Search Publications
Template Ultraviolet to Near-Infrared Spectra of Star-forming Galaxies and Their Application to K-Corrections
Calzetti, Daniela; Storchi-Bergmann, Thaisa; Bohlin, Ralph C. +3 more
Template UV-optical spectra of quiescent and starburst galaxies are presented and used to derive K-corrections as a function of morphological type and redshift. IUE observations and archival data are used for the UV template spectra. The optical spectra are from ground-based observations obtained in apertures that match closely the 200 arcsec^2^ I…
O-star mass-loss and wind momentum rates in the Galaxy and the Magellanic Clouds Observations and theoretical predictions.
Lennon, D. J.; Herrero, A.; Pauldrach, A. W. A. +8 more
A new, very fast approximate method is presented to determine mass-loss rates of O-stars from Halpha_ line profiles. The method uses H and HeII departure coefficients from unified model atmospheres parametrized in a simple way as function of wind velocity together with photospheric NLTE line profiles as the inner boundary condition for …
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…
A Database for Galaxy Evolution Modeling
Walborn, Nolan R.; Parker, Joel Wm.; Robert, Carmelle +77 more
This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of the spectra and evolution of galaxies. A broad variety of empirical and theoretical data are discussed here, and the data are made fully available in the AAS CD-ROM Series, Vo. 7. Several empirical stellar libraries are part of th…
X-ray properties of active galactic nuclei with optical FeII emission.
Wang, T.; Brinkmann, W.; Bergeron, J.
ROSAT spectra of 86 Active Galactic Nuclei (AGN) with a broad range of optical FeII strengths have been analyzed. The results of the spectral analysis have been combined with optical and radio data as well as with optical emission line properties collected from the literature to understand the origin of the strong FeII emission and the nature of t…
Multiwavelength Observations of Short-Timescale Variability in NGC 4151. IV. Analysis of Multiwavelength Continuum Variability
Shull, J. M.; Glass, I. S.; Malkan, M. A. +88 more
This paper combines data from the three preceding papers in order to analyze the multi-wave-band variability and spectral energy distribution of the Seyfert I galaxy NGC 4151 during the 1993 December monitoring campaign. The source, which was near its peak historical brightness, showed strong, correlated variability at X-ray, ultraviolet, and opti…
Projected Rotational Velocities of O-Type Stars
Penny, Laura R.
I present an homogeneous set of projected rotational velocities for 177 O stars based upon lUE high- dispersion spectra of the UV photo spheric lines. The line widths are estimated by cross-correlating each spectrum with the spectrum of a narrow-lined O star (HD 34078), and the widths of the cross-correlation functions are transformed to projected…
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…
Long- and short-term variability in O-star winds. I. Time series of UV spectra for 10 bright O stars.
Kaper, L.; Henrichs, H. F.; Nichols, J. S. +3 more
An atlas of time series of ultraviolet spectra is presented for 10 bright O stars. The spectra were obtained with the International Ultraviolet Explorer during seven observing campaigns lasting several days over a period of 6years. The UV P Cygni lines in 9 out of the 10 studied stars exhibit a characteristic pattern of variability in the form of …
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…