Search Publications
The Accretion Disk and White Dwarf in the Short-Period Dwarf Novae TY Piscium and V436 Centauri during Quiescence
Sion, Edward M.; Nadalin, Ira
The short-period dwarf novae TY Psc and V436 Cen are SU UMa systems with very similar orbital periods, similar recurrence times for normal outbursts (~23 days) and superoutbursts (~340 days), and nearly identical outburst amplitudes. We have carried out high-gravity model atmosphere and accretion disk synthetic spectra from the grid of Wade & …
Millimeter observations of radio-loud active galaxies
Bertoldi, F.; van Bemmel, I. M.
In order to study the nature of the far-infrared emission observed in radio-loud active galaxies, we have obtained 1.2 mm observations with the IRAM 30 m telescope for a sample of eight radio-loud active galaxies. In all objects we find that the 1.2 mm emission is dominated by non-thermal emission. An extrapolation of the non-thermal radio spectru…
Eclipsing Broad Emission Lines in Hercules X-1: Evidence for a Disk Wind?
Chiang, James
We present disk wind model calculations for the broad emission lines seen in the ultraviolet spectra of the X-ray binary Hercules X-1. Recent HST/STIS observations of these lines suggest that they are kinematically linked to the orbital motion of the neutron star and exhibit a redshifted to blueshifted evolution of the line shape during the progre…
Rotational periods of asteroids II
Riccioli, D.; Blanco, C.; Cigna, M.
In the framework of the photoelectric asteroid observational program undertaken at Catania University to collect lightcurves apt to apply the pole computational methods, the V-band lightcurves and the values of the synodic rotational period and of the average B- V colour index of 5 Astrea, 6 Hebe, 12 Victoria, 13 Egeria, 26 Proserpina, 34 Circe, 6…
Propagation of 3-10 MeV electrons in the inner heliosphere: Ulysses observations
Kunow, H.; Heber, B.; Ferrando, P. +3 more
Since the 1970's electrons in the MeV energy range, of Jovian origin, have been extensively studied near the ecliptic from close to the Sun to beyond the Kronian orbit. The Ulysses trajectory provides a unique opportunity to study the propagation of several MeV electrons in a wide range of heliographic latitudes. From the Ulysses launch up to the …
The Solar and Cosmic-Ray Synodic Periodicity (1969 1998)
Rybák, J.; Kudela, K.; Antalová, A.
The synodic recurrence of the Mt. Wilson plage index (MPSI) and the Calgary cosmic ray (CR) intensity is investigated, using the wavelet power spectra in the range of 18 38 days, during the last three solar cycles. The unique temporal coincidence between the quasi synodic MPSI and the CR periods is detected in 1978 1982 (the 21st solar cycle). In …
Solar Origin of a Series of Well-collimated Electron Events
Pick, Monique; Maia, Dalmiro; Hawkins, S. Edward, III +1 more
We investigate the solar origin and propagation of a series of well-collimated energetic electron events on 1997 November 28, measured in situ by the Electron, Proton, and Alpha Monitor (EPAM) experiment on the Advanced Composition Explorer (ACE) spacecraft. EPAM measures electrons in the energy range from 40 to 300 keV over a wide range of look d…
The Cuspy Liner Nucleus of the S0/a Galaxy NGC 2681
Cappellari, Michele; Renzini, Alvio; Greggio, Laura +3 more
The nucleus of the bulge-dominated, multiply barred S0/a galaxy NGC 2681 is studied in detail using the high-resolution Hubble Space Telescope Faint Object Camera (FOC), Near-Infrared Camera and Multiobject Spectrometer (NICMOS) imaging, and the Faint Object Spectrograph (FOS). The ionized gas central velocity dispersion is found to increase by a …
An attempt to detect Vulcanoids with SOHO/LASCO images. I. Scale relativity and quantization of the solar system
Schumacher, G.; Gay, J.
We report an attempt to verify one of the predictions of Scale Relativity theory, namely that a small Vulcanoid should exist at 0.18 AU from the Sun. We have analyzed images taken by the coronograph LASCO aboard the satellite SOHO. Raw images are processed in order to eliminate cosmic ray impacts, stars and to improve the contrast. We have examine…
Dying Pulse Trains in Cygnus XR-1: Evidence for an Event Horizon?
Dolan, Joseph F.
The X-ray-emitting component in the Cyg XR-1/HDE 226868 system is a leading candidate for identification as a stellar-mass-sized black hole. The detection of an event horizon surrounding the point singularity in such a system would constitute a positive identification of a black hole as predicted by general relativity. One signature of such an eve…