Search Publications

Analysis of power spectra of Doppler shift time series as a diagnostic tool for quiescent coronal loops
DOI: 10.1051/0004-6361:20066069 Bibcode: 2007A&A...462..331T

Doyle, J. G.; Erdélyi, R.; Bradshaw, S. J. +1 more

Context: Analysing the structure of solar coronal loops is crucial to our understanding of the processes which heat and maintain the coronal plasma at multimillion degree temperatures. The determination of the physical parameters of the loops remains both an observational and theoretical challenge.
Aims: The present work is aimed at tackling s…

2007 Astronomy and Astrophysics
SOHO 12
Birth and evolution of a dense coronal loop in a complex flare region
DOI: 10.1051/0004-6361:20065129 Bibcode: 2007A&A...466..339B

Fletcher, L.; Veronig, A.; Brown, J. C. +2 more

Context: During the 14th/15th of April 2002, several flares occurred in NOAA active region complex 9893/9910. Two of these were previously interpreted as having anomalously high coronal column densities.
Aims: We develop a scenario using multiwavelength observations to explain the high coronal column density (≈1020 cm-2) …

2007 Astronomy and Astrophysics
SOHO 12
Abundances in planetary nebulae: Hb 5
DOI: 10.1051/0004-6361:20066012 Bibcode: 2007A&A...462..179P

Pottasch, S. R.; Surendiranath, R.

The ISO spectra of the bilobal planetary nebula Hb 5 are presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebula is then calculated in several ways. First by directly calculating and adding individual ion a…

2007 Astronomy and Astrophysics
ISO 12
Compositional dependence of infrared absorption spectra of crystalline silicates. III. Melilite solid solution
DOI: 10.1051/0004-6361:20066009 Bibcode: 2007A&A...464..229C

Koike, C.; Tsuchiyama, A.; Chihara, H.

The infrared optical properties and absorption spectra of the melilite solid solution series are reported. Melilite is a high-temperature condensate, and is expected to condense during the early phase of the condensation sequence. In this study, samples of the melilite solid solution series were newly synthesized between the aluminium end member (…

2007 Astronomy and Astrophysics
ISO 12
Asteroseismology of exoplanets host stars: the special case of ι Horologii (HD 17051)
DOI: 10.1051/0004-6361:20066083 Bibcode: 2007A&A...463..657L

Vauclair, S.; Laymand, M.

Aims:This paper presents detailed analysis and modelisation of the star HD 17051 (alias ι Hor), which appears to be a specially interesting case among exoplanet host stars. Like most of these stars, ι Hor presents a metallicity excess that has been measured by various observers who give different results, ranging from [ Fe/H] = 0.11 to 0.26 and as…

2007 Astronomy and Astrophysics
Hipparcos 12
XMM-Newton view of the double-peaked Fe Kα complex in E1821+643
DOI: 10.1051/0004-6361:20065566 Bibcode: 2007A&A...461..917J

Guainazzi, M.; Santos-Lleó, M.; Jiménez-Bailón, E. +3 more

We present the results of the analysis of the hard band XMM-Newton spectra of the luminous, L2{-10 keV}∼3.4×1045 erg/s, radio-quiet quasar, E 1821+643. Two emission features were observed in the 6-7 keV rest frame band, confirming previous Chandra detection of these structures. We interpret these features as two single emissi…

2007 Astronomy and Astrophysics
XMM-Newton 11
Redshift-distance relations from type Ia supernova observations. New constraints on grey dust models
DOI: 10.1051/0004-6361:20065292 Bibcode: 2007A&A...464..465R

Cepa, J.; Robaina, A. R.

Extinction due to intergalactic grey dust has been proposed as an alternative to accelerated expansion to account for the dimming of SnIa fluxes beyond z ≃ 0.5. The "replenishing" grey dust model, although fitting the observational data, does not seem to be based on physical assumptions. For this reason, in this paper we propose a new grey dust mo…

2007 Astronomy and Astrophysics
eHST 11
The optical emission line spectrum of Mark 110
DOI: 10.1051/0004-6361:20078313 Bibcode: 2007A&A...475..487V

Kollatschny, W.; Véron-Cetty, M. -P.; Véron, P. +1 more

Aims:We analyse in detail the rich emission line spectrum of Mark 110 to determine the physical conditions in the nucleus of this object, a peculiar NLS1 without any detectable Fe II emission associated with the broad line region and with a λ5007/Hβ line ratio unusually large for a NLS1.
Methods: We use 24 spectra obtained with the Marcario Lo…

2007 Astronomy and Astrophysics
eHST 11
Thermal forces on planetary ring particles: application to the main system of Saturn
DOI: 10.1051/0004-6361:20067029 Bibcode: 2007A&A...471..717V

Vokrouhlický, D.; Nesvorný, D.; Dones, L. +1 more

Context: The motion of small particles in planetary rings is affected in the long-term by radiation forces. While the Poynting-Robertson effect has been extensively discussed and applied to the dynamics of micron-sized ring particles, studies of thermal self-acceleration of particles are only in their infancy.
Aims: We extend the pioneering wo…

2007 Astronomy and Astrophysics
Cassini 11
The distant galaxy cluster CL0016+16: X-ray analysis up to R{200}
DOI: 10.1051/0004-6361:20077966 Bibcode: 2007A&A...476...63S

Teyssier, R.; Solovyeva, L.; Anokhin, S. +2 more

Aims:CL0016+16 seems to be a good candidate for studying the mass distribution of galaxy clusters up to their Virial radius, since it is a bright massive cluster, previously considered as dynamically relaxed.
Methods: Using XMM-Newton observations of CL0016+16, we performed a careful X-ray background analysis and detected its X-ray emission co…

2007 Astronomy and Astrophysics
XMM-Newton 11