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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 …
The cold dust concentrations in the colliding galaxies NGC 4038/39
Klaas, U.; Haas, M.; Xu, C. +2 more
SCUBA 450 and 850 mu m maps of the Antennae Galaxy resolve the nuclei of NGC 4038/39 and two prominent regions in the overlap area of the galaxy disks. They coincide excellently with bright emission peaks seen on 15 mu m, 6 cm and CO maps. ISOPHOT 60 and 100 mu m maps reveal that the overlap area and the NGC 4038 nucleus are also responsible for t…
The effective temperature scale of giant stars (F0-K5). III. Stellar radii and the calibration of convection
Salaris, M.; Arribas, S.; Asensio Ramos, A. +2 more
We present an analysis of radii of giant stars with 6200 K>= T_eff >= 3800 K based on angular diameters obtained by means of the IRFM and distances computed from Hipparcos parallaxes. In order to asses the reliability of IRFM diameters we have considered a selected sample of stars whose diameters have been directly measured by interferometri…
ISO-LWS observations of rotational CO lines from C-rich objects: AFGL 2688, AFGL 618 and NGC 7027
Justtanont, K.; Barlow, M. J.; Tielens, A. G. G. M. +6 more
We present ISO-LWS full scan observations of CO rotational emission lines (J=14-13 up to J=37- 36) from two C-rich post-AGB objects, AFGL 2688; AFGL 618, and one C-rich PN, NGC 7027. The presence of high rotational lines cannot be explained by a spherical, constant velocity wind during the previous AGB phase, but indicates a layer of warm, dense g…