Search Publications
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…
Decoupled nuclei and nuclear polar rings in regular spiral galaxies NGC 7217
Sil'chenko, O. K.; Afanasiev, V. L.
The regular isolated Sab galaxy NGC 7217 has been studied with the Multi-Pupil Fiber Spectrograph of the 6m telescope of the Special Astrophysical Observatory RAS (Nizhnij Arkhyz, Russia) in two spectral ranges, the blue one including the strong absorption lines Mg I and Fe I and the red one including the emission lines Hα and [N II]lambda 6583. W…
ISO-SWS calibration and the accurate modelling of cool-star atmospheres. I. Method
Eriksson, K.; Gustafsson, B.; Decin, L. +5 more
A detailed spectroscopic study of the ISO-SWS data of the red giant alpha Tau is presented, which enables not only the accurate determination of the stellar parameters of alpha Tau, but also serves as a critical review of the ISO-SWS calibration. This study is situated in a broader context of an iterative process in which both accurate observation…
The infrared spectrum of the Be star gamma Cassiopeiae
de Graauw, Th.; Waters, L. B. F. M.; Hony, S. +6 more
We present the 2.4-45 µm ISO-SWS spectrum of the Be star gamma Cas (B0.5 IVe). The spectrum is characterised by a thermal continuum which can be well fit by a power-law Snu ~ nu 0.99 over the entire SWS wavelength range. For an isothermal disc of ionized gas with constant opening angle, this correponds to a density gra…
Comparison of far-ultraviolet emission lines formed in coronal holes and the quiet Sun
Solanki, S. K.; Wilhelm, K.; Brković, A. +5 more
We present an analysis of 26 far-ultraviolet emission lines belonging to 19 atoms and ions observed on both sides of the boundary of polar coronal holes as well as other quiet Sun areas along the limb. The observations were made with the SUMER instrument (Solar Ultraviolet Measurements of Emitted Radiation) onboard the Solar and Heliospheric Obser…
ISO-LWS spectroscopy of Centaurus A: extended star formation
Spinoglio, L.; Lord, S. D.; Stacey, G. J. +9 more
We present the first full FIR spectrum of Centaurus A (NGC 5128) from 43 - 196.7 µm. The data was obtained with the ISO Long Wavelength Spectrometer (LWS). We conclude that the FIR emission in a 70 \arcsec beam centred on the nucleus is dominated by star formation rather than AGN activity. The flux in the far-infrared lines is ~ 1% of the to…
VLBI astrometry of the stellar image of U Herculis, amplified by the 1667 MHz OH maser
Baudry, A.; Vlemmings, W.; Beasley, A. J. +2 more
The OH 1667 MHz maser in the circumstellar shell around the Mira variable U Her has been observed with the NRAO Very Long Baseline Array (VLBA) at 6 epochs, spread over 4 years. Using phase referencing techniques the position of the most blue-shifted maser spot was monitored with respect to two extra-galactic radio sources. The absolute radio posi…
The ISO-LWS map of the Serpens cloud core. I. The SEDs of the IR/SMM sources
Olofsson, G.; Liseau, R.; White, G. J. +11 more
Iso-Lws mapping observations of the Serpens molecular cloud core are presented. The spectral range is 50 - 200 µ m and the map size is 8',x 8'. These observations suffer from severe source confusion at Fir wavelengths and we employ a Maximum Likelihood Method for the spectro-spatial deconvolution. The strong and fairly …