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Multi-spacecraft observations of diffuse ions upstream of Earth's bow shock
Klecker, B.; Kistler, L. M.; Lucek, E. A. +6 more
We report on simultaneous measurements of energetic ions upstream of Earth's quasi-parallel bow shock by Cluster during a 10 hour time period when the inter-spacecraft separation distance was between ~1 and ~1.5 Re. Using a bow shock model we determined for each 32 s averaged data set the distance of the Cluster 1 and Cluster 3 spacecra…
The kinetic shell model of coronal heating and acceleration by ion cyclotron waves: 3. The proton halo and dispersive waves
Isenberg, Philip A.
The kinetic shell model seeks to test the collisionless kinetic response of coronal hole protons to the quasi-linear resonant cyclotron dissipation of outwardly directed, parallel propagating ion cyclotron waves, which is often invoked as the mechanism responsible for generating the fast solar wind. In this model, we make the approximation that th…
Resolving the Large-Scale Spectral Variability of the Luminous Seyfert 1 Galaxy 1H 0419-577: Evidence for a New Emission Component and Absorption by Cold Dense Matter
O'Brien, P. T.; Reeves, J. N.; Page, K. L. +1 more
An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in 2002 September, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below ~1 keV. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was ``X-ray bright'' indicated that the dominant spectral…
On the Formation of the Resonance Lines of Helium in the Sun
Judge, Philip G.; Pietarila, Anna
To investigate the cause of anomalously bright resonance lines of helium in the Sun, we have studied the magnitude of the enhancements and some proposals made to explain them. Calculations in new semiempirical solar models indicate that the resonance lines of helium are enhanced by factors of 2-5 for He I and between 2 and 9 for He II, depending o…
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…