Search Publications

Long slit spectropolarimetry of Jupiter and Saturn

Buenzli, E.; Schmid, H. M.; Gisler, D. +1 more

We present ground-based limb polarization measurements of Jupiter and Saturn consisting of full disk imaging polarimetry for the wavelength 7300 Å and spatially resolved (long-slit) spectropolarimetry covering the wavelength range 5200-9350 Å. For the polar region of Jupiter we find for λ = 6000 Å a very strong radial (perpendicular to the limb) f…

The Hubble Space Telescope colours of high-redshift Population III galaxies with strong Lyα emission

Inoue, Akio K.; Rydberg, Claes-Erik; Zackrisson, Erik +1 more

Population III (pop III) galaxies, made partly or exclusively of metal-free stars, are predicted to exist at high redshifts and may produce very strong Lyα emission. A substantial fraction of these Lyα photons are likely absorbed in the intergalactic medium at z > 6, but recent simulations suggest that significant Lyα emission may be detectable…

Nova M31N 2007-12b: supersoft X-rays reveal an intermediate polar?

Della Valle, M.; Pietsch, W.; Haberl, F. +4 more

Context. In the central part of M 31, a high number of optical novae can be targeted within the field of view of the XMM-Newton EPIC and Chandra HRC-I X-ray detectors. A special monitoring program of the area has allowed us to investigate supersoft emission of individual novae in detail and perform a statistical analysis of the …

Unusual electron density profiles observed by Cassini radio occultations in Titan's ionosphere: Effects of enhanced magnetospheric electron precipitation?

Cravens, T. E.; Rymer, A. M.; Richard, M. S. +2 more

The Cassini radio science facility provided 13 occultation electron density profiles of Titan during the period of 2006 and 2009. This paper presents the results of all of these occultation observations. It shows that ten of the observed electron density profiles are similar, but three are significantly different. The number of observations is rel…

Suzaku Observations of the Prototype Wind-blown Bubble NGC 6888

Zhekov, Svetozar A.; Park, Sangwook

We present an analysis of the Suzaku observations of the prototype wind-blown bubble NGC 6888 which is based both on use of standard spectral models and on a direct comparison of theoretical models with observations. The X-ray spectra of NGC 6888 are soft and most of the X-rays are in the 0.3-1.5 keV energy range. But, hard X-rays (1.5-4.0 keV) ar…

The Interplanetary Network Supplement to the Burst and Transient Source Experiment 5B Catalog of Cosmic Gamma-Ray Bursts

Cline, T.; Hurley, K.; Kouveliotou, C. +10 more

We present Interplanetary Network localization information for 343 gamma-ray bursts observed by the Burst and Transient Source Experiment (BATSE) between the end of the 4th BATSE catalog and the end of the Compton Gamma-Ray Observatory (CGRO) mission, obtained by analyzing the arrival times of these bursts at the Ulysses, Near Earth Asteroid Rende…

Jet front-driven mirror modes and shocklets in the near-Earth flow-braking region

Retinò, Alessandro; Khotyaintsev, Yuri; Vaivads, Andris +3 more

We investigate the small-scale structure of jet fronts through a case study of multi-spacecraft Cluster observations in the near-Earth flow-braking region at ∼-10 R_E. We find that the interaction between the earthward moving fast plasma jet and the high-β ambient plasma in the plasma sheet results in magnetic pileup and compression ahea…

Geology of possible Martian methane source regions

Ehlmann, Bethany L.; Wray, James J.

Recent observations of methane on Mars suggest that spatially localized source regions are present. Here we discuss the surface morphology and mineralogy of these regions, focusing on features that may provide insights into mechanisms of methane production and/or release. Preliminary trends among methane source regions include old age, deep fractu…

On the source of dense outflows from T Tauri stars - III. Winds driven from the star-disc shear layer

Gómez de Castro, Ana I.; von Rekowski, Brigitta

Ultraviolet observations of classical T Tauri Stars (cTTSs) have shown that there is a hot (T_e≃ 80 000 K) and dense (n_e≃ 10¹⁰ cm^-3) component associated with the large-scale jet. This hot component is formed very close to the base of the jet providing fundamental information on the jet formation mechanis…

On the association of ULXs with young superclusters: M82 X-1 and a new candidate in NGC 7479

Smartt, S. J.; Nelemans, G.; Fraser, M. +2 more

We investigate the spatial coincidence of ultraluminous X-ray sources (ULXs) with young massive stellar clusters. In particular, we perform astrometry on Chandra and Hubble Space Telescope (HST) data of two ULXs that are possibly associated with such clusters.

To date, M82 X-1 is the only ULX claimed to be coincident with a young massive stel…