Search Publications
Synopsis of the interstellar He parameters from combined neutral gas, pickup ion and UV scattering observations and related consequences
Möbius, E.; Noda, H.; Bzowski, M. +17 more
A coordinated effort to combine all three methods that are used to determine the physical parameters of interstellar gas in the heliosphere has been undertaken. In order to arrive at a consistent parameter set that agrees with the observations of neutral gas, pickup ions and UV backscattering we have combined data sets from coordinated observation…
Double-barred galaxies. I. A catalog of barred galaxies with stellar secondary bars and inner disks
Erwin, Peter
I present a catalog of 67 barred galaxies which contain distinct, elliptical stellar structures inside their bars. Fifty of these are double-barred galaxies: a small-scale, inner or secondary bar is embedded within a large-scale, outer or primary bar. I provide homogenized measurements of the sizes, ellipticities, and orientations of both inner an…
Spatially resolved X-ray spectroscopy of cooling clusters of galaxies
Böhringer, H.; Kaastra, J. S.; Branduardi-Raymont, G. +7 more
We present spatially resolved X-ray spectra taken with the EPIC cameras of XMM-Newton of a sample of 17 cooling clusters and three non-cooling clusters for comparison. The deprojected spectra are analyzed with a multi-temperature model, independent of any a priori assumptions about the physics behind the cooling and heating mechanisms. All cooling…
X-ray emission from a metal depleted accretion shock onto the classical T Tauri star TW Hya
Schmitt, J. H. M. M.; Stelzer, B.
We present the X-ray spectrum of TW Hya observed at high and intermediate spectral resolution with the Reflection Grating Spectrometer (RGS) and the European Photon Imaging Camera (EPIC) onboard the XMM-Newton satellite. TW Hya is the first classical T Tauri star for which simultaneous X-ray data with both high spectral resolution and high sensiti…
Magnetic Doppler imaging of 53 Camelopardalis in all four Stokes parameters
Petit, P.; Piskunov, N.; Wade, G. A. +5 more
We present the first investigation of the structure of the stellar surface magnetic field using line profiles in all four Stokes parameters. We extract the information about the magnetic field geometry and abundance distributions of the chemically peculiar star 53 Cam by modelling time-series of high-resolution spectropolarimetric observations wit…
The dynamical mass of the young cluster W3 in NGC 7252. Heavy-weight globular cluster or ultra compact dwarf galaxy?
Saglia, R. P.; Bastian, N.; Maraston, C. +3 more
We have determined the dynamical mass of the most luminous stellar cluster known to date, i.e. object W3 in the merger remnant galaxy NGC 7252. The dynamical mass is estimated from the velocity dispersion measured with the high-resolution spectrograph UVES on VLT. Our result is the astonishingly high velocity dispersion of σ=45 ± 5 km s-1
X-ray flares reveal mass and angular momentum of the Galactic Center black hole
Grosso, N.; Porquet, D.; Predehl, P. +1 more
We have analysed the light curve of the two brightest X-ray flares from the Galactic Center black hole, one flare observed by XMM-Newton on October 3, 2002 (Porquet et al. \cite{P2003}), and the other flare observed by Chandra on October 26, 2000 (Baganoff et al. \cite{B2001}). The power density spectra show five distinct peaks at periods of ∼100 …
Hard X-ray view of the past activity of Sgr A* in a natural Compton mirror
Gilfanov, M. R.; Sunyaev, R. A.; Sazonov, S. Yu. +6 more
We report the association of the recently discovered hard X-ray source IGR J17475-2822 with the giant molecular cloud Sgr B2 in the Galactic Center region. The broad band (3-200 keV) spectrum of the source constructed from data of different observatories strongly supports the idea that the X-ray emission of Sgr B2 is Compton scattered and reproces…
Some empirical estimates of the H2 formation rate in photon-dominated regions
Boulanger, F.; Walmsley, C. M.; Habart, E. +2 more
We combine recent ISO observations of the vibrational ground state lines of H2 towards Photon-Dominated Regions (PDRs) with observations of vibrationally excited states made with ground-based telescopes in order to constrain the formation rate of H2 on grain surfaces under the physiconditions in the layers responsible for H
A multiwavelength study of solar flare waves. I. Observations and basic properties
Magdalenić, J.; Vršnak, B.; Hanslmeier, A. +2 more
Propagating wave-like disturbances associated with solar flares - commonly observed in the chromosphere as Moreton waves - have been known for several decades. Recently, the phenomenon has come back into focus prompted by the observation of coronal waves with the SOHO/EIT instrument (``EIT waves"). It has been suggested that they represent the ant…