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A Study of the Elements Copper through Uranium in Sirius A: Contributions from STIS and Ground-Based Spectra
Wahlgren, G. M.; Castelli, F.; Monier, R. +3 more
We determine abundances or upper limits for all of the 55 stable elements from copper to uranium for the A1 Vm star Sirius. The purpose of the study is to assemble the most complete picture of elemental abundances with the hope of revealing the chemical history of the brightest star in the sky, apart from the Sun. We also explore the relationship …
Swift J174540.7-290015: a new accreting binary in the Galactic Centre
Haberl, F.; Ponti, G.; Rea, N. +8 more
We report on the identification of the new Galactic Centre (GC) transient Swift J174540.7-290015 as a likely low-mass X-ray binary located at only 16 arcsec from Sgr A⋆. This transient was detected on 2016 February 6, during the Swift GC monitoring, and it showed long-term spectral variations compatible with a hard- to soft-state transi…
A Deep Chandra ACIS Survey of M51
Kuntz, K. D.; Long, Knox S.; Kilgard, Roy E.
We have obtained a deep X-ray image of the nearby galaxy M51 using Chandra. Here we present the catalog of X-ray sources detected in these observations and provide an overview of the properties of the point-source population. We find 298 sources within the D 25 radii of NGC 5194/5, of which 20% are variable, a dozen are classical transi…
Narrowband Gyrosynchrotron Bursts: Probing Electron Acceleration in Solar Flares
Kontar, Eduard P.; Fleishman, Gregory D.; Nita, Gelu M. +1 more
Recently, in a few case studies we demonstrated that gyrosynchrotron microwave emission can be detected directly from the acceleration region when the trapped electron component is insignificant. For the statistical study reported here, we have identified events with steep (narrowband) microwave spectra that do not show a significant trapped compo…
First in situ evidence of electron pitch angle scattering due to magnetic field line curvature in the Ion diffusion region
Lavraud, B.; Liu, Z. X.; Rong, Z. J. +8 more
Theory predicts that the first adiabatic invariant of a charged particle may be violated in a region of highly curved field lines, leading to significant pitch angle scattering for particles whose gyroradius are comparable to the radius of the magnetic field line curvature. This scattering generates more isotropic particle distribution functions, …
Star formation and AGN activity in the most luminous LINERs in the local universe
Pérez, Enrique; Netzer, Hagai; Pović, Mirjana +4 more
This work presents the properties of 42 objects in the group of the most luminous, highest star formation rate (SFR) low-ionization nuclear emission-line regions (LINERs) at z = 0.04-0.11. We obtained long-slit spectroscopy of the nuclear regions for all sources, and FIR data (Herschel and IRAS) for 13 of them. We measured emission-line intensitie…
Analysis of Flows inside Quiescent Prominences as Captured by Hinode/Solar Optical Telescope
Longcope, D. W.; McKenzie, D. E.; Freed, M. S. +1 more
Developing an understanding of how magnetic fields can become entangled in a prominence is important for predicting a possible eruption. This work investigates the kinetic energy and vorticity associated with plasma motion residing inside quiescent prominences (QPs). These plasma flow characteristics can be utilized to improve our understanding of…
Association of 3He-Rich Solar Energetic Particles with Large-scale Coronal Waves
Mason, Glenn M.; Bučík, Radoslav; Wiedenbeck, Mark E. +1 more
Small, 3He-rich solar energetic particle (SEP) events have been commonly associated with extreme-ultraviolet (EUV) jets and narrow coronal mass ejections (CMEs) that are believed to be the signatures of magnetic reconnection, involving field lines open to interplanetary space. The elemental and isotopic fractionation in these events are…
Relationship Between Chromospheric Evaporation and Magnetic Field Topology in an M-Class Solar Flare
Kosovichev, Alexander G.; Sadykov, Viacheslav M.; Sharykin, Ivan N. +2 more
Chromospheric evaporation is observed as Doppler blueshift during solar flares. It plays a key role in the dynamics and energetics of solar flares; however, its mechanism is still unknown. In this paper, we present a detailed analysis of spatially resolved multi-wavelength observations of chromospheric evaporation during an M 1.0-class solar flare…
Models of the η Corvi Debris Disk from the Keck Interferometer, Spitzer, and Herschel
Bryden, G.; Lebreton, J.; Boccaletti, A. +4 more
Debris disks are signposts of analogs to small-body populations of the solar system, often, however, with much higher masses and dust production rates. The disk associated with the nearby star η Crv is especially striking, as it shows strong mid- and far-infrared excesses despite an age of ∼1.4 Gyr. We undertake constructing a consistent model of …