Search Publications
Evolution of sunspot properties during solar cycle 23
Fletcher, L.; Marshall, S.; Watson, F. T.
Context. The long term study of the Sun is necessary if we are to determine the evolution of sunspot properties and thereby inform modeling of the solar dynamo, particularly on scales of a solar cycle.
Aims: We aim to determine a number of sunspot properties over cycle 23 using the uniform database provided by the SOHO Michelson Doppler Image…
HST/STIS Lyman-α observations of the quiet M dwarf GJ 436 . Predictions for the exospheric transit signature of the hot Neptune GJ 436b
Ehrenreich, D.; Delfosse, X.; Lecavelier Des Etangs, A.
Lyman-α (Lyα) emission of neutral hydrogen (λ1215.67 Å) is the main contributor to the ultraviolet flux of low-mass stars such as M dwarfs. It is also the main light source used in studies of the evaporating upper atmospheres of transiting extrasolar planets with ultraviolet transmission spectroscopy. However, there are very few observations of th…
Multiwavelength campaign on Mrk 509. II. Analysis of high-quality Reflection Grating Spectrometer spectra
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +11 more
Aims: We study the bright Seyfert 1 galaxy Mrk 509 with the Reflection Grating Spectrometers (RGS) of XMM-Newton, using for the first time the RGS multi-pointing mode of XMM-Newton to constrain the properties of the outflow in this object. We obtain very accurate spectral properties from a 600 ks spectrogram of Mrk 509 with excellent quality.…
Abundances of the elements He to Ni in the atmosphere of Sirius A
Landstreet, J. D.
Context. The abundances of elements in the atmosphere of an individual star provide a very broad range of extremely important information about the formation and evolution history of that star. Specifically, during the main sequence phase, the abundance pattern observed can provide valuable constraints on a range of hydrodynamical processes occurr…
The diameter of the CoRoT target HD 49933. Combining the 3D limb darkening, asteroseismology, and interferometry
Morel, P.; Berio, P.; Kervella, P. +21 more
Context. The interpretation of stellar pulsations in terms of internal structure depends on the knowledge of the fundamental stellar parameters. Long-base interferometers permit us to determine very accurate stellar radii, which are independent constraints for stellar models that help us to locate the star in the HR diagram.
Aims: Using a dir…
The Herschel M 33 extended survey (HerM33es): PACS spectroscopy of the star-forming region BCLMP 302
Boquien, M.; Braine, J.; Calzetti, D. +19 more
Context. The emission line of [C ii] at 158 µm is one of the strongest cooling lines of the interstellar medium (ISM) in galaxies.
Aims: Distinguishing the relative contributions of the different ISM phases to [C ii] emission is a major objective of the HerM33es program, a Herschel key project to study the ISM in the nearby spiral galax…
XMM-Newton observations of the low-mass X-ray binary EXO 0748-676 in quiescence
Díaz Trigo, M.; Boirin, L.; Costantini, E. +2 more
The neutron star low-mass X-ray binary EXO 0748-676 started a transition from outburst to quiescence in August 2008, after more than 24 years of continuous accretion. The return of the source to quiescence has been monitored extensively by several X-ray observatories. Here, we report on four XMM-Newton observations elapsing a period of more than 1…
Discovery of the source HESS J1356-645 associated with the young and energetic PSR J1357-6429
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +195 more
Context. Several newly discovered very-high-energy (VHE; E > 100 GeV) γ-ray sources in the Galaxy are thought to be associated with energetic pulsars. Among them, middle-aged (≳ 104 yr) systems exhibit large centre-filled VHE nebulae, offset from the pulsar position, which result from the complex relationship between the pulsar wind …
Molecular Gas in NUclei of GAlaxies (NUGA). XIV. The barred LINER/Seyfert 2 galaxy NGC 3627
Hunt, L. K.; Combes, F.; García-Burillo, S. +2 more
We present 12CO(1-0) and 12CO(2-1) maps of the interacting barred LINER/Seyfert 2 galaxy NGC 3627 obtained with the IRAM interferometer at resolutions of 2.1 arcsec × 1.3 arcsec and 0.9 arcsec × 0.6 arcsec, respectively. We also present single-dish IRAM 30 m 12CO(1-0) and 12CO(2-1) observations used to c…
The quiet Sun average Doppler shift of coronal lines up to 2 MK
Solanki, S. K.; Teriaca, L.; Dadashi, N.
Context. The average Doppler shift shown by spectral lines formed from the chromosphere to the corona reveals important information on the mass and energy balance of the solar atmosphere, providing an important observational constraint to any models of the solar corona. Previous spectroscopic observations of vacuum ultra-violet (VUV) lines have re…