Search Publications
Detection of Additional Be+sdO Systems from IUE Spectroscopy
Gies, Douglas R.; Wang, Luqian; Peters, Geraldine J.
There is growing evidence that some Be stars were spun up through mass transfer in a close binary system, leaving the former mass donor star as a hot, stripped-down object. There are five known cases of Be stars with hot subdwarf (sdO) companions that were discovered through International Ultraviolet Explorer (IUE) spectroscopy. Here we expand the…
Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. I. Spatially Resolved Mass Outflow Rates for the Seyfert 2 Galaxy Markarian 573
Kraemer, S. B.; Crenshaw, D. M.; Schmitt, H. R. +3 more
We present the first spatially resolved mass outflow rate measurements ({\dot{M}}out}) of the optical emission line gas in the narrow line region (NLR) of a Seyfert 2 galaxy, Markarian 573. Using long slit spectra and [O III] imaging from the Hubble Space Telescope and Apache Point Observatory in conjunction with emission line diagnosti…
The Long-term Secular Mass Accretion Rate of the Recurrent Nova T Pyxidis
Williams, Robert E.; Sion, Edward M.; Godon, Patrick +1 more
We present Hubble Space Telescope ultraviolet spectroscopy of the recurrent nova T Pyxidis obtained more than five years after its 2011 outburst, indicating that the system might not have yet reached its deep quiescent state. The ultraviolet data exhibit a 20% decline in the continuum flux from the pre-outburst deep quiescence state to the post-ou…
Angular Sizes and Effective Temperatures of O-type Stars from Optical Interferometry with the CHARA Array
Gies, Douglas R.; Schaefer, Gail H.; Hillier, D. John +3 more
We present interferometric observations of six O-type stars that were made with the Precision Astronomical Visible Observations beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array. The observations include multiple brackets for three targets, λ Ori A, ζ Oph, and 10 Lac, but there are only preliminary, single observation…
Evolution of the Outflows in NGC 3516
Kraemer, S. B.; Dunn, Jay P.; Parvaresh, Rozhin +1 more
We analyze the 2011 HST/COS spectrum of the Seyfert 1 galaxy NGC 3516, which demonstrates clear changes in one of the intrinsic absorption troughs (component 5), slight evidence of change in a second trough (component 6), and the appearance of a new absorption trough (component 9). We interpret both the changes and the appearance of the new trough…
Ultraviolet Flux Decrease Under a Grand Minimum from IUE Short-wavelength Observation of Solar Analogs
Melis, Carl; Tytler, David; Lubin, Dan
We have identified a sample of 33 Sun-like stars observed by the International Ultraviolet Explorer (IUE) with the short-wavelength spectrographs that have ground-based detections of chromospheric Ca II H+K activity. Our objective is to determine if these observations can provide an estimate of the decrease in ultraviolet (UV) surface flux associa…