Search Publications
Missions
Journals
Publication Years
Ultraviolet Hubble Space Telescope Snapshot Survey of 3CR Radio Source Counterparts at Low Redshift
Baum, Stefi A.; O'Dea, Christopher P.; Sparks, William B. +6 more
We present UV images of 27 3CR radio galaxies with redshifts z<0.1 that have been imaged with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). The observations employed the NUV MAMA and broadband filters with peak sensitivity at 2200 Å. We find that the UV luminosities show approximately a factor of 10-…
The Most Violent Super-Active Regions in the 22nd and 23rd Cycles
Liu, Yang; Tian, Lirong; Wang, Jinxiu
We survey 14 super-active regions (SARs) in the 22nd cycle and 15 SARs in the 23rd cycle. Each produced major flares and major solar storms. Among them, the 25 most violent super active regions (VSARs) are selected based on five parameters: the largest area of sunspots, X-ray flare index (XRI), 10.7 cm radio flux, proton flux and geomagnetic A
Determination of Hyperfine-Induced Transition Rates from Observations of a Planetary Nebula
Judge, Philip G.; Proffitt, Charles R.; Brage, Tomas
Observations of the planetary nebula NGC3918 made with the STIS instrument on the Hubble Space Telescope reveal the first unambiguous detection of a hyperfine-induced transition 2s2p
3Po0→2s2
1S0 in the berylliumlike emission line spectrum of N IV at 1487.89Å. …
Non-LTE Calculation of the Ni I 676.8 Nanometer Line in a Flaring Atmosphere
Qiu, Jiong; Wang, Haimin; Ding, M. D.
The Ni I 676.8 nm line is used by the Solar and Heliospheric Observatory Michelson Doppler Imager to measure the magnetic field and velocity field in the solar atmosphere. We make non-LTE calculations of this line in an atmosphere that is bombarded by an energetic electron beam. This case is associated with the occurrence of solar flares. The elec…
The time variation in infrared water-vapour bands in Mira variables
Onaka, T.; Murakami, H.; Yamamura, I. +2 more
The time variation in the water-vapour bands in oxygen-rich Mira variables has been investigated using multi-epoch ISO/SWS spectra of four Mira variables in the 2.5-4.0 mu m region. All four stars show H2O bands in absorption around minimum in the visual light curve. At maximum, H2O emission features appear in the ~ 3.5-4.0 m…
Velocity-resolved [Fe II] Line Spectroscopy of L1551 IRS 5: A Partially Ionized Wind under Collimation around an Ionized Fast Jet
Kobayashi, Naoto; Tokunaga, Alan T.; Terada, Hiroshi +5 more
We present a new [Fe II] λ1.644 µm emission-line image of the L1551 IRS 5 jets and a velocity-resolved spectrum obtained with the Subaru Telescope. In the [Fe II] line image showing two separate jetlike features, a strong and spatially wide [Fe II] emission feature was found elongated along the northern jet at its base. The echelle spectrum …
The HST survey of the B2 sample of radio-galaxies: Optical nuclei and the FR I/BL Lac unified scheme
Capetti, A.; Morganti, R.; Chiaberge, M. +4 more
We examine the optical properties of the nuclei of low luminosity radio-galaxies using snapshot HST images of the B2 sample. In agreement with the results obtained from the analysis of the brighter 3C/FR I sample, we find a correlation between fluxes (and luminosities) of the optical and radio cores. This provides further support for the interpret…
NGC 4314. IV. Photometry of Star Clusters with the Hubble Space Telescope: History of Star Formation in the Vicinity of a Nuclear Ring
Smith, Beverly J.; Jørgensen, Inger; Kenney, Jeffrey D. P. +2 more
Using Hubble Space Telescope (HST) WFPC2 images, we have obtained U, B, V, I, and Hα photometry for 76 star clusters in the nuclear star-forming ring of the barred spiral galaxy NGC 4314. These clusters are likely associated with an inner inner Lindblad resonance (IILR). The blue colors and Hα emission for most of these clusters imply very young a…
Structural Parameters and Dynamical Masses for Globular Clusters in M33
Brodie, Jean P.; Huchra, John P.; Sarajedini, Ata +1 more
Using high-dispersion spectra from the HIRES echelle spectrograph on the Keck I telescope, we measure velocity dispersions for four globular clusters (GCs) in M33. Combining the velocity dispersions with integrated photometry and structural parameters derived from King-Michie model fits to Wide Field Planetary Camera 2 images, we obtain mass-to-li…
X-Ray and Optical Variations in the Classical Be Star γ Cassiopeia: The Discovery of a Possible Magnetic Dynamo
Smith, Myron A.; Henry, Gregory W.; Robinson, Richard D.
The classical B0.5e star γ Cassiopeia is known to be a unique X-ray source by virtue of its moderate LX (1033 ergs s-1), hard X-ray spectrum, and light curve punctuated by ubiquitous flares and slow undulations. The peculiarities of this star have led to a controversy concerning the origin of these emissions: wheth…