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X-Ray Spectroscopy of η Carinae with XMM-Newton
Ramsay, Gavin; Leutenegger, Maurice A.; Kahn, Steven M.
We present XMM-Newton observations of the luminous star η Carinae, including a high-resolution soft X-ray spectrum of the surrounding nebula obtained with the Reflection Grating Spectrometer (RGS). The European Photon Imaging Camera (EPIC) image of the field around η Car shows many early-type stars and diffuse emission from hot, shocked gas. The E…
Does the Sun Shrink with Increasing Magnetic Activity?
Antia, H. M.
It has been demonstrated that frequencies of f-modes can be used to estimate the solar radius to a good accuracy. These frequencies have been used to study temporal variations in the solar radius with conflicting results. The variation in f-mode frequencies is more complicated than what is assumed in these studies. If a careful analysis is perform…
An Icy, Bipolar Proto-Planetary Nebula with Knotty Jets: IRAS 22036+5306
Sahai, R.; Sánchez Contreras, C.; Zijlstra, A. +1 more
Using the Hubble Space Telescope's Wide Field Planetary Camera 2, we have discovered that the proto-planetary nebula (PPN) IRAS 22036+5306 (I22036) is an extended (5.7"×1.3") bipolar nebula. A dark, (partial) ringlike band defines the nebular waist region and probably results from a tilted, geometrically thick disk that obscures the central star. …
On the Progenitor of Supernova 2001du in NGC 1365
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Li, Weidong
Hubble Space Telescope (HST) WFPC2 archival images obtained years prior to the explosion of the Type II-plateau supernova (SN) 2001du in NGC 1365 previously have been analyzed to isolate the progenitor star. The SN site was located using precise astrometry applied to the HST images, with significant uncertainty, leaving three possible progenitor c…
INTEGRAL timing and localization performance
Walter, R.; Schmidt, M.; Kuiper, L. +10 more
In this letter we report on the accuracy of the attitude, misalignment, orbit and time correlation which are used to perform scientific analyses of the INTEGRAL data. The boresight attitude during science pointings has an accuracy of 3 arcsec. At the center of the field, the misalignments have been calibrated leading to a location accuracy of 4 to…
Line emission from circumstellar disks around A stars
Kamp, I.; van Dishoeck, E. F.; Stark, R. +1 more
The nature of the tenuous disks around A stars has raised considerable controversy in the literature during the past decade. The debate whether or not the disk around beta Pictoris contains gaseous molecular hydrogen is only the most recent example. Since CO is in general a poor tracer for the gas content of these low mass disks, we discuss here d…
Detection of X-Ray Emission from the Eastern Radio Lobe of Pictor A
Guainazzi, Matteo; Morganti, Raffaella; Tavecchio, Fabrizio +5 more
The XMM-Newton satellite has revealed extended X-ray emission from the eastern radio lobe of the Fanaroff-Riley II radio galaxy Pictor A. The X-ray spectrum, accumulated on a region covering about half the entire radio lobe, is well described by both a thermal (kT=5+9-2 keV) model and a power law with an energy index αX<…
The complete submillimetre spectrum of NGC 891
Bernard, J. -P.; Dupac, X.; Giard, M. +8 more
Submillimetre maps of NGC 891 have been obtained with the Programme National d'Observations Submillimétriques (PRONAOS) balloon-borne telescope and with the Infrared Space Observatory Photopolarimeter (ISOPHOT) on board the ISO satellite. In this article, we also gather data from the Infrared Astronomical Satellite (IRAS) and the Submillimetre Com…
Charge-sign dependent modulation in the heliosphere over a 22-year cycle
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +1 more
A time-dependent model based on a numerical solution of Parker's transport equation is used to model the modulation of cosmic ray protons, electrons and helium for full 11-year and 22-year modulation cycles using a compound approach. This approach incorporates the concept of propagating diffusion barriers based on global increases in the heliosphe…
A submillimetre selected quasar in the field of Abell 478
Jaffe, W.; Knudsen, K. K.; van der Werf, P. P.
We present the discovery of a dusty quasar, SMM J04135+10277, located behind the galaxy cluster