Search Publications
Automatic detection of arcs and arclets formed by gravitational lensing
Schindler, S.; Lenzen, F.; Scherzer, O.
We present an algorithm developed particularly to detect gravitationally lensed arcs in clusters of galaxies. This algorithm is suited for automated surveys as well as individual arc detections. New methods are used for image smoothing and source detection. The smoothing is performed by so-called anisotropic diffusion, which maintains the shape of…
Dust and super star clusters in NGC 5253
Sauvage, M.; Vanzi, L.
We present new observations of the famous starburst galaxy NGC 5253 which owes its celebrity to possibly being the youngest and closest starburst galaxy known. Our observations in the infrared and millimeter contribute to shed light on the properties of this interesting object. We have used our new data along with data from the literature to study…
Detection of a companion to the pulsating sdB Feige 48
Heber, U.; Benjamin, R. A.; O'Toole, S. J.
We present the discovery of a binary companion to the pulsating sdB Feige 48. Using HST/STIS and archival FUSE spectra, we measure a period of 0.376±0.003 d and a velocity semi-amplitude of 28.0±0.2 km s-1. This implies that the companion star must either be of very low mass, or the orbit is at low inclination. Combining 2MASS fluxes, t…
Unveiling the nature of the highly obscured active galactic nucleus in NGC 5643 with XMM-Newton
Guainazzi, M.; Iwasawa, K.; Fabian, A. C. +2 more
We present results from an XMM-Newton observation of the nearby Seyfert 2 galaxy NGC 5643. The nucleus exhibits a very flat X-ray continuum above 2 keV, together with a prominent Kα fluorescent iron line. This indicates heavy obscuration. We measure an absorbing column density NH in the range 6-10 × 1023 cm-2, eith…
Simultaneous Production of Disk and Lobes: A Single-Wind MHD Model for the η Carinae Nebula
Balick, Bruce; Matt, Sean
The luminous blue variable η Carinae is surrounded by a complex and highly structured nebula of ejected material. The best-studied and axisymmetric components of this outflow consist of bipolar lobes (the ``homunculus'') and an equatorial ``skirt.'' Recent proper-motion measurements suggest that the skirt was ejected at the same time as the lobes,…
Abundance of Substructure in Clusters of Galaxies
Springel, Volker; Natarajan, Priyamvada
It is widely recognized that cold dark matter (CDM) models predict abundant dark matter substructure in halos of all sizes. Galaxy-galaxy lensing provides a unique opportunity to directly measure the presence and the mass of such substructures in clusters of galaxies. Here we present the mass function of substructures obtained from lensing in mass…
Characteristics of magnetospherically reflected chorus waves observed by CLUSTER
Santolík, O.; Gurnett, D.; Parrot, M. +2 more
Available from http://www.copernicus.org/site/EGU/annales/22/7/2597.htm?FrameEngine=false;
Variations in the Spin Period of the Radio-quiet Pulsar 1E 1207.4-5209
Pavlov, George G.; Zavlin, Vyacheslav E.; Sanwal, Divas
The X-ray source 1E 1207.4-5209 is a compact central object in the G296.5+10.0 supernova remnant. Its spin period of 424 ms, discovered with Chandra, suggests that it is a neutron star. The X-ray spectrum of this radio-quiet pulsar shows at least two absorption lines, the first spectral features discovered in radiation from an isolated neutron sta…
Simultaneous observations of field-aligned beams and gyrating ions in the terrestrial foreshock
Dandouras, I.; Klecker, B.; Lucek, E. A. +14 more
We examine an energetic (2-30 keV) upstream ion event presenting a clear double-peak spectrum observed ∼1 RE upstream from the bow shock. The lower-energy (E ∼ 3.5 keV) peak is associated with an ion beam propagating along the magnetic field direction, while the higher-energy (E ∼ 13 keV) peak is associated with gyrating ions having pit…
XMM-Newton Observation of the Merging Galaxy Cluster A1644
Sarazin, Craig L.; Reiprich, Thomas H.; Tittley, Eric +1 more
We present an XMM-Newton imaging spectroscopy analysis of the galaxy cluster A1644. A1644 is a complex merging system consisting of a main cluster and a subcluster. A trail of cool, metal-rich gas has been discovered close to the subcluster. The combination of results from X-ray, optical, and radio data and a comparison to a hydrodynamic simulatio…