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Spectropolarimetric measurements of the mean longitudinal magnetic field of chemically peculiar stars. On the light, spectral and magnetic variability
Leone, F.; Catalano, S.; Catanzaro, G.
We have equipped the spectrograph of the Catania Astrophysical Observatory with a polarimetric module which gives simultaneous circularly right and left polarised radiation spectra. This facility has been used to perform time-resolved spectropolarimetric (Stokes V) measurements of the mean longitudinal (effective) magnetic field for seven chemical…
Near-infrared photometry of isolated spirals with and without an AGN --- II. Photometric properties of the host galaxies
Roth, M.; Durret, F.; González Delgado, R. M. +6 more
We present here the analysis of morphological and photometric properties of a sample of isolated spirals with (18) and without (11) an active nucleus, based on near-infrared imaging in the J and K' bands (Paper I). The aim of that comparative analysis is to find the differential properties that could be directly connected with the phenomenon of nu…
Radiance variations of the quiet Sun at far-ultraviolet wavelengths
Wilhelm, K.; Schühle, U.; Lemaire, P. +2 more
We have measured the radiance of quiet-Sun areas at the centre of the solar disk using the vacuum-ultraviolet telescope-spectrograph SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on the Solar and Heliospheric Observatory (SOHO). The radiances of selected emission lines have been measured from March 1996 to the present. The lines that…
The multiple system LHS 1070: a case study for the onset of dust formation in the atmospheres of very low mass stars
Hauschildt, Peter H.; Richichi, Andrea; Leinert, Christoph +1 more
Multi-wavelength study of the slow ``disparition brusque" of a filament observed with SOHO
Schmieder, B.; Delannée, C.; Yong, Deng Yuan +2 more
A mid-latitude filament was observed before and after its eruption with SOHO (EIT, SUMER, CDS and LASCO) and with ground based observatories (Meudon and Pic du Midi) in the context of a coordinated MEDOC campaign in Orsay. The eruption was followed by a large Coronal Mass Ejection well observed by LASCO. Few hours before its eruption, the filament…
Anatomy of the counterrotating molecular disk in the spiral NGC 3593. 12CO(1-0) interferometer observations and numerical simulations
Hunt, L. K.; Combes, F.; García-Burillo, S. +2 more
This paper presents high-resolution (4arcsec x3arcsec ) interferometer observations of the inner disk of the starburst spiral NGC 3593, made in the (1-0) line of 12CO. NGC 3593 is an early-type system known to possess two counterrotating stellar disks of markedly different scale lengths and masses. The CO emission comes from a highly st…
The structure and momentum of multiple collimated outflows in the protoplanetary nebula Frosty Leo
Sahai, R.; Bujarrabal, V.; Castro-Carrizo, A. +1 more
We have discovered multiple jet-like features in the inner regions of the protoplanetary nebula (PPN) Frosty Leo, in optical images obtained with the Hubble Space Telescope. Frosty Leo is only the second PPN (after CRL2688) and the first oxygen-rich one, to show well-focussed jets close to the equatorial plane. The nebula consists of two bright co…
Global and local bias in the FK5 from the Hipparcos data
Mignard, F.; Frœschlé, M.
Extensive analyses of the FK5 Catalogue with respect to the Hipparcos reference frame have been made in order to determine the overall and local corrections to be applied to any FK5-based secondary frame. The global rotation in position and proper motion is significant, and for the latter, interpreted in term of lack of inertiality of the FK5 fram…
Far infrared extragalactic background radiation --- I. Source counts with ISOPHOT
Juvela, M.; Lemke, D.; Mattila, K.
As a part of the ISOPHOT CIRB (Cosmic Infrared Background Radiation) project we have searched for point-like sources in eight fields mapped at two or three wavelengths between 90 µm and 180 µm. Most of the 55 sources detected are suspected to be extragalactic and cannot be associated with previously known objects. It is probable, also …
An infrared study of the L1551 star formation region
Liseau, R.; White, G. J.; Ceccarelli, C. +14 more
Spectroscopic observations using the Infrared Space Observatory are reported towards the two well known infrared sources and young stellar objects L1551 IRS 5 and L1551 NE, and at a number of locations in the molecular outflow. The ISO spectrum contains several weak gas-phase lines of O I, C II, [Fe II] and [Si II], along with solid state absorpti…