Search Publications
Far Ultraviolet Spectroscopic Explorer Observations of the Dwarf Nova SW Ursae Majoris during Quiescence
Raymond, J. C.; Lobel, A.; Menou, K. +1 more
We present spectroscopic observations of the short-period cataclysmic variable SW UMa obtained by the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite while the system was in quiescence. The data include the resonance lines of O VI at 1031.91 and 1037.61 Å. These lines are present in emission, and they exhibit both narrow (~150 km s-1<…
A Search for Short-Timescale Microvariability in Active Galactic Nuclei in the Ultraviolet
Dolan, Joseph F.; Clark, L. Lee
We observed four active galactic nuclei (AGNs) (the type 1 Seyfert systems 3C 249.1, NGC 6814, and Mrk 205, and the BL Lac object 3C 371) using the High Speed Photometer on the Hubble Space Telescope (HST) to search for short-timescale microvariability in the UV. Continuous observations of ~3000 s duration were obtained for each system on several …
The O VI and C III Lines at 1032 and 977 Å in Hyades F Stars
Robinson, Richard D.; Carpenter, Kenneth G.; Böhm-Vitense, Erika
We continue our investigations into the mechanisms heating the outer layers of cool dwarf stars. In this study we specifically seek to determine whether in the layers with temperatures around 250,000-300,000 K, in which the O VI lines are emitted, the temperatures are determined by heat conduction from the coronae or by the same processes that hea…
Cosmological Results from High-z Supernovae
Filippenko, Alexei V.; Garnavich, Peter; Riess, Adam G. +22 more
The High-z Supernova Search Team has discovered and observed eight new supernovae in the redshift interval z=0.3-1.2. These independent observations, analyzed by similar but distinct methods, confirm the results of Riess and Perlmutter and coworkers that supernova luminosity distances imply an accelerating universe. More importantly, they extend t…
New Constraints on ΩM, ΩΛ, and w from an Independent Set of 11 High-Redshift Supernovae Observed with the Hubble Space Telescope
Panagia, N.; Wang, L.; Sullivan, M. +45 more
We report measurements of ΩM, ΩΛ, and w from 11 supernovae (SNe) at z=0.36-0.86 with high-quality light curves measured using WFPC2 on the Hubble Space Telescope (HST). This is an independent set of high-redshift SNe that confirms previous SN evidence for an accelerating universe. The high-quality light curves available from …
Rest-Frame Ultraviolet Spectra of z~3 Lyman Break Galaxies
Pettini, Max; Shapley, Alice E.; Steidel, Charles C. +1 more
We present the results of a systematic study of the rest-frame UV spectroscopic properties of Lyman break galaxies (LBGs). The database of almost 1000 LBG spectra proves useful for constructing high signal-to-noise composite spectra. The composite spectrum of the entire sample reveals a wealth of features attributable to hot stars, H II regions, d…
Cosmological Evolution of the Hard X-Ray Active Galactic Nucleus Luminosity Function and the Origin of the Hard X-Ray Background
Ueda, Yoshihiro; Ohta, Kouji; Akiyama, Masayuki +1 more
We investigate the cosmological evolution of the hard X-ray luminosity function (HXLF) of active galactic nuclei (AGNs) in the 2-10 keV luminosity range of 1041.5-1046.5 ergs s-1 as a function of redshift up to 3. From a combination of surveys conducted at photon energies above 2 keV with HEAO 1, ASCA, and Chandra,…
A Quantitative Comparison of the Small Magellanic Cloud, Large Magellanic Cloud, and Milky Way Ultraviolet to Near-Infrared Extinction Curves
Gordon, Karl D.; Clayton, Geoffrey C.; Misselt, K. A. +2 more
We present an exhaustive quantitative comparison of all the known extinction curves in the Small and Large Magellanic Clouds (SMC and LMC) with our understanding of the general behavior of Milky Way extinction curves. The RV-dependent CCM relationship of Cardelli, Clayton, and Mathis and the sample of extinction curves used to derive th…
The Galactic Disk Mass Function: Reconciliation of the Hubble Space Telescope and Nearby Determinations
Chabrier, Gilles
We derive and parameterize the Galactic mass function (MF) below 1 Msolar characteristic of both single objects and binary systems. We resolve the long-standing discrepancy between the MFs derived from the Hubble Space Telescope (HST) and from the nearby luminosity functions, respectively. We show that this discrepancy stemmed from two …
Estimating Star Formation Rates from Infrared and Radio Luminosities: The Origin of the Radio-Infrared Correlation
Bell, Eric F.
I have assembled a diverse sample of galaxies from the literature with far-ultraviolet (FUV), optical, infrared (IR), and radio luminosities to explore the calibration of radio-derived and IR-derived star formation (SF) rates and the origin of the radio-IR correlation. By comparing the 8-1000 µm IR, which samples dust-reprocessed starlight, …