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A Possible Evolutionary Connection between Active Galactic Nuclei and Starbursts in LINERS
Zheng, W.; Lei, S. J.; Huang, J. H. +2 more
Our analysis of the two magnitude-limited samples of LINERs suggests a correlation between LFIR/LB, or f(25 µm)/f(60 µm), and Hubble-type index at greater than 99.99% significance level. As LFIR/LB and f(25 µm)/f(60 µm) are considered to be indicators of star formation activity an…
The δ Scuti Star DK Virginis (HR 5005) Revisited
Pamyatnykh, A. A.; Jerzykiewicz, Mikołaj
An analysis of Hp photometry of DK Virginis is carried out. The analysis reveals two frequencies, f1=9.2095 and f2=7.5764 cycles day-1. These values turn out to be good enough to bridge the gap between the two available series of ground-based data, obtained in 1973 and 1980, so that the frequencies can be refined. …
Solar rotation in the subphotospheric layers
González Hernández, I.; Patrón, J.
The solar rotation rate at latitudes 0°, 15° and 30° has been inferred by averaging the results of 120 regions of 15°×15°, which have been studied over a total area of about 75° in latitude and 360° in longitude. A local helioseismology technique, the ring diagram analysis method, has been used to analyse the horizontal velocity vectors from about…
Transition region and coronal structuring
Mathioudakis, M.; Keenan, F. P.; Phillips, K. J. H. +3 more
In this paper we examine regions of internetwork, network and bright network emission, observed in the quiet Sun with the Coronal Diagnostic Spectrometer (cds) onboard SoHO. The slopes of the emission measure distributions, between 5.4 <= log Te <= 6.0, are found to differ in each region, suggesting the presence of different atmos…
HST High-Resolution Backscatter Image of Saturn's G Ring
French, Richard G.; Lissauer, Jack J.
On 14 October 1996, we imaged Saturn's faint G ring with the Hubble Space Telescope's WFPC2 Planetary Camera. This is the highest resolution image of the G ring ever obtained in backscattered light, with an image scale of only 282 km per pixel. The 400-s exposure was taken using the F555W filter at a solar phase angle of α=1.93° and a ring tilt of…
Ultraviolet Spectral Variability and the Lyα Forest in the Lensed Quasar Q0957+561
Michalitsianos, A. G.; Dolan, J. F.; Hill, R. J. +1 more
Far-ultraviolet spectra of the gravitational lens components Q0957+561A, B were obtained with the Hubble Space Telescope Faint Object Spectrograph (FOS) at five equally spaced epochs, one every 2 weeks. We confirm the flux variability of the quasar's Lyα and O VI λ1037 emission lines in IUE spectra reported in earlier work of Dolan et al. The flux…
Hβ photometry of southern CP2 stars: is the uvbybeta luminosity calibration also valid for peculiar stars?
Vogt, N.; Paunzen, E.; Maitzen, H. M. +1 more
We present Hβ photometry of 233 southern CP2 stars (covering the magnetic Ap stars according to the definition by Preston 1974) brighter than V < 8.5 mag from the list of Bidelman & MacConnell (1973). Absolute magnitudes derived from this photometry together with already existing uvby photometry is confronted with Hipparcos results availabl…
Physical parameters of EUV explosive events
Doyle, J. G.; Pérez, M. E.
Previously published results of EUV explosive events and electron density enhancements in the solar transition region are revised. An attempt has been made to correlate both observational phenomena, and to associate the observed density enhancements to magnetic reconnection sites. The corresponding local magnetic field strength in these sites is e…
The ISOCAM/LW Detector Dark Current Behaviour
Okumura, K.; Sauvage, M.; Biviano, A. +5 more
We describe the calibration, measurements and data reduction, of the dark current of the ISOCAM/LW detector. We point-out the existence of two significant drifts of the LW dark-current, one throughout the ISO mission, on a timescale of days, another within each single revolution, on a timescale of hours. We also show the existence of a dependence …
Nonthermal Flare Emission from MEV-Energy Electrons at 17, 34, and 86 GHZ
Kundu, M. R.; White, S. M.; Shibasaki, K. +1 more
We present analyses of two solar flares observed with high spatial resolution at 86 GHz with the BIMA millimeter-wavelength telescope and at 17 and 34 GHz with the Nobeyama radioheliograph. The flares were observed on 1998 November 24 and 1999 May 1. At millimeter wavelengths these are impulsive events, and therefore they must be produced by MeV-e…