Search Publications
No evidence for an Eddington-ratio dependence of X-ray weakness in BALQSOs
Brandt, W. N.; Vignali, C.; Gilli, R. +3 more
Several works have studied the relation between X-ray, ultraviolet (UV), and wind properties in broad absorption line quasars (BALQSOs), generally concluding that the formation of strong winds is tightly connected with the suppression of the ionizing extreme ultraviolet (EUV)/X-ray emission. The Eddington ratio (λEdd), which measures th…
Revealing the Evolution of Non-thermal Electrons in Solar Flares Using 3D Modeling
Fleishman, Gregory D.; Nita, Gelu M.; Kuroda, Natsuha +4 more
Understanding non-thermal particle generation, transport, and escape in solar flares requires detailed quantification of the particle evolution in the realistic 3D domain where the flare takes place. Rather surprisingly, apart from the standard flare scenario and integral characteristics of non-thermal electrons, not much is known about the actual…
Variability of extragalactic sources: its contribution to the link between ICRF and the future Gaia Celestial Reference Frame
Souchay, J.; Taris, F.; Andrei, A. +3 more
Context. The first release of the Gaia catalog is available since 14 September 2016. It is a first step in the realization of the future Gaia reference frame. This reference frame will be materialized by the optical positions of the sources and will be compared with and linked to the International Celestial Reference Frame, materialized by the rad…
Properties of a Small-scale Short-duration Solar Eruption with a Driven Shock
Feng, Li; Lu, Lei; Gan, Weiqun +5 more
Large-scale solar eruptions have been extensively explored over many years. However, the properties of small-scale events with associated shocks have rarely been investigated. We present analyses of a small-scale, short-duration event originating from a small region. The impulsive phase of the M1.9-class flare lasted only four minutes. The kinemat…
Empirical Modeling of the Quiet and Storm Time Geosynchronous Magnetic Field
Tsyganenko, N. A.; Andreeva, V. A.
A dynamical empirical model of the near-geosynchronous magnetic field has been constructed, based on a recently developed radial basis functions approach and a multiyear set of spacecraft data taken by Time History of Events and Macroscale Interactions during Substorms (THEMIS), Polar, Cluster, and Van Allen Probes missions including 133 geomagnet…
Heliospheric Conditions at Saturn During Cassini's Ring-Grazing and Proximal Orbits
Krupp, N.; Jackman, C. M.; Roussos, E. +6 more
We surveyed energetic charged particle measurements by Cassini between 2016 and the end of the mission in order to identify transients of solar energetic particles and galactic cosmic rays. Such transients offer hints about the state of the heliosphere and valuable context for interpreting space weather phenomena in Saturn's magnetosphere. The per…
Detection of [O III] at z ∼ 3: A Galaxy Above the Main Sequence, Rapidly Assembling Its Stellar Mass
Menten, Karl M.; Güsten, Rolf; Weiss, Axel +8 more
We detect bright emission in the far-infrared (far-IR) fine structure [O III] 88 µm line from a strong lensing candidate galaxy, H-ATLAS J113526.3-014605, hereafter G12v2.43, at z = 3.127, using the second-generation Redshift (z) and Early Universe Spectrometer (ZEUS-2) at the Atacama Pathfinder Experiment Telescope (APEX). This is only the …
Magnetic Helicity Reversal in the Corona at Small Plasma Beta
Brandenburg, Axel; Bourdin, Philippe; Singh, Nishant K.
Solar and stellar dynamos shed small-scale and large-scale magnetic helicity of opposite signs. However, solar wind observations and simulations have shown that some distance above the dynamo both the small-scale and large-scale magnetic helicities have reversed signs. With realistic simulations of the solar corona above an active region now being…
Glimpse of the highly obscured HMXB IGR J16318-4848 with Hitomi
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +191 more
We report on a Hitomi observation of IGR J16318-4848, a high-mass X-ray binary system with an extremely strong absorption of NH ∼ 1024 cm-2. Previous X-ray studies revealed that its spectrum is dominated by strong fluorescence lines of Fe as well as continuum emission lines. For physical and geometrical insight int…
Velocity-resolved [{\rm{C}}\,{\rm{II}}] Emission from Cold Diffuse Clouds in the Interstellar Medium
Neufeld, David A.; Wolfire, Mark G.; Simon, Robert +3 more
We have combined emission from the 158 µm fine structure transition of C+ observed with the GREAT and upGREAT instruments on SOFIA with 21 cm absorption spectra and visual extinction to characterize the diffuse interstellar clouds found along the lines of sight. The weak [C II] emission is consistent in velocity and line width wit…