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Stellar laboratories. V. The Xe vi ultraviolet spectrum and the xenon abundance in the hot DO-type white dwarf RE 0503-289
Hoyer, D.; Rauch, T.; Quinet, P. +2 more
Context. For the spectral analysis of spectra of hot stars with a high resolution and high signal-to-noise ratio (S/N), advanced non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that are used for their calculation.
Aims: Reliable Xe vi oscillator str…
Quasi-periodic oscillations in accreting magnetic white dwarfs. I. Observational constraints in X-ray and optical
Bonnet-Bidaud, J. M.; Mouchet, M.; Busschaert, C. +2 more
Quasi-periodic oscillations (QPOs) are observed in the optical flux of some polars with typical periods of 1 to 3 s but none have been observed yet in X-rays where a significant part of the accreting energy is released. QPOs are expected and predicted from shock oscillations. Most of the polars have been observed by the XMM-Newton satellite. We ma…
Low frequency radio observations of bi-directional electron beams in the solar corona
Gallagher, Peter T.; Carley, Eoin P.; Vilmer, Nicole +1 more
The radio signature of a shock travelling through the solar corona is known as a type II solar radio burst. In rare cases these bursts can exhibit a fine structure known as "herringbones", which are a direct indicator of particle acceleration occurring at the shock front. However, few studies have been performed on herringbones and the details of …
Spectrum of Relativistic and Subrelativistic Cosmic Rays in the 100 pc Central Region
Cheng, K. S.; Hui, C. Y.; Nobukawa, M. +6 more
From the rate of hydrogen ionization and the gamma-ray flux, we derived the spectrum of relativistic and subrelativistic cosmic rays (CRs) nearby and inside the molecular cloud Sgr B2 near the Galactic Center. We studied two cases of CR propagation in molecular clouds: free propagation and scattering of particles by magnetic fluctuations excited b…
Rotational temperatures of Venus upper atmosphere as measured by SOIR on board Venus Express
Vandaele, A. C.; Robert, S.; Wilquet, V. +6 more
SOIR is a powerful infrared spectrometer flying on board the Venus Express spacecraft since mid-2006. It sounds the Venus atmosphere above the cloud layer using the solar occultation technique. In the recorded spectra, absorption structures from many species are observed, among them carbon dioxide, the main constituent of the Venus atmosphere. Pre…
Panchromatic Hubble Andromeda Treasury. XIV. The Period-Age Relationship of Cepheid Variables in M31 Star Clusters
Williams, Benjamin F.; Johnson, L. Clifton; Dolphin, Andrew +6 more
We present a sample of 11 M31 Cepheids in stellar clusters, derived from the overlap of the Panchromatic Hubble Andromeda Treasury cluster catalog and the Pan-STARRS1 (PS1) disk Cepheid catalog. After identifying the PS1 Cepheids in the Hubble Space Telescope (HST) catalog, we calibrate the PS1 mean magnitudes using the higher resolution HST photo…
Evolution of Small-Scale Magnetic Elements in the Vicinity of Granular-Sized Swirl Convective Motions
Vargas Domínguez, S.; Balmaceda, L.; Domingo, V. +2 more
Advances in solar instrumentation have led to widespread use of time series to study the dynamics of solar features, especially at small spatial scales and at very fast cadences. Physical processes at such scales are important as building blocks for many other processes occurring from the lower to the upper layers of the solar atmosphere and beyon…
High-energy emission processes in M87
Tramacere, A.; Beckmann, V.; Soldi, S. +2 more
We study the contribution of thermal and non-thermal processes to the inverse Compton emission of the radio galaxy M87 by modelling its broad-band emission. Through this we aim to derive insight into where within the AGN the X-ray, γ-ray and VHE emission is produced. We have analysed all available INTEGRAL IBIS/ISGRI (Imager on Board INTEGRAL Spac…
High spectral and spatial resolution observations of the PDR emission in the NGC 2023 reflection nebula with SOFIA and APEX
Okada, Y.; Güsten, R.; Requena-Torres, M. A. +3 more
We have mapped the NGC 2023 reflection nebula in [C ii] and CO(11-10) with the heterodyne receiver GREAT on SOFIA and obtained slightly smaller maps in 13CO(3-2), CO(3-2), CO(4-3), CO(6-5), and CO(7-6) with APEX in Chile. We use these data to probe the morphology, kinematics, and physical conditions of the C ii region, which is ionized …
Relativistic Fe Kα line revealed in the composite X-ray spectrum of narrow-line Seyfert 1 galaxies - do their black holes have averagely low or intermediate spins?
Lu, Youjun; Liu, Zhu; Yuan, Weimin +1 more
While a broad profile of the Fe Kα emission line is frequently found in the X-ray spectra of typical Seyfert galaxies, the situation is unclear in the case of narrow-line Seyfert 1 galaxies (NLS1s) - an extreme subset which are generally thought to harbour less massive black holes with higher accretion rates. In this paper, the ensemble property o…