Search Publications
Observations of the helium focusing cone with pickup ions
Geiss, J.; Möbius, E.; Noda, H. +12 more
The helium gravitational focusing cone has been observed using pickup He+, first during the solar minimum in 1984-1985 with the AMPTE/IRM spacecraft, and again in more detail from 1998 to 2002 with ACE and in 2000 with Nozomi. Five traversals of the cone allow us to obtain an accurate determination of the ecliptic longitude of the inter…
Deep Hubble Space Telescope ACS Observations of I Zw 18: a Young Galaxy in Formation
Thuan, Trinh X.; Izotov, Yuri I.
We present V and I photometry of the resolved stars in the most metal-deficient blue compact dwarf galaxy known, I Zw 18 (Zsolar/50), using Hubble Space Telescope/ACS images, the deepest ones ever obtained for this galaxy. The resulting I versus V-I color-magnitude diagram (CMD) reaches limiting magnitudes V=I=29 mag. It reveals a young…
Exploring the X-ray sky with the XMM-Newton bright serendipitous survey
Page, M. J.; Barcons, X.; Carrera, F. J. +11 more
We present here ``The XMM-Newton Bright Serendipitous Survey'', composed of two flux-limited samples: the XMM-Newton Bright Source Sample (BSS, hereafter) and the XMM-Newton ``Hard'' Bright Source Sample (HBSS, hereafter) having a flux limit of f_x≃ 7 × 10-14 erg cm-2 s-1 in the 0.5-4.5 keV and 4.5-7.5 keV energy b…
Contribution of the disk emission to the broad emission lines in AGNs: Two-component model
Bon, E.; Popović, L. Č.; Ilić, D. +1 more
We present an investigation of the structure of the emission line region in a sample of 12 single-peaked Active Galactic Nuclei (AGNs). Using the high resolution Hβ and Hα line profiles observed with the Isaac Newton Telescope (La Palma) we study the substructure in the lines (such as shoulders or bumps) which can indicate a disk or disk-like emis…
On the sizes of stellar X-ray coronae
Schmitt, J. H. M. M.; Audard, M.; Güdel, M. +2 more
Spatial information from stellar X-ray coronae cannot be assessed directly, but scaling laws from the solar corona make it possible to estimate sizes of stellar coronae from the physical parameters temperature and density. While coronal plasma temperatures have long been available, we concentrate on the newly available density measurements from li…
Systematic analysis of equatorial noise below the lower hybrid frequency
Santolík, O.; Cornilleau-Wehrlin, N.; Macúšová, E. +3 more
Available from http://www.copernicus.org/site/EGU/annales/22/7/2587.htm?FrameEngine=false;
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 …