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Measurements of Flow Speeds in the Corona Between 2 and 30 R⊙
Llebaria, A.; St. Cyr, O. C.; Michels, D. J. +16 more
Time-lapse sequences of white-light images, obtained during sunspot minimum conditions in 1996 by the Large Angle Spectrometric Coronagraph on the Solar and Heliospheric Observatory, give the impression of a continuous outflow of material in the streamer belt, as if we were observing Thomson scattering from inhomogeneities in the solar wind. Pursu…
A Composite HST Spectrum of Quasars
Kriss, Gerard A.; Zheng, Wei; Davidsen, Arthur F. +2 more
We construct a composite quasar spectrum from 284 HST FOS spectra of 101 quasars with redshifts z > 0.33. The spectrum covers the wavelengths between 350 and 3000 Å in the rest frame, with a peak S/N level of ~130 per Å at ~1200 Å. Since ~90% of the sample quasars have redshift z < 1.5, the spectrum is suitable for studying the wavelength re…
Hubble Space Telescope Images of a Sample of 20 Nearby Luminous Quasars
Schneider, Donald P.; Bahcall, John N.; Kirhakos, Sofia +1 more
Observations with the Wide-Field Camera of the Hubble Space Telescope (HST) are presented for a representative sample of 20 intrinsically luminous quasars with redshifts smaller than 0.30. These observations show that luminous quasars occur in diverse environments that include ellipticals as bright as the brightest cluster galaxies (two), apparent…
The spectrum of comet Hale-Bopp (C/1995 O1) observed with the infrared space observatory at 2.9 astronomical units from the sun.
Altieri, B.; Keller, H. U.; Lellouch, E. +5 more
Eta Carinae and Its Environment
Humphreys, Roberta M.; Davidson, Kris
Eta Carinae (Eta) is one of the most remarkable of all well-studied stars and perhaps the most poorly understood. Observations with the Hubble Space Telescope and other modern instruments have solved a few of the mysteries concerning this object while opening a comparable number of new ones. In this review we first recount some essential backgroun…
Reddening and Star Formation in Starburst Galaxies
Calzetti, Daniela
The reddening properties and the star formation history of a sample of 19 starburst galaxies are investigated using multiwavelength spectroscopy and infrared broad band photometry. New photometric data in the J, H, and K bands of the central starburst regions are supplemented with previously published spectra, covering the wavelength range 0.12-2.…
Peace: a Plasma Electron and Current Experiment
Coates, A. J.; Winningham, J. D.; Grande, M. +13 more
Keck Spectroscopy of Redshift z ~ 3 Galaxies in the Hubble Deep Field
Illingworth, Garth D.; Faber, S. M.; Gronwall, Caryl +6 more
We have obtained spectra with the 10 m Keck telescope of a sample of 24 galaxies having colors consistent with star-forming galaxies at redshifts 2 <~ z <~ 4.5 in the Hubble deep field (HDF). Eleven of these galaxies are confirmed to be at high redshift (zmed = 3.0), one is at z = 0.5, and the other 12 have uncertain redshifts but…
The Cepheid period-luminosity zero-point from HIPPARCOS trigonometrical parallaxes
Catchpole, R. M.; Feast, M. W.
Hipparcos trigonometrical parallaxes of Cepheid variables are used to derive a zero-point for the period-luminosity (PL) relation. Adopting a slope from the Large Magellanic Cloud (LMC), the relation is found to be <M_V>=-2.81 log P-1.43. The standard error of the zero-point is 0.10 mag. Together with metallicity corrections this corresponds…
The Homogeneity of Spheroidal Populations in Distant Clusters
Smail, Ian; Ellis, Richard S.; Dressler, Alan +4 more
The small scatter observed for the (U-V) colors of spheroidal galaxies in nearby clusters of galaxies provides a powerful constraint on the history of star formation in dense environments. However, with local data alone, it is not possible to separate models where galaxies assembled synchronously over redshifts 0 < z < 1 from ones where gala…