Search Publications
AXPs and X-ray-dim isolated neutron stars: recent XMM-Newton and Chandra results
Haberl, F.
To date more than half a dozen X-ray-dim isolated neutron stars are known. Their X-ray spectra are characterized by soft blackbody-like emission ( kT∼50-120 eV) without indication for harder, non-thermal components. These stars apparently show no radio emission and no association with supernova remnants. Four of them exhibit pulsations in their X-…
Kinetic parameters of interstellar neutral helium: updated results from the ULYSSES/GAS-instrument
Rosenbauer, H.; Witte, M.; Banaszkiewicz, M. +1 more
The GAS-instrument onboard the space probe ULYSSES (ULS) is designed to measure the local angular distribution of the flow of interstellar neutral He-atoms within ≈3 AU distance from the sun; it allows to infer the kinetic parameters (velocity vector, temperature and density) of these particles outside the heliosphere ("at infinity"). Around the s…
Composition of the local interstellar medium as diagnosed with pickup ions
Gloeckler, George; Geiss, Johannes
Pickup ions provide us with a powerful tool to probe remote regions in and beyond the heliosphere and determine the composition of the neutral gas in these regions. Interstellar pickup ions, observed inside the heliosphere at 3-5 AU from the Sun, are created by charge exchange and photoionization of the local interstellar gas that penetrates deep …
Variability of solar eruptions during cycle 23
Howard, R. A.; Gopalswamy, N.; Yashiro, S. +1 more
We report on the solar cycle variation of the rate of coronal mass ejections (CMEs), their mean and median speeds, and the rate of type II radio bursts. We found that both CME rate and speed (mean and median) increased from solar minimum to maximum by factors of 10 and 2, respectively. The CME rate during solar maximum is nearly twice the rates qu…
The origin of the slow solar wind in coronal streamers
Ofman, L.
The highly variable slow solar wind has been associated with low-latitude regions of the heliosphere most clearly by the Ulysses spacecraft. Although, it is evident today that the slow solar wind originates in coronal helmet streamers, the mechanism of the slow solar wind acceleration, and the origin of the variability are still being debated. The…
The heliospheric hydrogen wall and astrospheres
Linsky, J. L.; Zank, G. P.; Wood, B. E. +2 more
Charge exchange processes in the outer heliosphere produce a population of hot hydrogen gas within the heliosphere, creating a "hydrogen wall" between the heliopause and bow shock. The heliospheric hydrogen wall scatters Lyα photons passing through it, producing a detectable absorption signature in observations of H I Lyα emission from nearby star…
Shocks and particle acceleration in supernova remnants: observational features
Vink, Jacco
The last 10 years a number of observational advances have substantially increased our knowledge of shock phenomena in supernova remnants. This progress has mainly been made possible by the recent improvements in X-ray and γ-ray instrumentation. It has become clear that some shell-type supernova remnants, e.g., SN 1006, have X-ray emission dominate…
XMM-Newton observations of the field of γ-ray burst 980425
Piro, L.; Pian, E.; Palazzi, E. +12 more
The error box of GRB980425 has been observed by XMM- Newton in March 2002, with the aim of measuring the late epoch X-ray emission of the supernova 1998bw and of clarifying its supposed association with the GRB itself. We present here the preliminary results obtained with the EPIC PN camera. Our observations confirm the association between SN 1998…
Low-latitude coronal holes during solar maximum
Cranmer, S. R.; Kohl, J. L.; Miralles, M. P.
The Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO has been used to observe large low-latitude coronal holes during solar maximum that produced fast solar wind streams. UVCS observations show that large low-latitude coronal holes at solar maximum, coronal holes of at least 10° in longitude, have plasma properties that seem to bridge the gap b…
Atmospheric photochemistry above possible martian hot spots
Atreya, S. K.; Ignatiev, N. I.; Formisano, V. +2 more
Considering the possibility of outgassing from some localized sources on Mars, we have developed a one-dimensional photochemical model that includes methane (CH4), sulfur dioxide (SO2) and hydrogen sulfide (H2S). Halogens were considered but were found to have no significant impact on the martian atmospheric chemis…