Search Publications
The Abundance of Boron in Three Halo Stars
Lambert, David L.; Lemke, Michael; Duncan, Douglas K.
B abundances for three halo stars: HD 140283, HD 19445, and HD 201891 are presented. Using recent determinations of the Be abundance in HD 140283, B/Be of 10 +5/-4 is found for this star, and similar ratios are inferred for HD 19445 and HD 201891. This ratio is equal to the minimum value of 10 expected from a synthesis of B and Be by high-energy c…
Ultraviolet Observations of the Gas Phase Abundances in the Diffuse Clouds toward zeta Ophiuchi at 3.5 Kilometers per Second Resolution
Savage, Blair D.; Sofia, Ulysses J.; Cardelli, Jason A.
Goddard High Resolution Spectrograph echelle mode measurements at 3.5 km/s resolution are presented for interstellar absorption produced by C II, O I, Mg I, Mg II, Al III, P II, Cr II, Mn II, Fe II, Ni II, Cu II, Zn II, Ga II, Ge II, and Kr I. The absorption line measurements are converted into representations of apparent column density per unit v…
The Cepheid Distance to IC 4182: Calibration of M V(max) for SN IA 1937C and the Value of H 0
Saha, A.; Panagia, Nino; Sandage, Allan +2 more
Cepheid variables with periods from 2 to more than 50 days have been found in IC 4182 from observations with the Hubble Space Telescope over a time interval of 47 days, comprised of 20 epochs. The period-luminosity relation from photometry of 27 Cepheids in the F555W HST magnitude system gives an apparent V distance modulus of (m - M)_AV_ = 28.47 …
Hubble Space Telescope Faint Object Spectrograph and Ground-based Observations of the Broad Absorption Line Quasar 0226-1024
Turnshek, David A.; Burbidge, E. M.; Morris, Simon L. +6 more
Faint Object spectrograph data from the Hubble Space Telescope of the broad absorption line quasar 0226 - 1024 have revealed the presence of 8-10 absorbing ions between 680 and 1000 A (restframe): C III, N III, N IV, O III, O IV, O VI, S V, S VI, possibly Ne VIII, and possibly O V^*^ arising from a metastable excited state. We also present ground-…
Evolving, Dynamical Models for Collapsed-Core Globular Clusters: M15 and NGC 6624
Cohn, Haldan N.; Lugger, Phyllis M.; Murphy, Brian W. +1 more
The stellar populations of the collapsed-core globular clusters M15 and NGC 6624 are investigated by fitting observed surface-brightness and projected velocity-dispersion profiles. The present evolving cluster models were generated by the direct Fokker-Planck method and incorporate realistic stellar mass spectra and energy input from binaries form…
Fractionation of CO in the Diffuse Clouds toward zeta Ophiuchi
Federman, S. R.; Lambert, David L.; Cardelli, Jason A. +1 more
An analysis of CO A-X bands in diffuse clouds toward Zeta Ophiuchi is presented. The results provide isotopic ratios that constitute the strongest observational evidence for highly localized isotopic fractionation of CO in diffuse portions of an interstellar cloud. The value of the fractionation implies that selective photodissociation is the cont…
The Snapshot Survey: A Search for Gravitationally Lensed Quasars with the Hubble Space Telescope
Maoz, D.; Lahav, O.; Schneider, D. P. +4 more
In a systematic attempt to find new examples of multiply imaged quasars that are the result of gravitational lensing, 89 short exposures, through two filters, of high-luminosity quasars from a well-defined sample have been obtained with the Hubble Space Telecope's Planetary Camera. Useful high-resolution images of approximately 30 quasars have res…
Hubble Space Telescope Imaging of Distant Galaxies: 4C 41.17 at Z = 3.8
Chambers, K. C.; Macchetto, F.; Miley, G. K. +1 more
The Hubble Space telescope has been used to image the continuum emission from 4C 41.17 at z = 3.8, the most distant galaxy known. The galaxy was detected with good signal-to-noise ratio and was spatially resolved at the 0.1" (440 pc) HST resolution. The measured integrated flux density is in good agreement with the ground-based value (R~22). About…
Preliminary Analysis of an Ultraviolet Hubble Space Telescope Faint Object Camera Image of the Center of M31
Boksenberg, A.; Barbieri, C.; Weigelt, G. +17 more
A 5161 s exposure was taken with the FOC on the central 44" of M31, through a filter centered at 1750 A. Much of the light is redleak from visible wavelengths, but nearly half of it is genuine UV. The image shows the same central peak found earlier by Stratoscope, with a somewhat steeper dropoff outside that peak. More than 100 individual objects …
The Ultraviolet Absorption Spectrum of the Quasar H1821+643 (z = 0.297)
Schneider, Donald P.; Green, Richard F.; Jannuzi, Buell T. +2 more
We report measurements of the absorption lines in the ultraviolet spectrum of the nearby luminous quasar H1821+643 (z = 0.297). The results were obtained using high-resolution observations with the faint object spectrograph of the Hubble Space Telescope. A total of 51 absorption lines and a number of emission features were detected between 1190 an…