Search Publications
Abundances and Behavior of 12CO, 13CO, and C2 in Translucent Sight Lines
York, D. G.; Sonnentrucker, P.; Welty, D. E. +1 more
Using UV spectra obtained with FUSE, HST, and/or IUE together with higher resolution optical spectra, we determine interstellar column densities of 12CO, 13CO, and/or C2 for 10 Galactic sight lines with E(B-V) ranging from 0.37 to 0.72. The N(CO)/N(H2) ratio varies over a factor of 100 in this sample, d…
The Abundances of Light Neutron-Capture Elements in Planetary Nebulae. I. Photoionization Modeling and Ionization Corrections
Kallman, T. R.; Dinerstein, Harriet L.; Sterling, N. C.
We have conducted a large-scale survey of 120 planetary nebulae (PNe) to search for the near-infrared emission lines [Kr III] 2.199 µm and [Se IV] 2.287 µm. The neutron (n)-capture elements Se and Kr may be enriched in a PN if its progenitor star experienced s-process nucleosynthesis and third dredge-up. In order to determine Se and Kr…
Virial Masses of Black Holes from Single Epoch Spectra of Active Galactic Nuclei
Bechtold, Jill; Kelly, Brandon C.
We describe the general problem of estimating black hole masses of active galactic nuclei (AGNs) by calculating the conditional probability distribution of MBH given some set of observables. Special attention is given to the case where one uses the AGN continuum luminosity and emission line widths to estimate MBH, and we outl…
Goodness-of-Fit Tests DIFF1 and DIFF2 for Locally Normalized Supernova Spectra
Baron, E.; Branch, David; Danziger, I. J. +3 more
Two quantitative tests DIFF1 and DIFF2 for measuring goodness of fit between two locally normalized supernova spectra are presented. Locally normalized spectra are obtained by dividing a spectrum by the same spectrum smoothed over a wavelength interval relatively large compared to line features, but relatively small compared to continuum features.…