Search Publications
SWS spectroscopy of the colliding galaxies NGC4038/39.
Lutz, D.; Genzel, R.; Sturm, E. +8 more
We present mid-infrared spectroscopy of the prototypical interacting galaxies NGC 4038/39 (the `Antennae') obtained with the ISO Short Wavelength Spectrometer (SWS). Our observations focus on the interaction zone where the two galaxies overlap, providing new constraints on the properties of the young and vigorous extranuclear starburst triggered b…
Secular variations in the Z source CygnusX-2.
van der Klis, M.; Kuulkers, E.; Vaughan, B. A.
We analyzed the X-ray spectral variations of the low-mass X-ray binary CygX-2 on time scales longer than one day using EXOSAT data. We describe these variations in terms of the shifts and shape changes of the "Z" pattern in X-ray colour-colour and hardness-intensity diagrams. CygX-2 varies between three intensity "levels": "high", "medium" and "lo…
The ISO-SWS spectrum of NML Cyg.
Waters, L. B. F. M.; Beintema, D. A.; Izumiura, H. +9 more
The high resolution spectrum of NML Cyg observed with the ISO-SWS in its slow-speed grating mode (2.4-45µm) shows a wealth of features never seen before in previous observations. These include ro-vibrational lines of H_2_O at 2.7 and 6.2µm, of OH between 3 and 3.5µm and a deep absorption band of CO_2_ at 4.26µm. We also rep…
The Sombrero galaxy. II. Colours, kinematics and line strengths of the central region.
Emsellem, E.; Bacon, R.; Monnet, G. +1 more
We present photometric (pre-COSTAR HST and ground-based) and new two-dimensional TIGER spectrographic data of the central region of the Sombrero galaxy (NGC 4594, M 104). This gives B-V and V-R_C_ images, as well as 2D line strengths and kinematical maps (LOSVDs). Analysis of these data lets us draw a clearer picture of the morphology of the Sombr…
The mass distribution of CL0939+4713 obtained from a `weak' lensing analysis of a WFPC2 image.
Kneib, J. -P.; Schneider, P.; Seitz, S. +1 more
The image distortions of high-redshift galaxies caused by gravitational light deflection of foreground clusters of galaxies can be used to reconstruct the two-dimensional surface mass density of these clusters. We apply an unbiased parameter-free reconstruction technique to the cluster CL0939+4713 (Abell 851), observed with the WFPC2 on board of t…
The ISO LWS grating spectrum of NGC 7027.
Walker, H. J.; Omont, A.; Ade, P. A. R. +39 more
We present a high signal-to-noise ISO Long Wavelength Spectrometer (LWS) grating spectrum of the planetary nebula NGC 7027 from 43-194µm. In total 40 emission lines have been detected, with 30 identified. From the ionized region, we observe fine-structure lines from [N II], [N III] and [O III]. The [O I] and [C II] fine-structure lines from …
Detection of hot, abundant water toward AFGL 2591.
Heras, A. M.; Beintema, D. A.; de Graauw, T. +6 more
We present the first detection of absorption lines within the bending vibration of water in the interstellar medium using the ISO-SWS. More than 30 lines between 5.5 and 6.6µm are detected toward the bright infrared source GL 2591, which arise most likely in the dense molecular cloud core surrounding the young stellar object. Comparison with…
The wavelength calibration and resolution of the SWS.
Lutz, D.; Heras, A. M.; Beintema, D. A. +21 more
The laboratory wavelength calibration of the SWS has been succesfully transferred to the in orbit situation. The achieved accuracies for the grating sections are λ/δλ~10000. Any remaining errors in the wavelength scale are dominated by uncertainties of the relative position of the target in the 14"-20" wide slits. The grating spectral profile is v…
ISOCAM observations of low-luminosity young stellar objects in the Chamaeleon dark clouds.
Prusti, T.; Perault, M.; Olofsson, G. +19 more
We report the first results from an ISOCAM survey for low-luminosity, young stellar objects (YSOs) in nearby star formation regions. The present Letter concerns three regions within the Chamaeleon dark clouds, with a total area coverage of ~0.8 square degrees, representing 35% of the presently approved survey programme. The survey is conducted in …
The behaviour of the excess CA II H and K and Hɛ emissions in chromospherically active binaries.
Montes, D.; Fernandez-Figueroa, M. J.; de Castro, E. +1 more
In this work we analyze the behaviour of the excess Ca II H and K and Hɛ emissions in a sample of 73 chromospherically active binary systems (RS CVn and BY Dra classes), of different activity levels and luminosity classes. This sample includes the 53 stars analyzed by Fernandez-Figueroa et al. (1994) and the observations of 28 systems described by…