Search Publications
Earth's Bow Shock: A New Three-Dimensional Asymmetric Model With Dipole Tilt Effects
Wang, M.; Ma, X.; Zhou, Y. +3 more
Using the bow shock crossing events from four spacecraft: IMP 8, Geotail, Magion-4, and Cluster 1, a new three-dimensional asymmetric bow shock model is constructed. The model is parameterized by the solar wind dynamic pressure, the interplanetary magnetic field, magnetosonic Mach number, solar wind β, and the Earth's dipole tilt angle. It is show…
The Structure of Planetary Period Oscillations in Saturn's Equatorial Magnetosphere: Results From the Cassini Mission
Wahlund, J. -E.; Andrews, D. J.; Cowley, S. W. H. +4 more
Saturn's magnetospheric magnetic field, planetary radio emissions, plasma populations, and magnetospheric structure are all known to be modulated at periods close to the assumed rotation period of the planetary interior. These oscillations are readily apparent despite the high degree of axisymmetry in the internally produced magnetic field of the …
The mid-infrared and CO gas properties of an extreme star-forming FeLoBAL quasar
Lacy, Mark; Hatziminaoglou, Evanthia; Afonso, José +6 more
We present a detailed study of a high-redshift iron low-ionization broad absorption line (FeLoBAL) quasar (SDSS1214 at z = 1.046), including new interferometric 12CO J = 2-1 observations, optical through far-infrared photometry, and mid-infrared spectroscopy. The CO line is well fit by a single Gaussian centred 40 km s-1 away…
Using Ghost Fronts Within STEREO Heliospheric Imager Data to Infer the Evolution in Longitudinal Structure of a Coronal Mass Ejection
de Koning, C. A.; Owens, M. J.; Scott, C. J. +3 more
Images of coronal mass ejections (CMEs) from the Heliospheric Imager instruments on board the Solar Terrestrial Relations Observatory (STEREO) spacecraft frequently contain rich structure. Here, we present analysis of the Earth-directed CME launched on 12 December 2008 in which we interpret the revealed structure as projections of separate discret…
Formation and Eruption of Sigmoidal Structure from a Weak Field Region of NOAA 11942
Ravindra, B.; Doddamani, V. H.; Vemareddy, P. +1 more
Using observations from the Solar Dynamics Observatory, we studied an interesting example of a sigmoid formation and eruption from small-scale flux-canceling regions of active region (AR) 11942. Through an analysis of Helioseismic and Magnetic Imager and Atmospheric Imaging Assembly observations we infer that initially the AR is compact and bipola…
The coronal temperature of NGC 4388 and NGC 2110 measured with INTEGRAL
Bird, A. J.; Ubertini, P.; Malizia, A. +4 more
Aims: We aim to measure the physical properties of the hot X-ray corona of two active galactic nuclei, NGC 4388 and NGC 2110.
Methods: We analysed the hard X-ray (20-300 keV) INTEGRAL spectrum in conjunction with archival XMM-Newton and NuSTAR data.
Results: The X-ray spectrum of both sources is phenomenologically well described by …
Observations of the Ultra-compact X-Ray Binary 4U 1543-624 in Outburst with NICER, INTEGRAL, Swift, and ATCA
Altamirano, D.; Fabian, A. C.; Miller, J. M. +17 more
We report on X-ray and radio observations of the ultra-compact X-ray binary 4U 1543-624 taken in August 2017 during an enhanced accretion episode. We obtained Neutron Star Interior Composition Explorer (NICER) monitoring of the source over a ∼10 day period during which target-of-opportunity observations were also conducted with Swift, INTErnationa…
A Study of the 20 day Superorbital Modulation in the High-mass X-Ray Binary IGR J16493-4348
Fürst, Felix; Pottschmidt, Katja; Corbet, Robin H. D. +4 more
We report on Nuclear Spectroscopic Telescope Array (NuSTAR), Neil Gehrels Swift Observatory (Swift) X-ray Telescope (XRT), and Swift Burst Alert Telescope (BAT) observations of IGR J16493-4348, a wind-fed supergiant X-ray binary showing significant superorbital variability. From a discrete Fourier transform of the BAT light curve, we refine its su…
A far-UV survey of three hot, metal-polluted white dwarf stars: WD0455-282, WD0621-376, and WD2211-495
Webb, John K.; Lee, Chung-Chi; Reindl, Nicole +7 more
Using newly obtained high-resolution data (R ∼ 1 × 105) from the Hubble Space Telescope, and archival UV data from the Far Ultraviolet Spectroscopic Explorer, we have conducted a detailed UV survey of the three hot, metal-polluted white dwarfs WD0455-282, WD0621-376, and WD2211-495. Using bespoke model atmospheres, we measured Teff…
An investigation of C, N, and Na abundances in red giant stars of the Sculptor dwarf spheroidal galaxy
Da Costa, G. S.; Yong, D.; Norris, J. E. +1 more
The origin of the star-to-star abundance variations found for the light elements in Galactic globular clusters (GGCs) is not well understood, which is a significant problem for stellar astrophysics. While the light element abundance variations are very common in globular clusters, they are comparatively rare in the Galactic halo field population. …