Search Publications
Missions
Journals
Publication Years
Probing Wolf-Rayet Winds: Chandra/HETG X-Ray Spectra of WR 6
Hamann, W. -R.; Huenemoerder, David P.; Ignace, R. +6 more
With a deep Chandra/HETGS exposure of WR 6, we have resolved emission lines whose profiles show that the X-rays originate from a uniformly expanding spherical wind of high X-ray-continuum optical depth. The presence of strong helium-like forbidden lines places the source of X-ray emission at tens to hundreds of stellar radii from the photosphere. …
The WISE Light Curves of Polars
Harrison, Thomas E.; Campbell, Ryan K.
We have extracted the WISE (Wide-field Infrared Survey Explorer) single-exposure data for a sample of 72 polars, which are highly magnetic cataclysmic variables (CVs). We combine these data with both published and unpublished optical and infrared data to explore the origins of the large amplitude variations seen in these systems. In nearly every c…
Gamma-ray activity of Seyfert galaxies and constraints on hot accretion flows
Szanecki, Michał; Niedźwiecki, Andrzej; Xie, Fu-Guo +1 more
Aims: We check how the Fermi/LAT data constrain the physics of hot accretion flows that are most likely present in low-luminosity AGNs.
Methods: Using a precise model of emission from hot flows, we studied the flow γ-ray emission resulting from proton-proton interactions. We explored the dependence of the γ-ray luminosity on the accretio…
Disentangling the jet emission from protostellar systems. The ALMA view of VLA1623
Codella, C.; van Dishoeck, E. F.; Bruderer, S. +4 more
Context. High-resolution studies of class 0 protostars represent the key to constraining protostar formation models. VLA16234-2417 represents the prototype of class 0 protostars, and it has been recently identified as a triple non-coeval system.
Aims: We aim at deriving the physical properties of the jets in VLA16234-2417 using tracers of sho…
Seasonal changes in Saturn's stratosphere inferred from Cassini/CIRS limb observations
Flasar, F. M.; Spiga, A.; Fouchet, T. +4 more
We present temperature and hydrocarbons abundances (C2H6, C2H2, C3H8) retrieved from Cassini/CIRS limb spectra, acquired during northern spring in 2010 (LS = 12 °) and 2012 (LS = 31 °). We compare them to the previous limb measurements performed by Guerlet et a…
Evolution of stratospheric chemistry in the Saturn storm beacon region
Fletcher, Leigh N.; Irwin, Patrick G. J.; Moses, Julianne I. +4 more
The giant northern-hemisphere storm that erupted on Saturn in December 2010 triggered significant changes in stratospheric temperatures and species abundances that persisted for more than a year after the original outburst. The stratospheric regions affected by the storm have been nicknamed "beacons" due to their prominent infrared-emission signat…
Generation of large-scale magnetic fields, non-Gaussianity, and primordial gravitational waves in inflationary cosmology
Bamba, Kazuharu
The generation of large-scale magnetic fields in inflationary cosmology is explored, in particular, in a kind of moduli inflation motivated by racetrack inflation in the context of the type IIB string theory. In this model, the conformal invariance of the hypercharge electromagnetic fields is broken thanks to the coupling of both the scalar and ps…
A statistical analysis of Pi2-band waves in the plasma sheet and their relation to magnetospheric drivers
Zhang, T. L.; Nakamura, R.; Baumjohann, W. +5 more
We use the Cluster data from 2001 to 2009 to investigate the occurrence of Pi2-band waves in the plasma sheet. To study the generation mechanisms of these waves, we examine the association between Pi2-band waves and dynamic processes in the plasma sheet (fast flows and substorm activity) and the direction of the solar wind velocity. For a total of…
The interaction between ULF waves and thermal plasma ions at the plasmaspheric boundary layer during substorm activity
Ren, J.; Zong, Q. G.; Wang, Y. F. +1 more
During a substorm on 27 January 2004, energetic particle injections associated with ULF waves have been detected when Cluster fleet was traveling inbound in the Southern Hemisphere. Substorm-injected energetic particles are strong and clearly modulated by these ULF waves. The ULF waves with the period of 1 min are probably the third harmonic mode.…
NGC 6139: a normal massive globular cluster, or a first-generation dominated cluster? Clues from the light elements
Bragaglia, A.; D'Orazi, V.; Sneden, C. +5 more
Information on globular clusters (GC) formation mechanisms can be gathered by studying the chemical signature of the multiple populations that compose these stellar systems. In particular, we investigate the anti-correlations among O, Na, Al, and Mg to explore the influence of cluster mass and environment on GCs in the Milky Way and in extragalact…