Science Archives Publication System

The Extreme Ultraviolet Spectrograph: A Radial Groove Grating, Sounding Rocket--borne, Astronomical Instrument

DOI: 10.1086/191844 Bibcode: 1993ApJS...89..211W

Wilkinson, Erik; Green, James C.; Cash, Webster

The design, calibration, and sounding rocket flight performance of a novel spectrograph suitable for moderate-resolution EUV spectroscopy are presented. The sounding rocket-borne instrument uses a radial groove grating to maintain a high system efficiency while controlling the aberrations induced when doing spectroscopy in a converging beam. The i…

1993 • The Astrophysical Journal Supplement Series

Exosat 4

Optical, X-ray and γ-ray observations of compact objects in globular clusters

DOI: 10.1016/0273-1177(93)90169-C Bibcode: 1993AdSpR..13l.597G

Grindlay, J. E.

In the past three years, a new era of study of globular clusters has begun with multiwavelength observations from the current generation of astronomical telescopes in space. We review the recent results obtained from our studies of compact binaries and x-ray sources in globulars with ROSAT and HST as well as our balloon-borne hard x-ray telescope …

1993 • Advances in Space Research

eHST 4

Dust in the planetary system

DOI: 10.1016/0273-1177(93)90063-H Bibcode: 1993AdSpR..13j.139G

Grün, E.

A continuous spectrum of particulates ranging from m-sized objects down to molecular sizes is found almost everywhere in the planetary system: in interplanetary space and surrounding planets. Remote observations and in situ analysis provide information on their abundance and properties. Zodiacal dust particles displayed their low eccentricity, low…

1993 • Advances in Space Research

Ulysses 4

Systematic deformations of the apparent almucantar as derived from Danjon astrolabes in Paris and Santiago de Chile

Bibcode: 1993A&A...274..621P

Pesek, I.; Vondrak, J.; Chollet, F. +1 more

Systematic deformations of apparent almucantar based on long series of observations with Danjon astrolabes in Paris and Santiago de Chile are derived. It is shown that their amplitudes of order of 0".1 - 0".2 have significant seasonal character. Comparison of the results based on two different catalogs (FK4 and FK5) make us believe that at least 5…

1993 • Astronomy and Astrophysics

Hipparcos 3

Pulsar studies with GRO-COMPTEL

DOI: 10.1016/0273-1177(93)90187-G Bibcode: 1993AdSpR..13l.727B

Strong, A. W.; Schönfelder, V.; Kuiper, L. +9 more

Pulsar measurements performed by the experiment COMPTEL, aboard the Compton Gamma Ray Observatory, are described. The main results refer to the Crab and Vela pulsars whose pulse shape characteristics are given in some detail and light curves are compared with those above 50 MeV, as observed by the COS-B satellite. No other gamma-ray pulsars have b…

1993 • Advances in Space Research

COS-B 3

Line blanketing by iron group elements in non-LTE model atmospheres of hot stars

DOI: 10.1007/BF00771055 Bibcode: 1993SSRv...66..147D

Dreizler, Stefan; Werner, Klaus

We report on our recent progress in modeling non-LTE atmospheres of O-stars including blanketing by lines from the iron group elements. The numerical method to account for the huge number of atomic levels and line transitions is presented. Results of exploratory model calculations examining the effects on the temperature structure, the hydrogen an…

1993 • Space Science Reviews

IUE 3

X-ray spectral variability of the Seyfert galaxy NGC 4593.

Bibcode: 1993A&A...273..397G

Ghosh, K. K.; Soundarajaperumal, S.

X-ray (0.1-10 keV) spectra of NGC 4593 were obtained with EXOSAT on seven epochs between 1984 and 1986 using the low and medium energy detectors. Detailed results of the spectral analysis of the seven spectra (obtained from the EXOSAT database) of this galaxy are presented here. Power-law, two power-law, thermal bremsstrahlung and broken power- la…

1993 • Astronomy and Astrophysics

Exosat 3

The Spectral Form and Evolution of Interplanetary Ion Events from Jupiter

Bibcode: 1993ICRC....3..342D

Simnett, G. M.; Krimigis, S. M.; Tappin, S. J. +4 more

1993 • 23rd International Cosmic Ray Conference (ICRC23), Volume 3

Ulysses 3

Evidence for accelerated electrons upstream from Jupiter's bow shock: Ulysses results

DOI: 10.1016/0032-0633(93)90090-O Bibcode: 1993P&SS...41..833C

Chaizy, P.; Anderson, K. A.; Lin, R. P. +1 more

Several transient increases of electrons with energies in the range 40-100 keV have been detected upstream and immediately downstream from the Jovian bow shock (and only in these regions), by instruments on the Ulysses spacecraft during February 1992. The energy spectra of these electrons differ markedly from the energy spectrum of the trapped mag…

1993 • Planetary and Space Science

Ulysses 3

Hubble Space Telescope Observations of the Center of Globular Cluster M15

DOI: 10.1086/133265 Bibcode: 1993PASP..105..969Y

Yanny, Brian

Images of the dense center of globular cluster M15 (NGC 7078) have been obtained with the Hubble Space Telescope in the V and I filters. Accurate photometry is possible in the very densest part of the cluster center with rms errors of <0.3 magnitudes for stars down to the main sequence turnoff. Evidence for radial segregation between horizontal…

1993 • Publications of the Astronomical Society of the Pacific

eHST 3