Search Publications
Short-lived spots in solar-like stars as observed by CoRoT
Auvergne, M.; Baudin, F.; Baglin, A. +4 more
Context: CoRoT light curves have an unprecedented photometric quality, having simultaneously a high signal-to-noise ratio, a long time span and a nearly continuous duty-cycle.
Aims: We analyse the light-curves of four bright targets observed in the seismology field and study short-lived small spots in solar-like stars.
Methods: We present …
Searching for a link between the magnetic nature and other observed properties of Herbig Ae/Be stars and stars with debris disks
Hamaguchi, K.; Hubrig, S.; Stelzer, B. +6 more
Context: Recently, evidence for the presence of weak magnetic fields in Herbig Ae/Be stars has been found in several studies.
Aims: We seek to expand the sample of intermediate-mass pre-main sequence stars with circular polarization data to measure their magnetic fields, and to determine whether magnetic field properties in these stars are cor…
A multi-periodic oscillatory event in a solar flare
Nakariakov, V. M.; Inglis, A. R.
Aims: Ratios of different significant periods found in the light curves of a solar flare exhibiting quasi-periodic pulsations (QPP) are used to distinguish between the possible physical mechanisms responsible for such periodic behaviour.
Methods: Time series data of the flaring event of 2002 July 3, observed via the Nobeyama Radioheliograph, N…
XMM-Newton detects a relativistically broadened iron line in the spectrum of the ms X-ray pulsar SAX J1808.4-3658
Robba, N. R.; Papitto, A.; Di Salvo, T. +5 more
We report on a 63-ks long XMM-Newton observation of the accreting millisecond pulsar SAX J1808.4-3658 during the latest X-ray outburst which started on September 21st 2008. The pn spectrum shows a highly significant emission line in the energy band where the iron K-α line is expected, and which we identify as emission from neutral (or mildly ioniz…
Solar-like oscillations in HD 181420: data analysis of 156 days of CoRoT data
Auvergne, M.; Baudin, F.; García, R. A. +18 more
Context: The estimate of solar-like oscillation properties, such as their frequencies, amplitudes and lifetimes, is challenging because of their low amplitudes and will benefit from long and uninterrupted observing runs. The space telescope CoRoT allows us to obtain high-performance photometric data over a long and quasi continuous period. Among i…
A ~4.6 h quasi-periodic oscillation in the BL Lacertae PKS 2155-304?
Gupta, A. C.; Lachowicz, P.; Gaur, H. +1 more
We report a possible detection of an ~4.6-h quasi-periodic oscillation (QPO) in the 0.3-10 keV emission of the high-energy peaked blazar PKS 2155-304 from a 64 ks observation by the XMM-Newton EPIC/pn detector. We identify a total modulation of ~5% in the light curve and confirm that nominal period by periodogram, structure function, and wavelet a…
CoRoT's view of newly discovered B-star pulsators: results for 358 candidate B pulsators from the initial run's exoplanet field data
Auvergne, M.; Deleuil, M.; Jorda, L. +18 more
Context: We search for new variable B-type pulsators in the CoRoT data assembled primarily for planet detection, as part of CoRoT's additional programme.
Aims: We aim to explore the properties of newly discovered B-type pulsators from the uninterrupted CoRoT space-based photometry and to compare them with known members of the β Cep and slowly …
The interstellar Ca II distance scale
Krełowski, J.; Galazutdinov, G. A.; Strobel, A. +1 more
Aims: We attempt to extend the relation between the strengths of the interstellar Ca II lines and the distances to early-type stars to objects beyond 1 kiloparsec, with the line saturation taken into account.
Methods: We measure the Ca II K and Ca II H equivalent widths, and compute Ca II column densities for 262 lines of sight towards early-t…
The onset of solar cycle 24. What global acoustic modes are telling us
Jiménez-Reyes, S. J.; García, R. A.; Pallé, P. L. +1 more
We study the response of the low-degree, solar p-mode frequencies to the unusually extended minimum of solar surface activity since 2007. A total of 4768 days of observations collected by the space-based, Sun-as-a-star helioseismic GOLF instrument are analyzed. A multi-step iterative maximum-likelihood fitting method is applied to subseries of 365…
Evolution of red-sequence cluster galaxies from redshift 0.8 to 0.4: ages, metallicities, and morphologies
Moustakas, J.; Pelló, R.; White, S. D. M. +14 more
We present a comprehensive analysis of the stellar population properties and morphologies of red-sequence galaxies in 24 clusters and groups from z∼0.75 to z∼0.45. The dataset, consisting of 215 spectra drawn from the ESO Distant Cluster Survey, constitutes the largest spectroscopic sample at these redshifts for which such an analysis has been con…