Search Publications
The Radio-Optical Jet in NGC 3862 from Parsec to Subkiloparsec Scales
Venturi, T.; O'Dea, C. P.; Giovannini, G. +4 more
We have observed the radio source in NGC 3862 (3C 264) simultaneously with the European VLBI network and the MERLIN arrays, obtaining detailed images of its radio structure from parsec to subkiloparsec scales. 3C 264 shows a one-sided jet with evident variations in its morphological properties with distance. We have analyzed Hubble Space Telescope…
NICMOS Observations of the Pre-Main-Sequence Planetary Debris System HD 98800
Schneider, Glenn; Hines, Dean C.; Low, Frank J.
Spectral energy distributions (SEDs) from 0.4 to 4.7 µm are presented for the two principal stellar components of HD 98800, A and B. The third major component, an extensive planetary debris system (PDS), emits greater than 20% of the luminosity of star B in a blackbody SED at 164+/-5 K extending from mid-IR to millimeter wavelengths. At 0.95…
Far-Ultraviolet Space Telescope Imaging Spectrograph Spectra of the White Dwarf REJ 1032+532. II. Stellar Spectrum
Green, E. M.; Barstow, M. A.; Bruhweiler, F. C. +2 more
We discuss the Hubble Space Telescope Space Telescope Imaging Spectrograph UV echelle spectrum of the hot DA white dwarf REJ 1032+532. The interstellar data from this spectrum are presented by Holberg and coworkers. In this paper we discuss a number of strong photospheric features due to C, N, and Si that are present in the REJ 1032+532 spectrum. …
Probable Detection of a Bright Infrared Coronal Emission Line of Si IX near 3.93 Microns
Lin, H.; Mann, I.; Kuhn, J. R. +7 more
We report here the probable detection of an emission line of Si IX that was observed from an open C130 aircraft over the Pacific Ocean during the 1998 total solar eclipse. Although the IR data themselves are inconclusive because of the uncertainty in the precise central wavelengths of the narrowband filters during the eclipse, the consistency of t…
Hubble Space Telescope/Faint Object Spectrograph Spectroscopy of Spatially Resolved Narrow-Line Regions in the Seyfert 2 Galaxies NGC 2110 and NGC 5929
Simpson, Chris; Mulchaey, John S.; Ferruit, Pierre +3 more
We present the results of UV and optical Hubble Space Telescope/Faint Object Spectrograph spectroscopy of bright, extranuclear regions of line emission in the Seyfert galaxies NGC 2110 and NGC 5929. We have obtained spectra of the brightest region of the ``nuclear jet'' of NGC 2110 (75 pc from the nucleus) and of the southwest emission-line cloud …
Tomographic Separation of Composite Spectra. VI. The Physical Properties of the Massive Close Binary HD 152248
Gies, Douglas R.; Penny, Laura R.; Bagnuolo, William G., Jr.
We present the results of a Doppler tomographic reconstruction of the UV spectra of the double-lined O binary HD 152248 based on observations made with IUE. We used cross-correlation methods to obtain radial velocities, confirm the orbital elements, estimate the UV flux ratio, and determine projected rotational velocities. The individual component…
X-Ray Observations of the Seyfert Galaxy LB 1727 (1H 0419-577)
Nandra, K.; Turner, T. J.; Kraemer, S. B. +6 more
We discuss the properties of the Seyfert 1.5 galaxy LB 1727, also known as 1H 0419-577, from X-ray observations obtained by ASCA and ROSAT, along with optical observations from earlier epochs. The source flux was F2-10~=10-11 ergs cm-2 s-1 during the ASCA observations that were carried out during 1996 Ju…
No Increase of the Red Giant Branch Tip Luminosity toward the Center of M31
Meynet, G.; Jablonka, P.; Sarajedini, A. +3 more
We present observations with the Hubble Space Telescope Wide-Field Planetary Camera 2 of three fields centered on super-metal-rich globular clusters in the bulge of M31. Our (I, V-I) color-magnitude diagrams reach as faint as I~26.5 mag and clearly reveal the magnitude of the first-ascent red giant branch (RGB) tip. We find that the apparent I mag…
The Quasar Pair Q1634+267A,B and the Binary QSO versus Dark Lens Hypotheses
Peng, C. Y.; Keeton, C. R.; Kochanek, C. S. +6 more
Deep HST/NICMOS H-band (F160W) observations of the z=1.96 quasar pair Q1634+267A and B reveal no signs of a lens galaxy to a 1 σ threshold of ~=22.5 mag. The minimum luminosity for a normal lens galaxy would be a 6L* galaxy at z~=0.5, which is 650 times greater than our detection threshold. Our observation constrains the infrared mass-to-light rat…
Characteristic Scales of Photospheric Flows and Their Magnetic and Temperature Markers
Lawrence, J. K.; Cadavid, A. C.; Ruzmaikin, A. A.
We study the characteristic scales of quiet-Sun photospheric velocity fields along with their temperature and magnetic markers in Doppler images from the Michelson Doppler Imager aboard the SOHO satellite (SOHO/MDI) in simultaneous, Doppler, magnetic, and intensity images from the San Fernando Observatory and in full-disk magnetograms and an inten…