Search Publications
Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS
Mason, H. E.; Del Zanna, G.; Reeves, K. K. +3 more
The intensity of the O iv 2s2 2p 2P-2s2p24P and S iv 3 s2 3p 2P-3s 3p24 P intercombination lines around 1400 Å observed with the Interface Region Imaging Spectrograph (IRIS) provide a useful tool to diagnose the electron number density (Ne) in the so…
Fan-shaped jets above the light bridge of a sunspot driven by reconnection
Rouppe van der Voort, Luc; Leenaarts, Jorrit; Robustini, Carolina +1 more
We report on a fan-shaped set of high-speed jets above a strongly magnetized light bridge (LB) of a sunspot observed in the Hα line. We study the origin, dynamics, and thermal properties of the jets using high-resolution imaging spectroscopy in Hα from the Swedish 1m Solar Telescope and data from the Solar Dynamics Observatory and Hinode. The Hα j…
Measuring the stellar wind parameters in IGR J17544-2619 and Vela X-1 constrains the accretion physics in supergiant fast X-ray transient and classical supergiant X-ray binaries
Sander, A.; Hamann, W. -R.; Shenar, T. +9 more
Context. Classical supergiant X-ray binaries (SGXBs) and supergiant fast X-ray transients (SFXTs) are two types of high-mass X-ray binaries (HMXBs) that present similar donors but, at the same time, show very different behavior in the X-rays. The reason for this dichotomy of wind-fed HMXBs is still a matter of debate. Among the several explanation…
The F-GAMMA programme: multi-frequency study of active galactic nuclei in the Fermi era. Programme description and the first 2.5 years of monitoring
Pearson, T. J.; Nestoras, I.; Zensus, J. A. +15 more
Context. To fully exploit the scientific potential of the Fermi mission for the physics of active galactic nuclei (AGN), we initiated the F-GAMMA programme. Between 2007 and 2015 the F-GAMMA was the prime provider of complementary multi-frequency monitoring in the radio regime.
Aims: We quantify the radio variability of γ-ray blazars. We inve…
Timing the warm absorber in NGC 4051
Costantini, E.; Uttley, P.; Silva, C. V.
We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results of the extensive 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051 whose spectrum has revealed a complex multicomponent…
Subarcsecond international LOFAR radio images of Arp 220 at 150 MHz. A kpc-scale star forming disk surrounding nuclei with shocked outflows
Beswick, R.; Gallagher, J. S.; Horellou, C. +16 more
Context. Arp 220 is the prototypical ultra luminous infrared galaxy (ULIRG). Despite extensive studies, the structure at MHz-frequencies has remained unknown because of limits in spatial resolution.
Aims: This work aims to constrain the flux and shape of radio emission from Arp 220 at MHz frequencies.
Methods: We analyse new observations…
Plasma code for astrophysical charge exchange emission at X-ray wavelengths
Raassen, A. J. J.; Gu, Liyi; Kaastra, Jelle
Charge exchange X-ray emission provides unique insight into the interactions between cold and hot astrophysical plasmas. Besides its own profound science, this emission is also technically crucial to all observations in the X-ray band, since charge exchange with the solar wind often contributes a significant foreground component that contaminates …
Aswan site on comet 67P/Churyumov-Gerasimenko: Morphology, boulder evolution, and spectrophotometry
Bertaux, Jean-Loup; Da Deppo, Vania; Naletto, Giampiero +49 more
Aims: We provide a detailed morphological analysis of the Aswan site on comet 67P/Churyumov-Gerasimenko (67P). We derive the size-frequency distribution of boulders ≥2 m and correlate this distribution with the gravitational slopes for the first time on a comet. We perform the spectral analysis of this region to understand if possible surface…
A milestone toward understanding PDR properties in the extreme environment of LMC-30 Doradus
Lebouteiller, V.; Madden, S. C.; Galliano, F. +11 more
Context. More complete knowledge of galaxy evolution requires understanding the process of star formation and the interaction between the interstellar radiation field and interstellar medium (ISM) in galactic environments traversing a wide range of physical parameter space. We focus on the impact of massive star formation on the surrounding low me…
Magnetic field morphology in nearby molecular clouds as revealed by starlight and submillimetre polarization
Miville-Deschênes, M. -A.; Boulanger, F.; Falgarone, E. +8 more
Within four nearby (d < 160 pc) molecular clouds, we statistically evaluated the structure of the interstellar magnetic field, projected on the plane of the sky and integrated along the line of sight, as inferred from the polarized thermal emission of Galactic dust observed by Planck at 353 GHz and from the optical and near-infrared polarizatio…