Search Publications
NLTE carbon abundance determination in selected A- and B-type stars and the interpretation of C I emission lines
Mashonkina, L. I.; Alexeeva, S. A.; Ryabchikova, T. A.
We constructed a comprehensive model atom for C I-C II using the most up-to-date atomic data available and evaluated the non-local thermodynamic equilibrium (NLTE) line formation for C I and C II in classical 1D models representing the atmospheres of A- and late B-type stars. Our NLTE calculations predict the emission that appears at effective tem…
X-Ray Observations of Bow Shocks around Runaway O Stars. The Case of ζ Oph and BD+43°3654
Pohl, M.; Guerrero, M. A.; Toalá, J. A. +3 more
Non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. We present X-ray observations toward the runaway stars ζ Oph by Chandra and Suzaku and of BD+43°3654 by XMM-Newton to search for the presence of non-thermal X-ray emission. We found no evidence of non-thermal emission spatially coincident w…
Slipping Magnetic Reconnection of Flux-rope Structures as a Precursor to an Eruptive X-class Solar Flare
Hou, Yijun; Li, Ting; Zhang, Jun +1 more
We present the quasi-periodic slipping motion of flux-rope structures prior to the onset of an eruptive X-class flare on 2015 March 11, obtained by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The slipping motion occurred at the north part of the flux rope and seemed to successively peel off the flux rope. The spee…
Atomic-to-molecular gas phase transition triggered by the radio jet in Centaurus A
Combes, F.; Salomé, P.; Salomé, Q. +1 more
NGC 5128 (Centaurus A) is one of the best example to study AGN-feedback in the local Universe. At 13.5 kpc from the galaxy, optical filaments with recent star formation are lying along the radio-jet direction. We used the Atacama Pathfinder EXperiment (APEX) to map the CO(2-1) emission all along the filaments structure. Molecular gas mass of (8.2 …
Continued decay in the cyclotron line energy in Hercules X-1
Harrison, F. A.; Klochkov, D.; Wilms, J. +2 more
The centroid energy Ecyc of the cyclotron line in the spectrum of the binary X-ray pulsar
Characterizing the Youngest Herschel-detected Protostars. II. Molecular Outflows from the Millimeter and the Far-infrared
Manoj, P.; Wyrowski, Friedrich; Fischer, William J. +7 more
We present Combined Array for Research in Millimeter-wave Astronomy (CARMA) CO (J=1\to 0) observations and Herschel PACS spectroscopy, characterizing the outflow properties toward extremely young and deeply embedded protostars in the Orion molecular clouds. The sample comprises a subset of the Orion protostars known as the PACS Bright Red Sources …
Radio Diagnostics of Electron Acceleration Sites During the Eruption of a Flux Rope in the Solar Corona
Gallagher, Peter T.; Carley, Eoin P.; Vilmer, Nicole
Electron acceleration in the solar corona is often associated with flares and the eruption of twisted magnetic structures known as flux ropes. However, the locations and mechanisms of such particle acceleration during the flare and eruption are still subject to much investigation. Observing the exact sites of particle acceleration can help confirm…
Abnormal oscillation modes in a waning light bridge
Walsh, Robert W.; Yuan, Ding
Context. A sunspot acts as a waveguide in response to the dynamics of the solar interior; the trapped waves and oscillations could reveal its thermal and magnetic structures.
Aims: We study the oscillations in a sunspot intruded by a light bridge, and the details of these oscillations could reveal the fine structure of the magnetic topology. …
A recent change in the optical and γ-ray polarization of the Crab nebula and pulsar
Hallinan, G.; Laurent, P.; Moran, P. +4 more
We report on observations of the polarization of optical and γ-ray photons from the Crab nebula and pulsar system using the Galway Astronomical Stokes Polarimeter (GASP), the Hubble Space Telescope, Advanced Camera for Surveys and the International Gamma-Ray Astrophysics Laboratory satellite (INTEGRAL). These, when combined with other optical pola…
The ALMA detection of CO rotational line emission in AGB stars in the Large Magellanic Cloud
van Loon, J. Th.; Olofsson, H.; Sahai, R. +21 more
Context. Low- and intermediate-mass stars lose most of their stellar mass at the end of their lives on the asymptotic giant branch (AGB). Determining gas and dust mass-loss rates (MLRs) is important in quantifying the contribution of evolved stars to the enrichment of the interstellar medium.
Aims: This study attempts to spectrally resolve CO…