Search Publications
Hydrogen Column Density Evaluations toward Capella: Consequences on the Interstellar Deuterium Abundance
Ferlet, R.; Vidal-Madjar, A.
The deuterium abundance evaluation in the direction of Capella has for a long time been used as a reference for the local interstellar medium (ISM) within our Galaxy. We show here that broad and weak H I components could be present on the Capella line of sight, leading to a large new additional systematic uncertainty on the N(H I) evaluation. We f…
A 2.4-12 mu m spectrophotometric study with ISO of Cygnus X-3 in quiescence
Ábrahám, P.; Fuchs, Y.; Koch-Miramond, L. +2 more
We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray binary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4-12 mu m continuum radiation observed with ISOPHOT-S can be explained by thermal free-free emission in an expanding wind with, above 6.5 mu m, a possible additional black-body compon…
Identifying Gamma-Ray Burst Remnants through Positron Annihilation Radiation
Loeb, Abraham; Furlanetto, Steven R.
We model the annihilation of relic positrons produced in a gamma-ray burst (GRB) after its afterglow has faded. We find that the annihilation signal from at least one GRB remnant in the Milky Way should be observable with future space missions such as the International Gamma-Ray Astrophysical Laboratory and the Energetic X-ray Imaging Survey Teles…
Statistical Relationships between Solar, Interplanetary, and Geomagnetospheric Disturbances, 1976-2000
Yermolaev, Yu. I.; Yermolaev, M. Yu.
Within the framework of the Space Weather program, 25-year data sets for solar X-ray observations, measurements of plasma and magnetic field parameters in the solar wind, and D_st index variations are analyzed to reveal the factors that have had the greatest influence on the development of magnetospheric storms. The correlation between solar flare…
Relation between Pressure Balance Structures and polar plumes from Ulysses high latitude observations
Sakurai, Takashi; Suess, Steven T.; Yamauchi, Yohei
Ulysses observations have shown that pressure balance structures (PBSs) are a common feature in high-latitude, fast solar wind near solar minimum. Previous studies of Ulysses/SWOOPS plasma data suggest these PBSs may be remnants of coronal polar plumes. Here we find support for this suggestion in an analysis of PBS magnetic structure. We used Ulys…
Structure and evolution of FK Comae corona
Gondoin, P.; Lumb, D.; Erd, C.
FK Comae (HD 117555) is a rapidly rotating single G giant whose distinctive characteristics include a quasisinusoidal optical light curve and high X-ray luminosity. FK Comae was observed twice at two weeks interval in January 2001 by the XMM-Newton space observatory. Analysis results suggest a scenario where the corona of FK Comae is dominated by …
Westphal-MMD 11: An Interacting, Submillimeter Luminous Lyman Break Galaxy
Chapman, S. C.; Shapley, A.; Windhorst, R. +1 more
We present new Hubble Space Telescope, high-resolution optical imaging of the submillimeter luminous Lyman break galaxy (LBG), Westphal-MMD 11, an interacting starburst at z=2.979. The new imaging data, in conjunction with reanalysis of Keck optical and near-IR spectra, demonstrate MMD 11 to be an interacting system of at least three components: a…
An analysis of STIS HST UV spectra of M 33 early B supergiants
Kudritzki, R. P.; Herrero, A.; Bresolin, F. +3 more
We present terminal velocities of M 33 B-supergiants, obtained from STIS HST spectra as part of our programme to investigate the Wind Momentum - Luminosity Relationship (WLR) in the Local Group. Terminal velocities are derived from their N V, C Iv, and Si Iv resonance lines in UV spectra. Comparing with IUE spectra of Galactic B-supergiants we fou…
The X-ray afterglow of GRB 020322
Ehle, M.; Watson, D.; O'Brien, P. T. +4 more
The spectrum of the afterglow of GRB 020322 is the highest-quality X-ray spectrum of a GRB afterglow available to date. It was detected by XMM-Newton in an observation starting fifteen hours after the GRB with a mean 0.2-10.0 keV observed flux of 3.5+/-0.2*E-13 erg cm-2 s-1, making it the brightest X-ray afterglow …
Effects of Temperature Bias on Nanoflare Statistics
Aschwanden, Markus J.; Charbonneau, Paul
Statistics of solar flares, microflares, and nanoflares have been gathered over an energy range of some 8 orders of magnitude, over E~1024-1032 ergs. Frequency distributions of flare energies are always determined in a limited temperature range, e.g., at T~1-2 MK if the 171 and 195 Å filters are used from an extreme ultraviol…