Search Publications
Atmospheric parameters and carbon abundance for hot DB white dwarfs
Gänsicke, B. T.; Koester, D.; Provencal, J.
Atmospheric parameters for hot DB (helium atmosphere) white dwarfs near effective temperatures of 25 000 K are extremely difficult to determine from optical spectroscopy. The neutral He lines reach a maximum in this range and change very little with effective temperature and surface gravity. Moreover, an often unknown amount of hydrogen contaminat…
A quiescent galaxy at the position of the long GRB 050219A
Covino, S.; Pian, E.; D'Elia, V. +25 more
Context. Long-duration gamma-ray bursts (LGRBs) are produced by the collapse of very massive stars. Because of the short life time of their progenitors, LGRBs pinpoint star-forming galaxies. Recent studies demonstrate that LGRBs populate all types of star-forming galaxies from sub-luminous, blue compact dwarfs to luminous infrared galaxies.
A…
Wind collisions in three massive stars of Cygnus OB2
Nazé, Yaël; Rauw, Gregor; Cazorla, Constantin
Aims: We wish to study the origin of the X-ray emission of three massive stars in the Cyg OB2 association: Cyg OB2 #5, Cyg OB2 #8A, and Cyg OB2 #12.
Methods: To this aim, dedicated X-ray observations from XMM-Newton and Swift are used, as well as archival ROSAT and Suzaku data.
Results: Our results on Cyg OB2 #8A improve the phase c…
A non-equilibrium ortho-to-para ratio of water in the Orion PDR
Bergin, E. A.; Plume, R.; van der Tak, F. F. S. +1 more
Context. The ortho-to-para ratio (OPR) of H2O is thought to be sensitive to the temperature of water formation. The OPR of H2O is thus useful for studying the formation mechanism of water.
Aims: We investigate the OPR of water in the Orion PDR (photon-dominated region), at the Orion Bar and Orion S positions, using data …
Deep optical observations of the γ-ray pulsar J0357+3205
Zharikov, S.; Shternin, P.; Kirichenko, A. +3 more
Context. A middle-aged radio-quiet pulsar J0357+3205 was discovered in gamma rays with Fermi and later in X-rays with Chandra and XMM-Newton observatories. It produces an unusual thermally emitting pulsar wind nebula that is observed in X-rays.
Aims: Deep optical observations were obtained to search for the pulsar optical counterpart and its …
Planetary companions in K giants β Cancri, µ Leonis, and β Ursae Minoris
Hatzes, A. P.; Lee, B. -C.; Park, M. -G. +3 more
Aims: The aim of our paper is to investigate the low-amplitude and long-period variations in evolved stars with a precise radial velocity survey.
Methods: The high-resolution, the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) was used from 2003 to 2013 for a radial velocity survey of giant stars as part of the exoplanet sea…
The scale height of gas traced by [C ii] in the Galactic plane
Langer, W. D.; Pineda, J. L.; Velusamy, T.
Context. The distribution of various interstellar gas components and the pressure in the interstellar medium (ISM) is a result of the interplay of different dynamical mechanisms and energy sources on the gas in the Milky Way. The scale heights of the different gas tracers, such as H i and CO, are a measure of these processes. The scale height of […
Characteristics of polar coronal hole jets
Teriaca, L.; Gupta, G. R.; Bemporad, A. +2 more
Context. High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind.
Aims: We studied the dynamics of two jets seen in a polar coronal hole with a…
Dynamical star-disk interaction in the young stellar system V354 Monocerotis
Bouvier, J.; Favata, F.; Alencar, S. H. P. +2 more
Aims: The main goal of this work is to characterize the mass accretion and ejection processes of the classical T Tauri star
Methods: In March 2008, photometric and spectroscopic observations of
Water distribution in shocked regions of the NGC 1333-IRAS 4A protostellar outflow
Liseau, R.; Codella, C.; van Dishoeck, E. F. +11 more
Context. Water is a key molecule in protostellar environments because its line emission is very sensitive to both the chemistry and the physical conditions of the gas. Observations of H2O line emission from low-mass protostars and their associated outflows performed with HIFI onboard the Herschel Space Observatory have highlighted the c…