Search Publications
Magnetic Doppler imaging of the chemically peculiar star HD 125248
Ilyin, I.; Ryabchikova, T.; Kochukhov, O. +1 more
Context. Intermediate-mass, chemically peculiar stars with strong magnetic fields provide an excellent opportunity to study the topology of their surface magnetic fields and the interplay between magnetic geometries and abundance inhomogeneities in the atmospheres of these stars.
Aims: We reconstruct detailed maps of the surface magnetic fiel…
Coronal mass ejection-related particle acceleration regions during a simple eruptive event
Rouillard, Alexis P.; Klein, Karl-Ludwig; Salas-Matamoros, Carolina
An intriguing feature of many solar energetic particle (SEP) events is the detection of particles over a very extended range of longitudes in the heliosphere. This may be due to peculiarities of the magnetic field in the corona, to a broad accelerator, to cross-field transport of the particles, or to a combination of these processes. The eruptive …
HD 41641: A classical δ Sct-type pulsator with chemical signatures of an Ap star
Ryabchikova, T.; Poretti, E.; Michel, E. +8 more
Context. Among the known groups of pulsating stars, δ Sct stars are one of the least understood. Theoretical models do not predict the oscillation frequencies that observations reveal. Complete asteroseismic studies are necessary to improve these models and better understand the internal structure of these targets.
Aims: We study the δ Sct st…
Molecule survival in magnetized protostellar disk winds. II. Predicted H2O line profiles versus Herschel/HIFI observations
Ferreira, J.; Pineau des Forêts, G.; Cabrit, S. +1 more
Context. The origin of molecular protostellar jets and their role in extracting angular momentum from the accreting system are important open questions in star formation research. In the first paper of this series we showed that a dusty magneto-hydrodynamic (MHD) disk wind appeared promising to explain the pattern of H2 temperature and …
The TANAMI Multiwavelength Program: Dynamic spectral energy distributions of southern blazars
Buson, S.; Gehrels, N.; Dauser, T. +32 more
Context. Simultaneous broadband spectral and temporal studies of blazars are an important tool for investigating active galactic nuclei (AGN) jet physics.
Aims: We study the spectral evolution between quiescent and flaring periods of 22 radio-loud AGN through multiepoch, quasi-simultaneous broadband spectra. For many of these sources these ar…
Brown dwarf disks with Herschel: Linking far-infrared and (sub)-mm fluxes
Greaves, Jane; Testi, Leonardo; Jayawardhana, Ray +4 more
Brown dwarf disks are excellent laboratories to test our understanding of disk physics in an extreme parameter regime. In this paper we investigate a sample of 29 well-characterized brown dwarfs and very low-mass stars, for which Herschel far-infrared fluxes and (sub)-mm fluxes are available. We measured new Herschel/PACS fluxes for 11 objects and…
Extragalactic archeology with the GHOSTS Survey. I. Age-resolved disk structure of nearby low-mass galaxies
Bell, Eric F.; Holwerda, Benne W.; Monachesi, Antonela +5 more
Aims: We study the individual evolution histories of three nearby low-mass edge-on galaxies (IC 5052, NGC 4244, and NGC 5023).
Methods: Using resolved stellar populations, we constructed star count density maps for populations of different ages and analyzed the change of structural parameters with stellar age within each galaxy.
Res…
Observed and simulated power spectra of kinetic and magnetic energy retrieved with 2D inversions
Danilovic, S.; van Noort, M.; Rempel, M. +1 more
Context. Information on the origin of internetwork magnetic field is hidden at the smallest spatial scales.
Aims: We try to retrieve the power spectra with certainty to the highest spatial frequencies allowed by current instrumentation.
Methods: To accomplish this, we use a 2D inversion code that is able to recover information up to the …
The ionization rates of galactic nuclei and disks from Herschel/HIFI observations of water and its associated ions
van der Tak, F. F. S.; Güsten, R.; Weiß, A. +1 more
Context. Dense gas in galactic nuclei is known to feed central starbursts and AGN, but the properties of this gas are poorly known because of the high obscuration by dust.
Aims: Submm-wave spectroscopy of water and its associated ions is useful to trace the oxygen chemistry of interstellar gas, in particular to constrain its ionization rate. …
Wind mass transfer in S-type symbiotic binaries. II. Indication of wind focusing
Skopal, A.; Shagatova, N.; Cariková, Z.
Context. The wind mass transfer from a giant to its white dwarf companion in symbiotic binaries is not well understood. For example, the efficiency of wind mass transfer of the canonical Bondi-Hoyle accretion mechanism is too low to power the typical luminosities of the accretors. However, recent observations and modelling indicate a considerably …