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Revealing a Cool Accretion Disk in the Ultraluminous X-Ray Source M81 X-9 (Holmberg IX X-1): Evidence for an Intermediate-Mass Black Hole
Fabian, A. C.; Miller, J. M.; Miller, M. C.
We report the results of an analysis of two XMM-Newton EPIC-pn spectra of the bright ultraluminous X-ray source M81 X-9 (Holmberg IX X-1) obtained in snapshot observations. Soft thermal emission is clearly revealed in spectra dominated by hard power-law components. Depending on the model used, M81 X-9 was observed at a luminosity of LX=…
Physical Properties and Baryonic Content of Low-Redshift Intergalactic Lyα and O VI Absorption Line Systems: The PG 1116+215 Sight Line
Richter, Philipp; Tripp, Todd M.; Sembach, Kenneth R. +1 more
We present Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer observations of the intergalactic absorption toward QSO PG 1116+215 in the 900-3000 Å spectral region. We detect 25 Lyα absorbers along the sight line at rest-frame equivalent widths Wr>30 mÅ, yielding (dN/dz)Lyα=166+/-20 over an unblocked redshif…
Bright OB stars in the Galaxy. I. Mass-loss and wind-momentum rates of O-type stars: A pure H\alpha analysis accounting for line-blanketing
Puls, J.; Markov, H.; Markova, N. +1 more
We study mass-loss and wind momentum rates of 29 Galactic O-type stars with luminosity classes I, III and V by means of a pure H\alpha profile analysis and investigate to what extent the results compare to those originating from a state-of-the-art, complete spectral analysis. Our investigation relies on the approximate method developed by \citet{P…
The Abundance of Low-Luminosity Lyα Emitters at High Redshift
Richard, Johan; Ellis, Richard S.; Kneib, Jean-Paul +2 more
We derive the luminosity function of high-redshift Lyα-emitting sources from a deep, blind, spectroscopic survey that utilized strong-lensing magnification by intermediate-redshift clusters of galaxies. We observed carefully selected regions near nine clusters, consistent with magnification factors generally greater than 10 for the redshift range …
A large population of `Lyman-break' galaxies in a protocluster at redshift z ~ 4.1
White, Richard L.; Franx, Marijn; Illingworth, Garth D. +35 more
The most massive galaxies and the richest clusters are believed to have emerged from regions with the largest enhancements of mass density relative to the surrounding space. Distant radio galaxies may pinpoint the locations of the ancestors of rich clusters, because they are massive systems associated with `overdensities' of galaxies that are brig…
Elemental abundances in the intracluster medium as observed with XMM-Newton
Kaastra, J. S.; Tamura, T.; Bleeker, J. A. M. +2 more
XMM-Newton observations of 19 galaxy clusters are used to measure the elemental abundances and their spatial distributions in the intracluster medium. The sample mainly consists of X-ray bright and relaxed clusters with a cD galaxy. Along with detailed Si, S and Fe radial abundance distributions within 300-700 kpc in radius, the O abundances are a…
Isolated electrostatic structures observed throughout the Cluster orbit: relationship to magnetic field strength
Balogh, A.; Santolík, O.; Chen, L. +4 more
Available from http://www.copernicus.org/site/EGU/annales/22/7/2515.htm?FrameEngine=false;
The Contribution of Primordial Binaries to the Blue Straggler Population in 47 Tucanae
Ferraro, Francesco R.; Sills, Alison; Beccari, Giacomo +5 more
Recent observations of the blue straggler population in 47 Tucanae give the first detailed characterization of their spatial distribution in the cluster over its entire volume. Relative to the light distribution, blue stragglers appear to be overabundant in the core and at large radii. The observed surface density profile shows a central peak, a z…
Lithium abundances of the local thin disc stars
Lambert, David L.; Reddy, Bacham E.
Lithium abundances are presented for a sample of 181 nearby F and G dwarfs with accurate Hipparcos parallaxes. The stars are on circular orbits about the Galactic centre and, hence, are identified as belonging to the thin disc. This sample is combined with two published surveys to provide a catalogue of lithium abundances, metallicities ([Fe/H]), …
Dust and Diffuse Interstellar Bands in the za = 0.524 Absorption System toward AO 0235+164
Cohen, Ross D.; Burbidge, E. M.; Lyons, R. W. +3 more
We present new Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) NUV-MAMA and STIS CCD observations of the BL Lac object AO 0235+164 and the intervening damped Lyα (DLA) line at za=0.524. The line profile gives N(HI)=(5+/-1)×1021 cm-2 and, combined with the H I 21 cm absorption data, leads to…