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Lampton, M.

Publications and source records attributed to Lampton, M..

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Gas absorption cell photometer for rocket observations of local interstellar helium

A photometer sensitive in the 584-A line of He I, incorporating a helium-gas absorption cell, has been developed. The helium is confined at a pressure of 0.2 torr between thin-metal-foil broad-band ultraviolet filters. The cell contains sufficient helium to absorb 584-A radiation scattered from atmospheric helium. The ratio of fluxes seen with the cell full and empty provides a valuable datum for fitting models of the local interstellar medium, which is independent of solar 584-A flux, interstellar helium density, and photometer sensitivity.-

Freeman, J.↗
NASA NTRS1976

Extreme ultraviolet survey experiment MA-083

A grazing incidence telescope sensitive to radiation in the 5- to 100-nanometer band was flown in the Apollo service module. On 10 nighttime revolutions, the command and service module was maneuvered to point the instrument at 30 different stellar targets for periods of 1 to 20 minutes, thus constituting the first sensitive search for extreme ultraviolet radiation from nonsolar sources. Several hours of supplementary data were also obtained during nighttime orbits when other experiments in the scientific instrument module bay were operating. Preliminary analysis of a small fraction of the total data indicates the definite detection of a strong source of extreme ultraviolet radiation during observations made during revolution 109. The source is located in Coma Berencies. The suggested optical identification is the white dwarf HZ 43. If this association is correct, the star has the highest temperature of any known white dwarf. Regardless of the optical identification, however, this object is the first nonsolar source to be detected in the extreme ultraviolet band.

Bowyer, S.↗
NASA NTRS1976

Interstellar helium flow experiment MA-088

The Apollo Soyuz Test Project Interstellar Helium Glow Experiment (MA-088) studied the motion of helium in the local interstellar medium as that medium passed through the solar system to determine several poorly known properties of the local interstellar gas. The instrument used was a photometer sensitive to two solar extreme ultraviolet spectral lines that are resonantly scattered by helium gas. The instrument surveyed the entire celestial sphere during a series of slow, rolling maneuvers by the Apollo spacecraft. The equipment operated properly, and usable data were obtained.

Bowyer, S.↗
NASA NTRS1976

Discovery of a nonsolar extreme-ultraviolet source

Results are reported for observations of EUV emission from an extrasolar object which were made with a grazing-incidence telescope during the Apollo-Soyuz mission. The total energy flux in the spectral band between 170 and 620 A is estimated to be approximately 4 by 10 to the -9th power erg/sq cm per sec. It is shown that the data support the identification of the EUV object with the ultrasoft X-ray source in Coma Berenices. The source of both emissions is suggested to be the hot white dwarf HZ 43, located at right ascension 13 hr 43 min and declination +29 deg 22 min (1950). The temperature of HZ 43 is estimated as 110,000 K, giving it the highest temperature of any known white dwarf.

Lampton, M.↗
NASA NTRS1976

An ultrasoft X-ray source in Coma Berenices

An intense soft X-ray source with an extraordinary spectrum has been observed in Coma Berenices, 4 deg northeast of and not associated with the Coma cluster of galaxies. Two spectra, obtained at different times in a sounding-rocket flight, indicate that the source temperature in thermal models is less than 1 million K; a power-law model requires photon power-law indices steeper than n = -3. The intensity in the 44-165 A band is of the order of 5 by 10 to the -10th power erg/sq cm/sec, but no flux is present at energies 0.3-2.1 keV to a limit of 1 by 10 to the -10th power erg/sq cm/sec. The lack of bright stars or a supernova remnant in the error box implies that this may be a new class of soft X-ray sources.

Margon, B.↗
NASA NTRS1975

A sensitive search for soft X-rays from Arcturus and Procyon

Sensitive X-ray observations have been obtained of alpha Boo and alpha CMi using rocket-borne large area proportional counters. No flux was detected from either star, yielding limits on intrinsic luminosity in the 75-2000 eV band (6-165 A) as stringent as 10 to the 28-th power ergs per sec depending upon assumed coronal temperature. These are at least an order of magnitude better limits than previously reported values. Upper limits are also set on a mass loss rate of three billionths solar mass per year and on an emission measure of less than 3 times 10 to the 53-rd power per cu cm. If these stars are typical, then giants and subgiants cannot be responsible for a significant fraction of the soft component of the diffuse X-ray background.

Cruddace, R.↗
NASA NTRS1975

The soft X-ray spectrum of the Perseus cluster

The X-ray spectrum of the Perseus cluster in the range 0.1-4.0 keV has been observed. Contrary to the results of previous low-energy rocket observations, no large flux of soft X-rays was found. The X-ray spectrum from 0.1 to 56 keV is consistent with bremsstrahlung from an intracluster gas with T approximately equal to 100 million K. attenuated by the interstellar column density inferred from 21-cm observations. The low-energy X-ray spectrum is not consistent with a nonthermal power-law model with the same slope as that observed at higher energies. The mass of hot intracluster gas required to produce the observed X-ray flux is a small fraction of the gravitational binding mass. The soft X-ray flux, when combined with limits on the radio flux, implies that the cluster is not gravitationally bounded by ionized gas at any temperature.

