Search Publications
NICMOS Imaging of Molecular Hydrogen Emission in Seyfert Galaxies
Rieke, G. H.; Alonso-Herrero, A.; Quillen, A. C. +3 more
We present near-infrared (NICMOS) imaging of broadband and molecular hydrogen emission in Seyfert galaxies. In six of 10 Seyfert galaxies we detect resolved or extended emission in the 1-0 S(1) 2.121 µm or 1-0 S(3) 1.9570 µm molecular hydrogen lines. We did not detect emission in the most distant galaxy or in two Seyfert 1 galaxies bec…
The Excitation Mechanism of Emission-Line Regions in Seyfert Galaxies
Tsvetanov, Zlatan; Koratkar, Anuradha; Dopita, Michael +2 more
We present Hubble Space Telescope UV/optical spectrophotometry and ground-based optical spectrophotometry of the brightest knots in the emission-line regions of the Seyfert galaxies NGC 5643 and NGC 5728. These objects have ionization cones, radio and soft X-ray emission, and evidence of nuclear outflows and winds, suggesting that shocks may be as…
Phase Differences and Gains between Intensity and Velocity in Low-Degree Acoustic Modes Measured by SOHO
Jiménez, Antonio; Severino, Giuseppe; Roca Cortés, Teodoro +1 more
Helioseismic instruments aboard SOHO are making possible a more accurate way of investigating the internal structure of the Sun. Making use of the different techniques and characteristics of these instruments, it is possible to measure solar oscillations as variations of the photospheric velocity (GOLF, MDI) or as irradiance and radiance fluctuati…
Interpreting the Solar Limb Shape Distortions
Armstrong, James; Kuhn, J. R.
Accurate measurements of the solar oblateness have recently been obtained from the SOHO/MDI satellite experiment. The new data are sufficiently accurate to measure nonnegligible multipole shape terms of higher order than the oblateness. Here we extend earlier solar limb shape calculations and compare the new data with the helioseismic evidence for…
Detection of H2 Pure Rotational Line Emission from the GG Tauri Binary System
van Dishoeck, Ewine F.; Blake, Geoffrey A.; Hogerheijde, Michiel R. +2 more
We present the first detection of the low-lying pure rotational emission lines of H2 from circumstellar disks around T Tauri stars, using the Short Wavelength Spectrometer on the Infrared Space Observatory. These lines provide a direct measure of the total amount of warm molecular gas in disks. The J=2-->0 S(0) line at 28.218 µ…
Goddard High-Resolution Spectrograph Observations of the B III Resonance Doublet in Early B Stars: Abundances and Isotope Ratios
Wahlgren, Glenn M.; Proffitt, Charles R.; Jönsson, Per +2 more
Boron abundances and isotope ratios in two early B stars have been measured by using the Hubble Space Telescope's Goddard High-Resolution Spectrograph (GHRS) in order to observe the B III resonance doublet near 2066 Å. We also report new experimental and theoretical results for the wavelengths, isotope shift, and hyperfine structure of these boron…
Stellar Masses, Kinematics, and White Dwarf Composition for Three Close DA+DME Binaries
Vennes, Stéphane; Thorstensen, John R.; Polomski, Elisha F.
We determine the mass functions and mass ratios for three close white dwarf plus red dwarf binaries (EUVE J0720-317, 1016-053, and 2013+400). Hubble Space Telescope Goddard High-Resolution Spectrograph spectra of the He II λ1640 and C IV λ1550 spectral lines trace the white dwarf orbital motion, and Hamilton Spectrograph echelle spectra (Lick Obse…
The Starburst-Active Galactic Nucleus Connection in Active Galaxies: The MassiveNuclear Star-Forming Disk in NGC 4303
Colina, L.; Arribas, S.
Two-dimensional spectroscopy of the low-redshift active galaxy NGC 4303 obtained with the Two-Dimensional Fiber ISIS System is presented. The ionization structure and velocity field of the nuclear region of this galaxy, where a compact UV-bright spiral structure connected with the UV-bright core has been detected with the Hubble Space Telescope (H…
A NICMOS Search for High-Redshift Elliptical Galaxy Candidates
Stiavelli, Massimo; Treu, Tommaso
We have collected optical follow-up observations from the ground and the Hubble Space Telescope (HST) for 13.74 arcmin2 of archival images taken with the HST Near-Infrared Camera and Multiobject Spectrograph (NICMOS). We use two criteria to select E/S0 galaxy candidates at z>~1 and z>~1.5 (high-redshift elliptical candidates [HizE…
Hubble Space Telescope Faint Object Spectrograph Optical and Ultraviolet Spectroscopy of the Bow Shock HH 47A
Hartigan, Patrick; Raymond, John; Tumlinson, Jason +2 more
We present new spectra obtained with the Faint Object Spectrograph aboard the Hubble Space Telescope of the HH 47A bow shock and Mach disk that cover the entire spectral range between λλ2220 and 6810. In addition to emission lines seen previously from HH objects, we uncover over a dozen weak Fe IItransitions in the ultraviolet. The flux ratios bet…