Search Publications
A Statistical Study of Accretion Disk Model Spectra for Cataclysmic Variables
Hubeny, Ivan; Puebla, Raúl E.; Diaz, Marcos P.
We have performed a statistical test of the currently used accretion disk models for cataclysmic variables (CVs) using a set of 33 CVs with steady disks (10 old novae and 23 nova-like systems). The mass transfer rate () for each system was also calculated. Ultraviolet (UV) data were fitted by model spectra using a multiparametric optimization meth…
Star Formation, Radio Sources, Cooling X-Ray Gas, and Galaxy Interactions in the Brightest Cluster Galaxy in 2A0335+096
O'Dea, Christopher P.; Donahue, Megan; Voit, G. Mark +2 more
We present deep emission-line imaging taken with the new SOAR Optical Imager of the brightest cluster galaxy (BCG) in the nearby (z=0.035) X-ray cluster of galaxies 2A0335+096. We also present our analysis of additional, multiwavelength observations for the BCG, including long-slit optical spectroscopy, archival VLA radio data, Chandra X-ray imagi…
An Update on the X-Ray Transient Narrow-Line Seyfert 1 Galaxy WPVS 007: Swift Observations of UV Variability and Persistence of X-Ray Faintness
O'Brien, Paul T.; Schady, Patricia; Leighly, Karen M. +3 more
We report on the detection of UV variability and the persistence of X-ray faintness of the X-ray transient narrow-line Seyfert 1 galaxy WPVS 007 based on the first year of monitoring with Swift between 2005 October and 2007 January. WPVS 007 has been an unusual source. Although it was X-ray-bright in the ROSAT All-Sky Survey, it has been extremely…
Spectral Analysis of the Pre-WN Candidate HD 326823
Marcolino, W. L. F.; de Araújo, F. X.; Lorenz-Martins, S. +1 more
We present a spectral analysis of the peculiar emission-line star HD 326823. As has been reported in the literature, this object seems to be a rare, massive star entering the Wolf-Rayet (W-R) phase. In order to confirm its evolutionary status, we used the radiative transfer code CMFGEN to obtain its physical parameters and chemical abundances for …
The Ultraviolet Spectra of the Weak Emission Line Central Stars of Planetary Nebulae
Marcolino, W. L. F.; de Araújo, F. X.; Junior, H. B. M. +1 more
The UV spectra of all "weak emission line central stars of planetary nebulae" (WELSs) with available IUE data are presented and discussed. We performed line identifications and equivalent-width and flux measurements for several features in the spectra. We found that the WELSs can be divided into three different groups regarding their UV spectra: (…
Properties of the ζ Aur-Type Binary System 22 Vul = QS Vul
Eaton, Joel A.; Shaw, Felecia G.
The 22 Vul system is important for studying the winds and chromospheres of cool evolved stars because the G4 I component is rotating rapidly and probably faster than synchronously. We discuss the system's physical properties in the context of a wide range of constraints on them and propose values that may be marginally better than previous ones (s…
New Ultraviolet Observations of AM CVn
Eracleous, Michael; Wade, Richard A.; Flohic, Hélène M. L. G.
We have obtained observations of the ultraviolet spectrum of AM CVn, an ultrashort-period helium cataclysmic variable, using the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope (HST). We obtained data in time-tag mode during two consecutive orbits of HST, covering 1600-3150 and 1140-1710 Å, respectively. The mean spectrum is…
FUSE Observations of the Dwarf Novae UU Aql, BV Cen, and CH UMa in Quiescence
Szkody, Paula; Sion, Edward M.; Godon, Patrick +1 more
We report on FUSE spectra of three U Gem-type, long-period dwarf novae, UU Aql, BV Cen, and CH UMa, taken during their quiescence intervals. We discuss the line identifications in their spectra and attempt to characterize the source(s) of their FUV flux distribution. Archival IUE spectra of CH UMa and BV Cen in quiescence were identified as having…