Search Publications
An Empirical Ultraviolet Template for Iron Emission in Quasars as Derived from I Zwicky 1
Vestergaard, M.; Wilkes, B. J.
We present an empirical template spectrum suitable for fitting and subtracting/studying the Fe II and Fe III emission lines in the rest frame ultraviolet spectra of quasars and active galactic nuclei, the first empirical ultraviolet iron template to cover the full range of 1250-3090 Å. Iron emission is often a severe contaminant in optical-ultravi…
The Distribution of Thermal Pressures in the Interstellar Medium from a Survey of C I Fine-Structure Excitation
Tripp, Todd M.; Jenkins, Edward B.
We used the Space Telescope Imaging Spectrograph (STIS) with its smallest entrance aperture (0.03" wide slit) and highest resolution echelle gratings (E140H and E230H) to record the interstellar absorption features for 10 different multiplets of neutral carbon at a resolving power of λ/Δλ=200,000 in the UV spectra of 21 early-type stars. Our objec…
NICMOS Observations of High-Redshift Radio Galaxies: Witnessing the Formation of Bright Elliptical Galaxies?
Pentericci, L.; Fosbury, R.; Röttgering, H. J. A. +3 more
We present the results of a near-infrared imaging program of a sample of 19 radio galaxies with redshift between 1.7 and 3.2, using the NICMOS Camera 2 on the Hubble Space Telescope (HST). The galaxies were observed in H band, which, for 18 of the 19 targets, samples the rest-frame optical emission longward of the 4000 Å break. For many sources th…
The MACHO Project: Microlensing Detection Efficiency
Alcock, C.; Allsman, R. A.; Alves, D. R. +21 more
The MACHO project is a search for dark matter in the form of massive compact halo objects (MACHOs). The project has photometrically monitored over forty million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge in search of rare gravitational microlensing events caused by these otherwise invisible objects.…
Emission-Line Ratios for [N II] in Gaseous Nebulae and a Comparison between Theory and Observation
Feibelman, W. A.; Keenan, F. P.; Aller, L. H. +1 more
R-matrix calculations of electron impact excitation rates among the 2s22p2 3P, 1D, 1S, and 2s2p3 5S levels of N II are presented. These results are used in conjunction with other recent calculations of electron impact excitation rates and Einstein A-coefficients for N II …