Davidsen, A.↗
NASA NTRS1975

Large area extreme ultraviolet focusing collector

A grazing incidence one-dimensional focusing collector for use in the extreme ultraviolet is described. The collector has a field of view of 1 x 50 deg, a focal length of 3015 cm, and a total unobstructed area of 224 sq cm. The instrument employs an interchangeable detector package of either channel-electron multipliers or proportional counters which yield a limiting sensitivity of 1.0 photons/sq cm sec A at 170 A and 0.05 photons/sq cm sec A at 90 A, respectively, for one second integrations. The design and calibration of the instrument are described in detail. Data obtained by this instrument during recent rocket flights are presented.

Henry, P.↗
NASA NTRS1975

Soft X-ray spectroscopy of three extragalactic sources

Soft X-ray spectra (0.5 to 5 KeV) acquired with a rocket-borne argon-methane proportional counter are reported for M87, 3C 273, and NGC 4151. The counter sensitivity range allowed derivation of simultaneous information on the magnitude of soft X-ray absorption and the slope of the hard X-ray spectrum. Error estimation techniques for the free parameters of X-ray spectra are analyzed, and the results are applied to the spectra previously reported for these sources. It is shown that the technique used to analyze the previous spectra can drastically underestimate the magnitude of errors, and it is concluded that the proposed division of extragalactic X-ray sources into two groups according to the magnitude of absorption in their spectra is premature.

Margon, B.↗
NASA NTRS1974

The Ranicon - A resistive anode image converter

A versatile photon and charged particle imaging system is described. The Ranicon employs a microchannel electron multiplier plate to convert each detected event into a charge signal. This charge pulse is proximity-focused onto a large-area resistive anode plate equipped with pickup electrodes on its edges. Each event is located electronically by the ratios of the charges collected at the edges or by the differences of the signals' risetimes. One- or two-dimensional pictures are built up by storing events digitally (e.g., a core memory) or in analog form (e.g., a storage oscilloscope). Compact laboratory models have been constructed and tested. Operating characteristics, applications, limitations, and advantages of the Ranicon are discussed.

Lampton, M.↗
NASA NTRS1974

A study of X-ray emission from galactic and extragalactic sources with emphasis on soft and ultra-soft wavelengths

A Black Brant VC rocket was used to scan the Coma and Virgo clusters in order to measure structure in the X-ray sources. The rocket also made measurements of soft X-ray spectra, soft X-ray background flux during a 50 deg scan of the sky, soft X-rays from De Voucoulers 50, set limits to the energy dependence of soft X-ray background spectra, and the flux of solar 584 A radiation resonantly scattered by interstellar He flowing through the solar system.

Bowyer, C. S.↗
NASA NTRS1974

A search for a cosmological component of the soft X-ray background in the direction of M31

Results of an experiment to search for absorption of the soft diffuse X-ray background by M31, the Andromeda Nebula, are presented. Both X-ray and 21-cm observations were obtained with high spatial resolution; the X-ray detector had a 2-degree field of view, and the 21-cm data were taken with 20-minute resolution. The results establish that at least 48 percent of the soft X-ray flux has a local source, but that the remainder may be of distant origin and therefore of cosmological significance.

Margon, B.↗
NASA NTRS1974

Observation of X-ray emission from M31

Observation of X-ray emission from M31 in the 0.5- to 5.0-keV band, using rocket-borne proportional counters. The integrated flux corresponds to (2.2 plus or minus 0.6) x 10 to the 39th ergs/sec at M31, and is confined chiefly to a region coinciding with the optical image of the galaxy. The spectrum has a slope similar to the bright Galactic X-ray sources. The intensity, spectral, and spatial data suggest that the bulk of X-ray emission from M31, and by inference from most normal galaxies, is due to a small group of highly luminous sources, in agreement with the Galactic X-ray luminosity function.

Bowyer, S.↗
NASA NTRS1974

Extreme ultraviolet spectrometer for space research

A normal incidence spectrometer for use in the wavelength region from 200 to 1270 A has been developed. The design and calibration of the instrument are described in detail. The spectrometer can be employed to detect extreme UV radiation at a minimum flux level of 1 rayleigh with a spectral resolution of 40 A and a spatial resolution of 6 deg. Data on the extreme UV night sky spectrum between 780 and 1270 A obtained with this instrument on a recent rocket flight are presented.

Kumar, S.↗
NASA NTRS1974

Cosmic far ultraviolet background

The expected intensities of various possible components of the far ultraviolet background are discussed. It is concluded that existing results do not place interesting constraints on the density of the intergalactic medium (IGM). Current techniques and instrumentation for far ultraviolet astronomy are, however, sufficient to achieve vastly improved limits. New observations are required to determine whether the IGM can be detected in the far ultraviolet or whether the extragalactic component of the background is masked by radiation with a more local origin.

Davidsen, A.↗