Search Publications
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
Metallicities of the SPB stars from the IUE ultraviolet spectra
Niemczura, E.
We derived the stellar parameters (angular diameters, effective temperatures, metallicities) and interstellar reddenings for 20 SPB and 34 reference stars observed during the IUE satellite mission. The parameters were derived by means of an algorithmic procedure of fitting theoretical flux distributions to the low-resolution IUE spectra and optica…
Acceleration and Enrichment of 3He in Impulsive Solar Flares by Electron Firehose Waves
Benz, A. O.; Kallenbach, R.; Paesold, G.
A new mechanism for acceleration and enrichment of 3He during impulsive solar flares is presented. Low-frequency electromagnetic plasma waves excited by the electron firehose instability (EFI) can account for the acceleration of ions up to 1 MeV amu-1 energies as a single-stage process. The EFI arises as a direct consequence …
Tracing a Z-track in the M 31 X-ray binary RX J0042.6+4115
Kolb, U.; Osborne, J. P.; Barnard, R.
Four XMM-Newton observations of the core of M 31, spaced at 6 month intervals, show that the brightest point X-ray source, RX J0042.6+4115, has a 0.4-10 keV luminosity of ~ 5x 1038 erg s-1, and exhibits significant variability in intensity and X-ray spectrum over a time scale of ~ 100 s including hard flares; such behaviour i…