Search Publications
First spectro-interferometric survey of Be stars. I. Observations and constraints on the disk geometry and kinematics
Hofmann, K. -H.; Meilland, A.; Millour, F. +5 more
Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed infrared-excess and emission lines. The phenomena involved in the disk formation still remain highly debated.
Aims: To progress in the understanding of the physical process or processes responsible for the m…
The VLT-FLAMES Tarantula Survey. VII. A low velocity dispersion for the young massive cluster R136
van Loon, J. Th.; Crowther, P. A.; Bastian, N. +8 more
Detailed studies of resolved young massive star clusters are necessary to determine their dynamical state and evaluate the importance of gas expulsion and early cluster evolution. In an effort to gain insight into the dynamical state of the young massive cluster R136 and obtain the first measurement of its velocity dispersion, we analyse multi-epo…
Coronal hole boundaries at small scales. IV. SOT view. Magnetic field properties of small-scale transient brightenings in coronal holes
Doyle, J. G.; Madjarska, M. S.; Huang, Z. +1 more
Context. We study the magnetic properties of small-scale transients in coronal holes and a few in the quiet Sun identified in X-ray observations and spectroscopic data in two previous papers.
Aims: We aim to investigate the role of small-scale transients in the evolution of the magnetic field in an equatorial coronal hole.
Methods: Two s…
Outburst of GX 304-1 monitored with INTEGRAL: positive correlation between the cyclotron line energy and flux
Klochkov, D.; Santangelo, A.; Wilms, J. +10 more
Context. X-ray spectra of many accreting pulsars exhibit significant variations as a function of flux and thus of mass accretion rate. In some of these pulsars, the centroid energy of the cyclotron line(s), which characterizes the magnetic field strength at the site of the X-ray emission, has been found to vary systematically with flux.
Aims:…
The complete far-infrared and submillimeter spectrum of the Class 0 protostar Serpens SMM1 obtained with Herschel. Characterizing UV-irradiated shocks heating and chemistry
van Dishoeck, E. F.; Cernicharo, J.; Goicoechea, J. R. +8 more
We present the first complete ~55-671 µm spectral scan of a low-mass Class 0 protostar (Serpens SMM1) taken with the PACS and SPIRE spectrometers onboard Herschel. More than 145 lines have been detected, most of them rotationally excited lines of 12CO (full ladder from Ju = 4-3 to 42-41 and Eu/k = 4971 K), H<…
Luminosity and mass functions of the three main sequences of the globular cluster NGC 2808
Anderson, J.; Milone, A. P.; Marino, A. F. +5 more
High-precision HST photometry has revealed that the globular cluster (GC) NGC 2808 hosts a triple main sequence (MS) corresponding to three stellar populations with different helium abundances. We carried out photometry on ACS/WFC HST images of NGC 2808 with the main purpose of measuring the luminosity function (LF) of stars in the three different…
Evolution of dust in the Orion Bar with Herschel. I. Radiative transfer modelling
Abergel, A.; Martin, P. G.; White, G. J. +5 more
Context. Interstellar dust is a key element in our understanding of the interstellar medium and star formation. The manner in which dust populations evolve with the excitation and the physical conditions is a first step in comprehending the evolution of interstellar dust.
Aims: Within the framework of the Evolution of interstellar dust Hersch…
Gas modelling in the disc of HD 163296
Pinte, C.; Ménard, F.; Duchêne, G. +19 more
We present detailed model fits to observations of the disc around the Herbig Ae star HD 163296. This well-studied object has an age of ~4 Myr, with evidence of a circumstellar disc extending out to ~540 AU. We use the radiation thermo-chemical disc code ProDiMo to model the gas and dust in the circumstellar disc of HD 163296, and attempt to determ…
The VLT-FLAMES Tarantula Survey. IV. Candidates for isolated high-mass star formation in 30 Doradus
Crowther, P. A.; Bastian, N.; de Koter, A. +15 more
Whether massive stars (≳30 M⊙) can occasionally form in relative isolation (e.g. in clusters with M < 100 M⊙) or if they require a large cluster of lower-mass stars around them is a key test in the differentiation of star-formation theories as well as how the initial mass function of stars is sampled. Previous attempts to …
Nitrogen line spectroscopy in O-stars. III. The earliest O-stars
Puls, J.; Najarro, F.; Massey, P. +1 more
Context. The classification scheme proposed by Walborn et al. (2002, AJ, 123, 2754), based primarily on the relative strengths of the N ivλ4058 and N iiiλ4640 emission lines, has been used in a variety of studies to spectroscopically classify early O-type stars. Owing to the lack of a solid theoretical basis, this scheme has not yet been universal…