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GMASS ultradeep spectroscopy of galaxies at z ~ 2 . I. The stellar metallicity
Berta, S.; Cimatti, A.; Daddi, E. +12 more
Context: Galaxy metallicities have been measured to redshift z∼2 by gas-phase oxygen abundances of the interstellar medium using the R{23} and N2 methods. Galaxy stellar metallicities provide crucial data for chemical evolution models but have not been assessed reliably much outside the local Universe.
Aims: We determine the iron-abundance, st…
A Test of Three Optical Flow Techniques—LCT, DAVE, and NAVE
Chae, Jongchul; Sakurai, Takashi
A time sequence of high-quality images currently produced by high-resolution observations either from the ground or in space may be utilized to determine the transverse flow field on the plane of the sky with the help of optical flow techniques. We have examined the performance of three different methods—a well-known technique called local correla…
Observational Test of Coronal Magnetic Field Models. I. Comparison with Potential Field Model
Liu, Yu; Lin, Haosheng
Recent advances have made it possible to obtain two-dimensional line-of-sight magnetic field maps of the solar corona from spectropolarimetric observations of the Fe XIII 1075 nm forbidden coronal emission line. Together with the linear polarization measurements that map the azimuthal direction of the coronal magnetic field projected in the plane …
Is the Gini Coefficient a Stable Measure of Galaxy Structure?
Lisker, Thorsten
The Gini coefficient, a nonparametric measure of galaxy morphology, has recently taken up an important role in the automated identification of galaxy mergers. I present a critical assessment of its stability, based on a comparison of HST ACS imaging data from the GOODS and UDF surveys. Below a certain signal-to-noise level, the Gini coefficient de…
Impact effects from small size meteoroids and space debris
Drolshagen, Gerhard
When the impact risk from meteoroids and orbital debris is assessed the main concern is usually structural damage. With their high impact velocities of typically 10 20 km/s millimeter or centimeter sized objects can puncture pressure vessels and other walls or lead to destruction of complete subsystems or even whole spacecraft. Fortunately chances…
Conservation of open solar magnetic flux and the floor in the heliospheric magnetic field
St. Cyr, O. C.; Owens, M. J.; Crooker, N. U. +5 more
The near-Earth heliospheric magnetic field intensity, |B|, exhibits a strong solar cycle variation, but returns to the same ``floor'' value each solar minimum. The current minimum, however, has seen |B| drop below previous minima, bringing in to question the existence of a floor, or at the very least requiring a re-assessment of its value. In this…
Kinematic properties of solar coronal mass ejections: Correction for projection effects in spacecraft coronagraph measurements
Howard, T. A.; Nandy, D.; Koepke, A. C.
One of the main sources of uncertainty in quantifying the kinematic properties of coronal mass ejections (CMEs) using coronagraphs is the fact that coronagraph images are projected into the sky plane, resulting in measurements which can differ significantly from their actual values. By identifying solar surface source regions of CMEs using X-ray a…
Two-dimensional kinematics of SLACS lenses - I. Phase-space analysis of the early-type galaxy SDSSJ2321-097 at z ~ 0.1
Treu, Tommaso; Czoske, Oliver; Koopmans, Léon V. E. +2 more
We present the first results of a combined VLT VIMOS integral-field unit and Hubble Space Telescope (HST)/ACS study of the early-type lens galaxy SDSSJ2321-097 at z = 0.0819, extending kinematic studies to a look-back time of 1Gyr. This system, discovered in the Sloan Lens ACS Survey, has been observed as part of a VLT Large Programme with the goa…
XMM-Newton observations of the Small Magellanic Cloud: Be/X-ray binary pulsars active between October 2006 and June 2007
Pietsch, W.; Haberl, F.; Eger, P.
Aims: We analysed eight XMM-Newton observations toward the Small Magellanic Cloud (SMC), performed between October 2006 and June 2007, to investigate high mass X-ray binary systems.
Methods: We produced images from the European Photon Imaging Cameras (EPIC) and extracted X-ray spectra and light curves in different energy bands from sources tha…
X-Ray and Near-IR Variability of the Anomalous X-Ray Pulsar 1E 1048.1-5937: From Quiescence Back to Activity
Kaspi, Victoria M.; Bassa, Cees; Woods, Peter M. +3 more
We report on new and archival X-ray and near-IR observations of the anomalous X-ray pulsar 1E 1048.1-5937 performed between 2001 and 2007 with the Rossi X-Ray Telescope Explorer (RXTE), the Chandra X-Ray Observatory, the Swift Gamma-Ray Burst Explorer, the Hubble Space Telescope (HST), and the Very Large Telescope. Monitoring with RXTE revealed th…