Search Publications
A U-band survey of brown dwarfs in the Taurus molecular cloud with the XMM-Newton optical/UV monitor
Audard, M.; Güdel, M.; Grosso, N. +2 more
Aims:We aim to characterize the U-band variability of young brown dwarfs in the Taurus Molecular Cloud and discuss its origin.
Methods: We used the XMM-Newton Extended Survey of the Taurus Molecular Cloud, where a sample of 11 young bona fide brown dwarfs (spectral type later than M 6) were observed simultaneously in X-rays with XMM-Newton and…
The XMM-Newton survey in the Marano field. I. The X-ray data and optical follow-up
Hasinger, G.; Mignoli, M.; Zamorani, G. +6 more
We report on a medium deep XMM-Newton survey of the Marano Field and optical follow-up observations. The mosaicked XMM-Newton pointings in this optical quasar survey field cover 0.6 deg2 with a total of 120 ks good observation time. We detected 328 X-ray sources in total. The turnover flux of our sample is fX∼ 5 × 10-15<…
Analysis of power spectra of Doppler shift time series as a diagnostic tool for quiescent coronal loops
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…
Birth and evolution of a dense coronal loop in a complex flare region
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) …
Abundances in planetary nebulae: Hb 5
Pottasch, S. R.; Surendiranath, R.
The ISO spectra of the bilobal planetary nebula
Compositional dependence of infrared absorption spectra of crystalline silicates. III. Melilite solid solution
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 (…
Asteroseismology of exoplanets host stars: the special case of ι Horologii (HD 17051)
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…
XMM-Newton view of the double-peaked Fe Kα complex in E1821+643
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…
Redshift-distance relations from type Ia supernova observations. New constraints on grey dust models
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…
The optical emission line spectrum of Mark 110
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…