Search Publications
The ISO spectra of Uranus and Neptune between 2.5 and 4.2 mu m: constraints on albedos and H_3+
Lellouch, E.; Feuchtgruber, H.; Atreya, S. K. +3 more
Spectra of Uranus and Neptune were recorded in May 1997, between 2.5 and 4.2 mu m, using the ISOPHOT-S instrument. The two planets were detected at 2.75 mu m, with geometric albedos of 0.0015 and 0.0052 for Uranus and Neptune respectively. In the case of Uranus, the shape of the CH_4 absorption is consistent with a reflection over the 3 bar-level …
EUV brightness variations in the quiet Sun
Solanki, S. K.; Harrison, R. A.; Fludra, A. +5 more
The Coronal Diagnostic Spectrometer (CDS) onboard the SOHO satellite has been used to obtain movies of quiet Sun regions at disc centre. These movies were used to study brightness variations of solar features at three different temperatures sampled simultaneously in the chromospheric He I 584.3 Ä (2 * 104 K), the transition region O V 6…
IRAS galaxies in the Perseus cluster
Meusinger, H.; Brunzendorf, J.; Krieg, R.
We cross-correlate the optical catalogue of galaxies in the field of the Perseus cluster (Abell 426) with IRAS PSC sources. The optical catalogue comprises data on 660 galaxies brighter than B25 ~ 19.5 (Brunzendorf & Meusinger 1999). A sample of 19 IRAS galaxies is found. According to their redshifts, 17 galaxies are likely members …
Far infrared observations of the southern Galactic star forming complex around IRAS 09002-4732
Ghosh, S. K.; Mookerjea, B.; Tandon, S. N. +2 more
The Galactic star forming region in the southern sky, associated with IRAS 09002-4732 has been mapped simultaneously in two far infrared bands (lambda eff = 148 & 209 mu m), with ~ 1 arcmin angular resolution. Fifteen sources, including IRAS 08583-4719, 08589-4714, 09002-4732 and 09014-4736 have been detected, some of which are well…
Direct measurement of the supernova rate in starburst galaxies
Bregman, J. D.; Temi, P.; Rank, D.
Supernovae play a key role in the dynamics, structure, and chemical evolution of galaxies. The massive stars that end their lives as supernovae live for short enough times that many are still associated with dusty star formation regions when they explode, making them difficult to observe at visible wavelengths. In active star forming regions (gala…
Internal velocity dispersion in the Hyades as a test for Tycho-2 proper motions
Makarov, V. V.; Odenkirchen, M.; Urban, S.
The Hyades stars have highly coherent motions in space which reflect in the convergence of their astrometric proper motions in or about a common convergent point. The internal dispersion of the Hyades velocities is as low as about 0.3 km s-1. This is comparable with the expected uncertainty of the Tycho-2 proper motion at the distance o…
ISO far-infrared observations of rich galaxy clusters. II. Sérsic 159-03
Nørgaard-Nielsen, H. U.; Pedersen, K.; Hansen, L. +3 more
In a series of papers we investigate far-infrared emission from rich galaxy clusters. Maps have been obtained by ISO at 60 µm, 100 µm, 135 µm, and 200 µm using the PHT-C camera. Ground based imaging and spectroscopy were also acquired. Here we present the results for the cooling flow cluster Sérsic 159-03. An infrared sourc…
Solar transition region line broadening: Limb to limb measurements
Doyle, J. G.; Teriaca, L.; Banerjee, D.
Full disk images from SUMER/SoHO taken in He I, C IV and Ne VIII are used to investigate whether there exists a center-to-limb variation in the line width. Both C IV and He I show such a variation but the higher temperature Ne VIII line is relatively constant. For C IV, this corresponds to ~ 3 km s-1 difference while He I is significant…
ISO observations of the BL Lacertae object PKS 2155-304
Maraschi, L.; Tagliaferri, G.; Ghisellini, G. +5 more
The BL Lacertae object PKS 2155-304 was observed by the Infrared Space Observatory in May and June 1996, during a multiwavelength campaign. These are the first observations in the mid- and far-infrared bands since IRAS. In the observing period, the source showed no detectable time variability at 4.0, 14.3, 60 and 90 mu m. The spectrum from 2.8 to …
First results of UVES at VLT: revisiting RR Tel
Bonifacio, P.; Selvelli, P. L.
We present here the first results of UVES observations of RR Tel. The exceptional performances of the instrument have allowed the detection of new spectral features and have led to an improvement in the identifications of several emission lines. A direct comparison with the IUE observations in the range 3045-3300 Åhas revealed the appearance of ma…