Search Publications
Mid-Infrared line diagnostics of active galaxies. A spectroscopic AGN survey with ISO-SWS
Lutz, D.; Genzel, R.; Sturm, E. +5 more
We present medium resolution (R ~ 1500) ISO-SWS 2.4-45 mu m spectra of a sample of 29 galaxies with active nuclei. This data set is rich in fine structure emission lines tracing the narrow line regions and (circum-)nuclear star formation regions, and it provides a coherent spectroscopic reference for future extragalactic studies in the mid-infrare…
XMM-Newton observation of the Lockman Hole. II. Spectral analysis
Hasinger, G.; Mainieri, V.; Rosati, P. +5 more
We present the results of the X-ray spectral analysis of the first deep X-ray survey with the XMM-Newton observatory during Performance Verification. The X-ray data of the Lockman Hole field and the derived cumulative source counts were reported by Hasinger et al. (2001). We restrict the analysis to the sample of 98 sources with more than 70 net c…
What is the source of the magnetic helicity shed by CMEs? The long-term helicity budget of AR 7978
Thompson, B. J.; Mandrini, C. H.; van Driel-Gesztelyi, L. +5 more
An isolated active region (AR) was observed on the Sun during seven rotations, starting from its birth in July 1996 to its full dispersion in December 1996. We analyse the long-term budget of the AR relative magnetic helicity. Firstly, we calculate the helicity injected by differential rotation at the photospheric level using MDI/SoHO magnetograms…
The Tycho double star catalogue
Makarov, V. V.; Fabricius, C.; Urban, S. E. +3 more
We report the discovery of 13 251 visual double stars, mostly with separations between 0.3 and 1 arcsec, from a dedicated re-reduction of the Tycho data from the star mapper of the ESA Hipparcos satellite. The new doubles are combined with 18 160 WDS systems identified in the Tycho-2two, and 1220 new Tycho-2 doubles, to form the Tycho Double Star …
Stellar and wind properties of LMC WC4 stars. A metallicity dependence for Wolf-Rayet mass-loss rates
Hillier, D. J.; Crowther, P. A.; Fullerton, A. W. +2 more
We use ultraviolet space-based (FUSE, HST) and optical/IR ground-based (2.3 m MSSSO, NTT) spectroscopy to determine the physical parameters of six WC4-type Wolf-Rayet stars in the Large Magellanic Cloud. Stellar parameters are revised significantly relative to Gräfener et al. (\cite{Grafener1998}) based on improved observations and more sophistica…
New distances to galaxies in the Centaurus A group
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +7 more
We present Hubble Space Telescope/WFPC2 images of seventeen dwarf galaxies in the Centaurus A group. Their distances derived from the magnitudes of the tip of the red giant branch are 5.2 Mpc (KK112), 3.2 Mpc (ESO 321-014), 3.5 Mpc (KK179), 3.4 Mpc (NGC 5102), 4.6 Mpc (KK200), 3.7 Mpc (ESO 324-024), 4.7 Mpc (KK208), 4.6 Mpc (ESO 444-084), 4.4 Mpc …
The new emerging model for the structure of cooling cores in clusters of galaxies
Böhringer, H.; Churazov, E.; Chen, Y. +2 more
New X-ray observations with XMM-Newton show a lack of spectral evidence for large amounts of cooling and condensing gas in the centers of galaxy clusters believed to harbour strong cooling flows. This paper re-explores the cooling flow scenario in the light of the new observations. We explore the diagnostics of the temperature structure of cooling…
The mass profile of A1413 observed with XMM-Newton: Implications for the M-T relation
Arnaud, M.; Pratt, G. W.
We present an XMM-Newton et al. observation of A1413, a hot (kT = 6.5 kev ) galaxy cluster at z=0.143. We construct gas and temperature profiles over the radial range up to ~ 1700 kpc. This radius corresponds to a density contrast delta ~ 500 with respect to the critical density at the redshift of the cluster, or equivalently ~ 0.7 r200…
Crystalline silicate dust around evolved stars. II. The crystalline silicate complexes
Waters, L. B. F. M.; Tielens, A. G. G. M.; Molster, F. J.
This is the second paper in a series of three in which we present an exhaustive inventory of the solid state emission bands observed in a sample of 17 oxygen-rich dust shells surrounding evolved stars. The data were taken with the Short and Long Wavelength Spectrographs on board of the Infrared Space Observatory (ISO) and cover the 2 to 200 mu m w…
The very local Hubble flow
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +8 more
We present Hubble Space Telescope/WFPC2 images of eighteen galaxies situated in the vicinity of the Local Group (LG) as part of an ongoing snapshot survey of nearby galaxies. Their distances derived from the magnitude of the tip of the red giant branch are 1.92±0.10 Mpc (ESO 294-010), 3.06±0.37 (NGC 404), 3.15±0.32 (UGCA 105), 1.36±0.07 (Sex B), 1…