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Spectral analysis of the dipping LMXB system XB 1916-053
Sanna, A.; Di Salvo, T.; Burderi, L. +6 more
Context. XB 1916-053 is a low mass X-ray binary system (LMXB) hosting a neutron star (NS) and showing periodic dips. The spectrum of the persistent emission was modeled with a blackbody component having a temperature between 1.31 and 1.67 keV and with a Comptonization component with an electron temperature of 9.4 keV and a photon index Γ between 2…
Saturn's Plasmapause: Signature of Magnetospheric Dynamics
Coates, A. J.; Thomsen, M. F.
We explore the paradigm that Saturn's plasmapause marks the boundary between the magnetic flux tubes that have been circulating around the planet for some time, accumulating a dense load of Enceladus-sourced material, and those that have recently undergone tail reconnection, shedding the bulk of the cold plasma and retaining a more tenuous, heated…
Photometry and Spectroscopy of Faint Candidate Spectrophotometric Standard DA White Dwarfs
Rest, Armin; Matheson, Thomas; Points, Sean +14 more
We present precise photometry and spectroscopy for 23 candidate spectrophotometric standard white dwarfs. The selected stars are distributed in the Northern hemisphere and around the celestial equator, and are all fainter than r ∼ 16.5 mag. This network of stars, when established as standards and together with the three Hubble Space Telescope prim…
MCMC Inversion of Stokes Profiles
Sun, Leilei; Xu, Zhi; Li, Hao +1 more
Stokes inversion techniques, based on the analysis of the polarization in spectral lines, are the most powerful tools to obtain the information about the magnetic and thermodynamic quantities in the solar atmosphere. In this paper, we present a Milne-Eddington inversion code based on Bayesian inference, which is implemented with the Markov chain M…
The relativistic jet of the γ-ray emitting narrow-line Seyfert 1 galaxy PKS J1222+0413
Done, Chris; Angelakis, Emmanouil; Landt, Hermine +6 more
We present a multifrequency study of PKS J1222+0413 (4C +04.42), currently the highest redshift γ-ray emitting narrow-line Seyfert 1 (γ-NLS1). We assemble a broad spectral energy distribution (SED) including previously unpublished datasets: X-ray data obtained with the NuSTAR and Neil Gehrels Swift observatories; near-infrared, optical, and UV spe…
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…