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Far-Ultraviolet (912--1900 Angstrom ) Energy Distribution in Early-Type Main-Sequence Stars
Chavez, M.; Holberg, J. B.; Stalio, R.
We present the comparison between observed far-ultraviolet (FUV) fluxes of early-type stars and those predicted by the most recent classical LTE, line-blanketed models of Kurucz. High-quality lUE spectra from the Uniform Low Dispersion Archive (ULDA) of more than 100 stars are selected. The averages of the observed fluxes, normalized to the visual…
Detection of a solar particle event at an heliolatitude of 73.8°S
Pick, M.; Forsyth, R. J.; Lanzerotti, L. J. +2 more
We report the observations of an electron event at a heliolatitude of 73.8°S, the highest latitude interplanetary solar event reported to date. This event was detectable because the interplanetary background was not obscured by electrons produced in co- rotating interaction regions. The event was associated with an interplanetary type III burst an…
The HST ultraviolet spectrum of the nucleus of NGC 1275: Fermi-accelerated Lyalpha emission
Fabian, A. C.; Johnstone, R. M.
We present an HST FOS spectrum of the nucleus of NGC 1275. The narrow part of the Lyalpha line is double-peaked, with one emission line centred at the systemic velocity of the 5000 km s^-1 system and the other blueshifted by ~450 km s^-1. We show that the short-wavelength component is probably formed by Fermi acceleration across a shock front. The…
IUE Spectroscopy of the Nova-Like Variable BZ Cam: Characteristics of its Peculiar Wind Outflow
Sion, Edward M.; Fabian, Dirk; Griffith, Daniel
We have analyzed 15 IUE low resolution SWP spectra of the peculiar hot nova-like object BZ Camelopardalis (= 0623+71), which is associated with a bow shock nebula. We determined approximate relative orbital phases of a series of spectra obtained continuously over a 28 hour time baseline by using the newly determined orbital period (P=0.1535 days) …
Results on TYCHO photometry.
Snijders, M. A. J.; Grewing, M.; Evans, D. W. +8 more
The final Tycho database will contain astrometric and photometric data for about 1 million stars. Here we discuss the results of the Tycho photometric calibration for about 80% of the data acquired by the star mapper of the Hipparcos satellite and estimate the photometric precision in the final Tycho photometric data base. For a non-variable star …
The UV properties of normal galaxies. II. The ``non-IUE'' data.
Longo, G.; Capaccioli, M.; Rifatto, A.
In the last decade several satellite and balloon borne experiments have collected a large number of ultraviolet fluxes of normal galaxies measured through apertures of various sizes and shapes. We have homogenized this data set by deriving scale corrections with respect to IUE. In a forthcoming paper these data will be used to derive standard lumi…
On the evolutionary status of the LMC cluster NGC 2004.
Caloi, V.; Cassatella, A.
IUE observations of hot stars in the LMC young cluster NGC 2004 have been used to derive effective temperatures and bolometric luminosities well below the turn-off. No star is found close to the upper main sequence. Massive stars appear arranged on a vertical sequence at temperatures much lower than those of the ZAMS. Among the fainter objects, th…
Absolute Magnitudes and Colors of A-F Supergiants from Near-Infrared Features. II. The Galactic Sample
Peterson, Deane M.; Slowik, Donald J.
In this paper we extend the calibration of the infrared oxygen triplet at λ7774 Å as a luminosity indicator in A and F supergiants. We add five members of southern Galactic clusters to the nine northern objects previously considered, and find them completely consistent with the earlier relations. The result is a substantially improved fit between …
Hubble Space Telescope Observations of the Very Low Mass Companion to Gliese 105A
Golimowski, David A.; Schroeder, Daniel J.; Uomoto, Alan +1 more
Hubble Space Telescope images of the astrometric binary Gl 105A confirm the previous ground-based detection of a faint, very red companion (Gl 105C) located 3."39 from Gl 105A at P.A. 290 deg. The instrumental magnitudes of Gl 105C are V555 = 16.86 and I814 = 13.54. The observed position of Gl 105C differs significantly from the positions expected…
Lyman α emission from galaxies: the case of absorption line selected galaxies at z~0.3-0.4.
Buat, V.; Bergeron, J.; Deharveng, J. -M.
Three galaxies, at moderate redshifts (z~0.3-0.4) and identified as causing MgII absorption lines in the spectra of the quasars 0229+131, 1127-145 and 1209+107, have been observed with the Faint Object Spectrograph on-board the Hubble Space Telescope. The spectra have been obtained with the large aperture (4.3x1.4" effective), at a resolution (poi…