientific programs addressable by the Lunar Transit Telescope (LTT), a meridian‐pointing imaging survey telescope with no moving parts. We invite you to comment on these proposed scientific programs of LTT and to suggest new programs which might be addressed by this instrument. It is our conclusion from this exercise that the scientific programs of the LTT easily justify its implementation as an early astronomical facility accompanying our return to the moon.

ISSN:0094-243X    

DOI:10.1063/1.39311

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A 16 m passively‐cooled, diffraction‐limited, filled‐aperture lunar‐based telescope would have unprecedented power for tackling a wide range of the most fundamental astrophysical problems, from the detection of earth‐like planets to the structure of (forming?) galaxies atz≳1. The telescope would have a lightweight, segmented primary with active wavefront sensing and control for diffraction‐limited performance into the UV. The structure and optics would be passively‐cooled to 100 °K, lowering the background in the 3–4 &mgr;m zodiacal ‘‘window’’ to less than 10−6of that from the ground. State‐of‐the‐art mosaics of detectors would give diffraction‐limited imaging and spectroscopy over a field ≳2 arcmin from 0.3 &mgr;m to beyond 10 &mgr;m, and to nearly 1 arcmin in the UV. The observatory would combine remarkable imaging performance, with resolutions ranging from 2–3 mas in the UV to some 40–60 mas in the zodiacal ‘‘window’’ at 3 &mgr;m, with even greater capability for spectrographic observations of faint and/or low surface brightness objects at the highest spatial resolution.

ISSN:0094-243X    

DOI:10.1063/1.39312

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A Lunar optical interferometer with kilometric baselines and large collecting area will be able to make astronomical observations with angular resolution and sensitivity many orders of magnitude beyond earth based or orbital based instruments. Among the many astronomical observation that are possible with such an instrument, a few stand out. The imaging of the central energy source of AGN’s, the discovery of Earth‐like planets around nearby stars, and the measurement of the proper motion of extra‐galactic object to determine the isotropy of the Hubble expansion are a few of the astrophysical observations possible with a Lunar interferometer. This paper examines a few design configurations to determine the interaction of science objectives and the architecture of an instrument that will have 10 microracsec imaging resolution and 0.1 microarcsec astrometric accuracy.

ISSN:0094-243X    

DOI:10.1063/1.39313

出版商:AIP    

年代:1990

数据来源: AIP