Search Publications

Observational Constraints on Models of the Solar Background Spectrum

Fleck, B.; Jefferies, S. M.; Tarbell, T. +3 more

We discuss the properties of the solar background signal as observed in high-quality, l-ν power and phase difference spectra of the continuum (C), velocity (V), and line intensity (I) fluctuations of the Ni I 6768 Å line. These spectra were generated from high-resolution images acquired by the Michelson Doppler Imager on board SOHO.

We confir…

The H⁺₃ Latitudinal Profile of Saturn

Ballester, Gilda E.; Miller, Steve; Stallard, Tom +3 more

We present an H⁺₃ latitudinal profile of Saturn, obtained in 1998 October using the CSHELL spectrometer on the NASA Infrared Telescope Facility. The profile, measured at 3.953 µm, shows that the majority of the emission is concentrated in the auroral ovals, making Saturn similar to Jupiter and different from Uranus. The…

The C IV Absorption-Mg II Kinematics Connection in <Z> ~ 0.7 Galaxies

Charlton, Jane C.; Schneider, Donald P.; Steidel, Charles C. +4 more

We have examined Faint Object Spectrograph data from the Hubble Space Telescope archive for C IV λλ1548, 1550 absorption associated with 40 Mg II λλ2796, 2803 absorption-selected galaxies at 0.4<=z<=1.4. We report a strong correlation between Mg II kinematics, measured in ~6 km s^-1 resolution HIRES/Keck spectra, and W_r(…

Hubble Space Telescope Faint Object Camera Spectroscopy of the Narrow-Line Region of NGC 4151. I. Gas Kinematics

Axon, David J.; Marconi, A.; Macchetto, F. D. +2 more

We present the results from a detailed kinematic analysis of both ground-based, and Hubble Space Telescope (HST)/Faint Object Camera long-slit spectroscopy at subarcsecond spatial resolution of the narrow-line region (NLR) of NGC 4151. In agreement with previous work, the extended emission gas (R>4") is found to be in normal rotation in the gal…

Chromatic Holography of the Sunspot Acoustic Environment

Braun, D. C.; Lindsey, C.

We use helioseismic holography to obtain seismic images of a sunspot and its local environment over the 3-8 mHz acoustic spectrum. We are particularly interested in the acoustic deficit brought about by strong acoustic absorption by the sunspot itself in the 3-4 mHz range and in the helioseismic character of the ``acoustic moat'' recently discover…

Kinematic Measurements of Polar Jets Observed by the Large-Angle Spectrometric Coronagraph

Howard, R. A.; Wood, B. E.; Karovska, M. +2 more

We analyze polar jets observed by the Large-Angle Spectrometric Coronagraph (LASCO) instrument aboard the Solar and Heliospheric Observatory. The events studied here are from 1997 March 24 and August 5. The main objective of our analysis is to determine whether the jets' motions are consistent with ballistic behavior. Although ballistic trajectori…

The Lyα Forest of the Quasar in the Hubble Deep Field South

Ferguson, H. C.; Carollo, C. M.; Stiavelli, M. +8 more

The quasar in the Hubble Deep Field South (HDF-S), J2233-606 (z_em=2.23), has been observed exhaustively by ground-based telescopes and by the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope at low, medium, and high resolution in the spectral interval from 1120 to 10000 Å. The combined data give continuous covera…

The Magnetic Association of Coronal Bright Points

Preś , Paweł; Phillips, Kenneth H. J.

Several coronal bright points identified in a quiet region of the Sun from Solar and Heliospheric Observatory/Extreme-Ultraviolet Imaging Telescope Fe XII images are found to have a time evolution from birth to decay that is extremely well correlated with the rise and fall of magnetic flux as determined from photospheric magnetograms made with the…

Discovery of a Remarkable Point-Symmetric Proto-Planetary Nebula: Hubble Space Telescope Imaging of IRAS 04296+3429

Sahai, Raghvendra

We present images of the proto-planetary nebula (PPN) IRAS 04296+3429 (hereafter I04296) taken with the Hubble Space Telescope Wide Field Planetary Camera 2 in two wide-band filters centered at 0.56 and 0.81 µm. We find that this object, which belongs to a class of carbon-rich PPNs with a peculiar 21 µm dust emission feature, has a str…

The Morphologically Divided Redshift Distribution of Faint Galaxies

Green, Richard F.; Im, Myungshin; Roche, Nathan +4 more

We have constructed a morphologically divided redshift distribution of faint field galaxies using a statistically unbiased sample of 196 galaxies brighter than I=21.5 for which detailed morphological information (from the Hubble Space Telescope) as well as ground-based spectroscopic redshifts are available. Galaxies are classified into three rough…