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Determination of Distances to Galaxies of the NGC 1023 Group. The Hubble Constant

Tikhonov, N. A.; Galazoutdinova, O. A.

On the basis of photographs from the 6 m Large Azimuthal Telescope and the Hubble Space Telescope, VRI photometry of stars in 11 galaxies in the NGC 1023 group has been carried out. The distances to these galaxies were determined by the method of brightest stars. The distances to NGC 925 and NGC 1023 were determined from the position of the top of…

New Observations of the High-Velocity Outflows of the Proto-Planetary Nebula Hen 3-1475

García-Lario, P.; Riera, A.; Manchado, A. +2 more

The proto-planetary nebula Hen 3-1475 shows a remarkable highly collimated optical jet with a S-shaped string of shock-excited knots. Moreover, extremely high velocities have been observed in the innermost regions of its jet. We present a detailed analysis of the kinematic structure, and the excitation conditions in the shock-excited knots based o…

An HST emission-line imaging survey of 3CR radio galaxies

Sparks, W. B.; Macchetto, F.; McCarthy, P. J. +4 more

We present narrow-band images of sixty-four 3CR radio sources observed in lines of [OII] 3727 Å, [OIII] 5007 Å, and H α using the WFPC2 camera on-board HST. The images reveal a wide variety of emission lime morphologies, from compact nuclear regions to large-scale emission knots, filaments, and spiral-like structures. Many objects give evidence of…

The O⁺ and O⁺⁺ emission lines near 834 Å in the quiet sun solar spectrum

Doschek, G. A.

I present quiet Sun solar disk averaged emission line intensities (at the Earth) and the full widths at half maximum intensity (FWHM) for the O⁺ and O⁺⁺ emission lines that fall near 834 Å. These lines are important as excitation sources for O⁺ and O⁺⁺ emission in the Earth's upper ionosphere, plasmasphe…

Star Formation and Dust Extinction in Nearby Star Forming and Starburst Galaxies

Buat, Veronique

We study the star formation rate and dust extinction properties of a sample of nearby star forming galaxies as derived from Halpha and UV (2000 A) observations and we compare them to those of a sample of starburst galaxies. The dust extinction in Halpha is estimated from the Balmer decrement and the extinction in UV using the FIR to UV flux ratio …

Cosmic ray intensity variation during a CME

Kandemir, G.; Geçkinli, M.; Firat, C. +2 more

The June 6, 2000 coronal mass ejection was an exceptional full halo, which made it possible to measure cosmic ray (CR) decrease with a simple experimental set-up. Variation in the local secondary cosmic ray density has been investigated by means of gamma rays. The experiment site was located in Istanbul (41.1N, 29.0E). CR electrons and slow gamma …

New views of the solar transition region

Peter, Hardi

Two decades ago it was discovered that emission lines from the solar transition region from the chromosphere to the corona are composed by two Gaussian components: a narrow core and a broad second component contributing up to 25% to the total intensity. New observations with SUMER/SOHO allow for the first time statistically significant results on …

The multiple frequencies of the delta Scuti star V350 Peg

García-Melendo, E.; Lampens, P.; Vidal-Sáinz, J. +1 more

V350 Peg is a delta Scuti star discovered by Hipparcos (ESA \cite{esa97}). During 35 nights between July 1997 and December 2001 some 7500 CCD V observations were acquired at the Monegrillo and Esteve Duran observatories in Spain. The new data show that this star pulsates in a close doublet of frequencies separated by 0.17 c/d (Delta f/f=3%) with s…

SOHO/EPHIN observation of a multiple large solar energetic particles event in November 1997

Kunow, H.; Gómez-Herrero, R.; Müller-Mellin, R. +2 more

In November 1997, EPHIN (Electron, Proton, Helium INstrument) on board Solar and Heliospheric Observatory (SOHO ) detected solar energetic particles (SEP) from a multiple large event. Composition, temporal profiles and energy spectra of electrons, hydrogen and helium have been analyzed. The SEP events show, in general, gradual characteristics rela…

IUE observations of beta Cephei stars. Paper 1: BW Vulpeculae

Stickland, D. J.; Lloyd, C.