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1994

Astrophysics and Astronomy

Ultraviolet Astronomy

Articles 1 - 2 of 2

Full-Text Articles in Physics

The Optical-Ultraviolet-Γ-Ray Spectrum Of 3c 279, Hagai Netzer, D. Kazanas, Beverley J. Wills, D. Wills, Han Mingsheng, M. S. Brotherton, J A. Baldwin, Gary J. Ferland, I. W. A. Browne Jul 1994

The Optical-Ultraviolet-Γ-Ray Spectrum Of 3c 279, Hagai Netzer, D. Kazanas, Beverley J. Wills, D. Wills, Han Mingsheng, M. S. Brotherton, J A. Baldwin, Gary J. Ferland, I. W. A. Browne

Physics and Astronomy Faculty Publications

We have obtained spectrosocpy of the violently variable quasar 3C 279, simultaneous with γ-ray observations, in 1992 April. Our combined optical (McDonald Observatory and Cerro Tololo InterAmerican Observatory (CTIO) and ultraviolet (HST) observations, made when the source was faint, show a very steep power-law continuum (Fν∝ν-1.95) and strong broad emission lines. This is the first time that the broad ultraviolet lines of this object have been measured, and we note several unusual properties of the spectrum. In particular, the profiles of C IV λ1549 and Mg II λ2798 are asymmetric, with very ...


Hot Gas And The Origin Of The Nebular Continuum In Novae, Pedro Saizar, Gary J. Ferland Apr 1994

Hot Gas And The Origin Of The Nebular Continuum In Novae, Pedro Saizar, Gary J. Ferland

Physics and Astronomy Faculty Publications

A featureless blue continuum (with constant fν) is a defining feature of declining classical novae. The fact that fν is constant into the infrared, and the absence of a Balmer jump, suggests that this continuum originates in hot tenous gas. The electron temperature and density of the hot gas phase of classical nova QU Vul 1984 are estimated from ground-based optical and IUE ultraviolet observations. This region has a temperature of 105 - 106, and a density in the range of 2 x 104 to 3 x 105cm-3. In addition, a colder, denser ...