Search Publications
Thermal Comptonization and Disk Thermal Reprocessing in NGC 3516
Chiang, James; Blaes, Omer
We present an application of the thermal Comptonization/disk reprocessing model recently proposed by Zdziarski, Lubiński, & Smith. We show that the absence of strong optical variations in the presence of strong concurrent X-ray variations, similar to those found by Hubble Space Telescope (HST)/Rossi X-Ray Timing Explorer (RXTE) monitoring obse…
Chemical Abundances of the Accreting Magnetic White Dwarf in the Polar AM Herculis
Sion, Edward M.; DePasquale, Joseph
We consider the presence of absorption lines due to accreted metals in the photosphere of the magnetic (28 MG) white dwarf in the prototype polar AM Herculis. We have applied the Massa-Fitzpatrick flux-calibration correction to the archival IUE NEWSIPS SWP spectra of AM Her obtained during the optical low states, when the accretion rate is very lo…
Where Are the Absorbers toward Q2302+029?
Bowen, David V.; Jenkins, Edward B.; Pettini, Max +1 more
We present images and spectroscopy of objects close to the sight line of Q2302+029 in order to search for galaxies responsible for the remarkable z=0.7 high-ionization absorption-line system found by Jannuzi et al. This system shows ``normal'' narrow O VI, N V, and C IV lines superimposed on broader (3000-5000 km s-1 wide), unsaturated …
Hipparcos and MAP Studies of the Triple Star π Cephei
Han, Inwoo; Gatewood, George; Pourbaix, Dimitri +2 more
We reexamine the visual and radial velocity data for the π Cephei triple star system and derive the masses of the three components. Our study is based upon the analysis of Hipparcos Intermediate Astrometric Data (IAD) measurements obtained with the red light Thaw refractor's Multichannel Astrometric Photometer (Thaw/MAP) and positions obtained fro…
An Empirical Procedure to Estimate Distances to Stellar Clusters
Allende Prieto, Carlos
A most desirable feature of a standard candle to estimate astronomical distances is robustness against changes in metallicity and age. It is argued that the radii of main-sequence stars with spectral types from solar to A0 show predictable changes with metallicity and detectable changes with evolution. Such stars populate the solar neighborhood an…