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The O II Luminosity Density of the Universe
Hogg, David W.; Cohen, Judith G.; Blandford, Roger +1 more
Equivalent widths of [O II] 3727 Å lines are measured in 375 faint galaxy spectra taken as part of the Caltech Faint Galaxy Redshift Survey centered on the Hubble Deep Field. The sensitivity of the survey spectra to the [O II] line is computed as a function of magnitude, color, and redshift. The luminosity function of galaxies in the [O II] line, …
Infrared Space Observatory Measurements of a [C II] 158 Micron Line Deficit in Ultraluminous Infrared Galaxies
Wolfire, M. G.; Lord, S. D.; Stacey, G. J. +6 more
We report measurements of the [C II] 157.74 µm fine-structure line in a sample of seven ultraluminous infrared galaxies (ULIGs) (LIR>1012 Lsolar) with the Long Wavelength Spectrometer on the Infrared Space Observatory. The [C II] line is an important coolant in galaxies and arises in interstellar gas expos…
An analytic solar magnetic field model
McKenzie, J. F.; Banaszkiewicz, M.; Axford, W. I.
We describe a simple analytic model for the magnetic field in the solar corona and interplanetary space which is appropriate to solar minimum conditions. The model combines an azimuthal current sheet in the equatorial plane with an axisymmetric multipole field representing the internal magnetic field of the Sun. The radial component of the field f…
The Hubble Space Telescope Quasar Absorption Line Key Project. XIV. The Evolution of Lyα Absorption Lines in the Redshift Interval z = 0-1.5
Turnshek, David A.; Schneider, Donald P.; Savage, Blair D. +10 more
We present the results of an analysis of the rate of evolution of the Lyα absorption lines in the redshift interval 0.0 to ~1.5 based upon a sample of 987 Lyα absorption lines identified in the spectra of 63 QSOs obtained with the Faint Object Spectrograph (FOS) of the Hubble Space Telescope (HST). These spectra were obtained as part of the QSO Ab…
Measurements of Solar Magnetic Element Motion from High-Resolution Filtergrams
Berger, Thomas E.; Title, Alan M.; Löfdahl, Mats G. +1 more
Solar photospheric flowfield properties on sub-0.5" scales are measured using local correlation tracking (LCT) and object tracking of magnetic bright points (MBPs: photospheric bright points associated with magnetic elements). The dataset is a 70 minute time series of cospatial and cotemporal G-band 4305 Å and wideband 4686 Å filtergrams obtained …
Binary Stars in the Orion Trapezium Cluster Core
Beckwith, Steven V. W.; Petr, Monika G.; Coudé du Foresto, Vincent +2 more
We have obtained high angular resolution (0.13" FWHM) near-infrared images of the central ~40" × 40" of the Trapezium cluster, using a speckle holography technique that we describe in detail. A search for close binary systems was made in Ks (2.16 µm) and H (1.65 µm) mosaic images, in which 45 and 35 stars were detected, resp…
The absolute magnitudes of RR Lyraes from HIPPARCOS parallaxes and proper motions
Garrido, R.; Evans, D. W.; Solano, E. +5 more
We have used HIPPARCOS proper motions and the method of Statistical Parallax to estimate the absolute magnitude of RR Lyrae stars. In addition we used the HIPPARCOS parallax of RR Lyrae itself to determine it's absolute magnitude. These two results are in excellent agreement with each other and give a zero-point for the RR Lyrae M_v,[Fe/H] relatio…
Galaxy-Galaxy Lensing in the Hubble Deep Field: The Halo Tully-Fisher Relation at Intermediate Redshift
Gwyn, Stephen D. J.; Hudson, Michael J.; Dahle, Håkon +1 more
A tangential distortion of background source galaxies around foreground lens galaxies in the Hubble Deep Field is detected at the 99.3% confidence level. An important element of our analysis is the use of photometric redshifts to determine distances of lens and source galaxies and rest-frame B-band luminosities of the lens galaxies. The lens galax…
The Relationship between Galaxies and Low-Redshift Weak Lyα Absorbers in the Directions of H1821+643 and PG 1116+215
Tripp, Todd M.; Savage, Blair D.; Lu, Limin
To study the nature of low-z Lyα absorbers in the spectra of QSOs, we have obtained high signal-to-noise ratio (S/N) UV spectra of H1821+643 (zem = 0.297) and PG 1116+215 (zem = 0.177) with the Goddard High-Resolution Spectrograph on the Hubble Space Telescope. The spectra have minimum S/Ns of ~70-100 and 3 σ limiting equival…
The Distance to the Large Magellanic Cloud from the Eclipsing Binary HV 2274
Ribas, I.; Fitzpatrick, E. L.; Guinan, E. F. +6 more
The distance to the Large Magellanic Cloud (LMC) is crucial for the calibration of the cosmic distance scale. We derive a distance to the LMC based on an analysis of ground-based photometry and Hubble Space Telescope (HST)-based spectroscopy and spectrophotometry of the LMC-eclipsing binary system HV 2274. Analysis of the optical light curve and t…