Search Publications
Physical parameters of the high-mass X-ray binary 4U1700-37
Kaper, L.; Crowther, P. A.; Goodwin, S. P. +4 more
We present the results of a detailed non-LTE analysis of the ultraviolet and optical spectrum of the O6.5 Iaf+ star
X-ray spectral imaging and Doppler mapping of Cassiopeia A
Kaastra, J. S.; Vink, J.; Bleeker, J. A. M. +2 more
We present a detailed X-ray spectral analysis of Cas A using a deep exposure from the EPIC-MOS cameras on-board XMM-Newton. Spectral fitting was performed on a 15x15 grid of 20″ x 20″ pixels using a two component non-equilibrium ionisation model (NEI) giving maps of ionisation age, temperature, interstellar column density, abundances for Ne, Mg, S…
XMM-Newton observation of M 87. I. Single-phase temperature structure of intracluster medium
Finoguenov, A.; Böhringer, H.; Matsushita, K. +1 more
We report the results of a detailed analysis of the temperature structure of the X-ray emitting plasma halo of M 87, the cD galaxy of the Virgo Cluster. Using the MEKAL model, the data provide strong indications that the intracluster medium has a single phase structure locally, except the regions associated with the radio structures. The deproject…
Crystalline silicate dust around evolved stars. III. A correlations study of crystalline silicate features
Waters, L. B. F. M.; Tielens, A. G. G. M.; Koike, C. +2 more
We have carried out a quantitative trend analysis of the crystalline silicates observed in the ISO spectra of a sample of 14 stars with different evolutionary backgrounds. We have modeled the spectra using a simple dust radiative transfer model and have correlated the results with other known parameters. We confirm the abundance difference of the …
The mass function of the Arches cluster from Gemini adaptive optics data
Brandner, W.; Grebel, E. K.; Stolte, A. +1 more
We have analysed high resolution adaptive optics (AO) science demonstration data of the young, massive stellar cluster Arches near the Galactic Center, obtained with the Gemini North telescope in combination with the University of Hawai'i AO system Hokupa'a. The AO H and K' photometry is calibrated using HST/NICMOS observations in the equivalent f…
Star formation and dust extinction in nearby star-forming and starburst galaxies
Buat, V.; Boselli, A.; Gavazzi, G. +1 more
We study the star formation rate and dust extinction properties of a sample of nearby star-forming galaxies as derived from Hα and UV ( ~ 2000 Å) observations and we compare them to those of a sample of starburst galaxies. The dust extinction in Hα is estimated from the Balmer decrement and the extinction in UV using the FIR to UV flux ratio or th…
Extragalactic globular clusters in the near-infrared. II. The globular clusters systems of NGC 3115 and NGC 4365
Minniti, D.; Hilker, M.; Kissler-Patig, M. +3 more
We combine near-infrared photometry obtained with the VLT/ISAAC instrument and archival HST/WFPC2 optical images to determine VIK magnitudes and colours of globular clusters in two early-type galaxies, NGC 3115 and NGC 4365. The combination of near-IR and optical photometry provides a way to lift the age-metallicity degeneracy. For NGC 3115, the g…
The FIR/Radio correlation of high redshift galaxies in the region of the HDF-N
Garrett, M. A.
The correlation between the far-infrared (FIR) and radio emission is well established for nearby star forming galaxies. Many applications, in particular the radio-to-submm spectral index redshift indicator, tacitly assume that the relation holds well beyond our local neighbourhood, to systems located at cosmological distances. In order to test thi…
ISO spectroscopy of compact H II regions in the Galaxy. I. The catalogue
Kessler, M. F.; Morisset, C.; Schaerer, D. +9 more
Infrared spectra between 2.3 and 196 µm were taken towards a sample of 45 compact H II regions using the two spectrometers (SWS and LWS) on board ISO. The primary goal is to determine the distribution of element abundances in the Galaxy, although there are also many other uses of this database. The spectra contain a wealth of information on …
An ISO-SWS survey of molecular hydrogen in starburst and Seyfert galaxies
Lutz, D.; Genzel, R.; Rigopoulou, D. +2 more
We present results from a survey of molecular hydrogen emission from a sample of Starburst and Seyfert galaxies carried out with the Infrared Space Observatory (ISO). Pure rotational H2 emission has been detected in a number of extragalactic objects and a variety of environments. A number of transitions from S(7) to S(0) are detected in…