Search Publications
Rapid Variability in S5 0716+714 Across the Electromagnetic Spectrum
Quirrenbach, A.; Wagner, S. J.; Zensus, J. A. +14 more
We have investigated the rapid variations of the BL Lac object S5 0716+714 in the radio, optical, ultraviolet, and x-ray regimes. Several simultaneous multifrequency campaigns have been carried out. Here we describe the complete analysis of a four-week monitoring campaign at three radio and three optical frequency bands, simultaneous optical-UV an…
Spectrophotometric Standards From the Far-UV to the Near-IR on the White Dwarf Flux Scale
Bohlin, Ralph C.
The second generation instruments to be installed in 1997 on the Hubble Space Telescope (HST) require spectrophotometric standard stars for flux calibrations to 1.1 µm for the imaging spectrograph (STIS) and to 2.5 µm for the infrared camera (NICMOS). Calculated model atmosphere flux distributions from 0.1 to 3 µm for four pure h…
The Final Archive and Recalibration of the International Ultraviolet Explorer (IUE) Satellite
Nichols, Joy S.; Linsky, Jeffrey L.
Since 1978 the International Ultraviolet Explorer (lUE) satellite has been acquiring the largest collection of astronomical ultraviolet spectra that will likely be obtained in the foreseeable future. The more than 100 000 spectral images, from which low and high dispersion spectra are extracted, include a very broad range of sources from solar sys…
V1974 Cygni 1992: Optical and Ultraviolet Evolution and Analysis
Sonneborn, G.; Shore, S. N.; Starrfield, S. +3 more
We have obtained optical spectrophotometry of V1974 Cygni (Nova Cygni 1992), the brightest nova since 1975, from day 4 to 540 after visual maximum, which we have combined with ultraviolet spectrophotometry to study the ejecta. We show high quality ultraviolet and optical spectra at each major evolutionary phase, identify the lines present during t…
The Inscrutable Hot Component in the Symbiotic Binary Z Andromedae
Mikolajewska, Joanna; Kenyon, Scott. J.
We analyze optical and ultraviolet spectroscopic observations of the symbiotic binary star Z Andromedae. This system consists of an M3 -M4 giant and a hot component surrounded by an ionized nebula. The orbital mass function is consistent with Mg∼Msun and Msunh∼0.5-1 Msun as in other…
The Hot Component of RS Ophiuchi
Mikolajewska, Joanna; Kenyon, Scott J.; Wade, Richard A. +2 more
We analyze optical and ultraviolet spectrophotometry of the quiescent recurrent nova RS Ophiuchi. Our preferred model for this binary consists of an M-type giant and a B-type shell star with a luminosity of Lh∼100-600 Lsun. The ejecta from the recent outburst are slightly enhanced in helium relative to the solar abundance, wh…
The Stellar Initial Mass Function in the Giant HII Region NGC 595
Parker, Joel Wm.; Malumuth, Eliot M.; Waller, William H.
As part of a larger effort to study the resolved and composite properties of the giant H II regions in Messier 33, we have analyzed multiband HST/WFPC-2 images of NGC 595 in terms of the ionizing cluster's resolved stellar population. Photometric reductions of the PC images yield 100 stars on the UV image, 272 stars on the U image, 345 stars on th…
Study of Time Varitions of UV Continuum and Emission Lines in 3C 390.3
Zheng, Wei
Based on the IUE SWP spectra obtained between 1978 and 1994, the variations of the UV continuum and the Lyα and C IV emission lines of the broad-line radio galaxy 3C 390.3 are studied. The UV continuum between 1220 and 1990 A has varied considerably. In 1991 August, the flux at 1360 A reached a maximum level of 1.3 x 10^14^ erg cm^-2^ s^-1^ A^-1^,…
IUE Observations of Four Known/Suspected Magnetic Cataclysmic Variables
Szkody, Paula; Silber, Andrew
We present lUE spectra of the known magnetics (RX J0515+0105, H1752+081 [V2301 Oph]) and the suspected magnetics (H0459+246 and H0857-242 [VZ Pyx]). The flux limit for H0459+246 is consistent with either a magnetic system or a very large value for the reddening. The AM Her system with the longest orbital period (RX 10515+0105) has a very high UV l…
The Evolution of Red Galaxies in Clusters T z=0.5
Hoessel, John G.; Gunn, James E.; Oke, J. B.
A program was carried out at Palomar Observatory to study seven clusters of galaxies all at redshifts near 0.5. Observations consisted of g, r, i, and z broadband Gunn photometry using 4-shooter, and ultraviolet u and violet v photometry using a CCD photometer at the prime focus of the Hale 5 m telescope. The u and v filters reach rest wavelengths…