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An unprecedented UV/optical flare in TV Columbae.
Szkody, P.; Mateo, M.
A surprising, 2 mag, short time scale (hr) outburst of TV Col (2A 0526-328) was observed simultaneously at IUE and optical wavelengths in 1982 November. During this 'flare', the IUE emission lines of N v 1240, C IV 1550, and He II 1640, intensified by more than an order of magnitude and developed P Cygni profiles, indicating mass loss. Continuum f…
A study of the diffuse galactic gamma radiation.
Fichtel, C. E.; Kniffen, D. A.
The observed diffuse galactic gamma radiation is compared to that predicted from galactic cosmic ray interactions with galactic matter and photons, assuming that on a broad scale the galactic cosmic rays in the plane are correlated with matter density. Recent considerations of the galactic diffuse matter distribution, particularly the molecular hy…
Evidence for 4.4 hour periodic dips in the X-ray flux from 4U 1755-33.
Parmar, A. N.; White, N. E.; Kahn, S. M. +3 more
The paper reports the discovery by the EXOSAT Observatory of three equally spaced dips in the flux from 4U 1755 - 33 that suggest the binary period of this system to be 4.4 hr. The duration of each dip is of order 30 minutes with considerable variability within each event on time scales between 30 and 600 s. The variations are spectrally independe…
The unique planetary nebula NGC 2818.
Dufour, R. J.
The planetary nebula NGC 2818, or PK 261 + 8 deg 1, is of special interest due to its apparent association with a Population I open cluster (of the same designation). The results of new observations of the nebula are presented, including interference-filter imagery, photoelectric photometry, and ground-based and IUE spectroscopy. Analysis of its c…
Winds in collision. II. an analysis of the X-ray emission from the eruptive symbiotic HM Sge.
Stencel, R. E.; Willson, L. A.; Wallerstein, G. +1 more
X-ray emissions from HM Sge obtained in 1981 from the HEAO-2 satellite are analyzed and compared quantitatively with observations of HM Sge made in 1980 and of HM Sge, V 1016 Cyg, and RR Tel made in 1979. The change in the X-ray emission from HM Sge between 1979 and 1981 is found to be consistent with the X-ray luminosity and/or temperature of the…
Spectrophotometry of extreme helium stars : ultraviolet fluxes and effective temperatures.
Heber, U.; Drilling, J. S.; Lynas-Gray, A. E. +1 more
Ultraviolet flux distributions are presented for the extremely helium rich stars BD +10 deg 2179, HD 124448, LSS 3378, BD -9 deg 4395, LSE 78, HD 160641, LSIV -1 deg 2, BD 1 deg 3438, HD 168476, MV Sgr, LS IV-14 deg 109 (CD -35 deg 11760), LSII +33 deg 5 and BD +1 deg 4381 (LSIV +2 deg 13) obtained with the International Ultraviolet Explorer (IUE)…
Diffuse LY alpha emission around NGC 1275.
Fabian, A. C.; Nulsen, P. E. J.; Arnaud, K. A.
The authors report on short wavelength ultraviolet observations (1200 - 1900 Å) of NGC 1275 taken with the International Ultraviolet Explorer satellite. Diffuse Lyα radiation was discovered which is identified with the optical filaments surrounding the galaxy. The lack of a detected ultraviolet stellar continuum limits the number of massive young …
The pulsating extreme helium star BD +13 3224. II. Ultraviolet fluxesand effective temperature variations.
Heber, U.; Lynas-Gray, A. E.; Hill, P. W. +1 more
BD + 13 deg 3224 (V652 Her) is characterized on the basis of low-resolution spectra obtained with the short-wavelength prime camera of the IUE on July 5, 1980, and optical spectra obtained at integration time 200 s with the 3.9-m Anglo-Australian Telescope on May 24 and 25, 1980. The results are presented in tables and graphs and discussed. Static…
How to find galaxies at high redshift.
Hartmann, L. W.; Huchra, J. P.; Geller, M. J.
The UV and optical spectra presented for the blue star-forming galaxies Mrk 357, Mrk 496, and Mrk 26 have sufficiently large redshifts to make Lyman-alpha observations possible. Weak Lyman-alpha emission is observed in Mrk 357 and Mrk 469, with a flux value comparable to that of H-beta, and no detectable Lyman-alpha emission is detected in the cas…
Two new extremely hot pulsating white dwarfs.
Green, R. F.; Bond, H. E.; Grauer, A. D. +1 more
High speed photometry of the extremely hot, nearly degenerate stars PG 1707 + 427 and PG 2131 + 066 reveals that they are low-amplitude pulsating variables. Power spectral analysis shows both to be multiperiodic, with dominant periods of 7.5 and 6.4-6.9 minutes, respectively. Together with the known pulsators PG 1159 - 035 and the central star of …