Search Publications
Sinton crater, Mars: Evidence for impact into a plateau icefield and melting to produce valley networks at the Hesperian-Amazonian boundary
Head, James W.; Morgan, Gareth A.
The majority of martian valley networks are found on Noachian-aged terrain and are attributed to be the result of a 'warm and wet' climate that prevailed early in Mars' history. Younger valleys have been identified, though these are largely interpreted to be the result of localized conditions associated with the melting of ice from endogenic heat …
Strong z ~ 0.5 OVI absorption towards PKS 0405-123: implications for ionization and metallicity of the Cosmic Web
Prochaska, J. Xavier; Chen, Hsiao-Wen; Lehner, Nicolas +2 more
We present observations of the intervening OVI absorption-line system at zabs = 0.495096 towards the quasi-stellar object (QSO) PKS 0405-123 (zem = 0.5726) obtained with the Far Ultraviolet Spectroscopic Explorer and Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. In addition to strong OVI, with , an…
A new method of determining distances to dark globules. The distance to B 335
Olofsson, G.; Olofsson, S.
Context: The distance to an isolated dark globule is often unknown and yet crucial for understanding its properties, in particular its mass. A new approach to this problem is discussed
Aims: The purpose of the present paper is to investigate how well the distances of more or less reddened field stars can be determined by using multi-colour ima…
Chandra Observations of the cl1604 Supercluster at z = 0.9: Evidence for an Overdensity of Active Galactic Nuclei
Kocevski, Dale D.; Fassnacht, Christopher D.; Lubin, Lori M. +3 more
We present the results of Chandra observations of the Cl1604 supercluster at z ~ 0.9. The system is the largest structure mapped at redshifts approaching unity, containing at least eight spectroscopically confirmed galaxy clusters and groups. Using two 50 ks ACIS-I pointings we examine both the X-ray point-source population and the diffuse emissio…
Coronal hole boundaries evolution at small scales. I. EIT 195 Å and TRACE 171 Å view
Madjarska, M. S.; Wiegelmann, T.
Aims: We aim to study the small-scale evolution at the boundaries of an equatorial coronal hole connected with a channel of open magnetic flux to the polar region and an “isolated” one in the extreme-ultraviolet spectral range. We determine the spatial and temporal scale of these changes.
Methods: Imager data from TRACE in the Fe ix/x 171 Å pa…
Asteroseismic analysis of the roAp star α Circini: 84d of high-precision photometry from the WIRE satellite
Handler, G.; Kurtz, D. W.; Bruntt, H. +8 more
We present a detailed study of the pulsation of αCircini, the brightest of the rapidly oscillating Ap stars. We have obtained 84d of high-precision photometry from four runs with the star tracker on the WIRE satellite. Simultaneously, we collected ground-based Johnson B observations on 16 nights at the South African Astronomical Observatory. In ad…
On the Origin, 3D Structure and Dynamic Evolution of CMEs Near Solar Minimum
St. Cyr, O. C.; Gopalswamy, N.; Yashiro, S. +4 more
We have conducted a statistical study 27 coronal mass ejections (CMEs) from January 2007 - June 2008, using the stereoscopic views of STEREO SECCHI A and B combined with SOHO LASCO observations. A flux-rope model, in conjunction with 3D triangulations, has been used to reconstruct the 3D structures and determine the actual speeds of CMEs. The orig…
Extended X-Ray Emission in Radio Galaxies: The Peculiar Case of 3C 305
Macchetto, F. D.; Capetti, A.; Gilli, R. +8 more
Extended X-ray structures are common in active galactic nuclei. Here, we present the first case of a compact steep spectrum radio galaxy, 3C 305, in which the X-ray radiation appears to be associated with the optical emission line region, dominated by the [O III]5007. On the basis of a morphological study performed using a comparison between the X…
MESSENGER and Venus Express observations of the solar wind interaction with Venus
Barabash, Stas; Zhang, Tielong; Boardsen, Scott A. +15 more
At 23:08 UTC on 5 June 2007 the MESSENGER spacecraft reached its closest approach altitude of 338 km during its final flyby of Venus en route to its 2011 orbit insertion at Mercury. The availability of the simultaneous Venus Express solar wind and interplanetary magnetic field measurements provides a rare opportunity to examine the influence of up…
Planetary companion candidates around the K giant stars 42 Draconis and HD 139 357
Guenther, E. W.; Pasquini, L.; Hatzes, A. P. +3 more
Context: For the past 3 years we have been monitoring 62 K giant stars using precise stellar radial velocity (RV) measurements with the 2 m Alfred Jensch Telescope of the Thüringer Landessternwarte Tautenburg (TLS).
Aims: To probe the dependence of planet formation on stellar mass by finding planets around intermediate-mass giant stars.
Me…