Search Publications
Upward propagating high-frequency Alfvén waves as identified from dynamic wave-like spicules observed by SOT on Hinode
Tu, C. -Y.; Marsch, E.; Tian, H. +3 more
Aims: We identify high-frequency Alfvén waves propagating upward in the solar chromosphere and transition region from observation by Solar Optical Telescope (SOT) onboard Hinode.
Methods: The spicule shape is enhanced through application of a normal radial gradient filter and an un-sharp mask on the images taken by SOT. The displaced position …
Black hole growth and starburst activity at z = 0.6-4 in the Chandra Deep Field South. Host galaxies properties of obscured AGN
Merloni, A.; Fiore, F.; Comastri, A. +8 more
Aims: The co-evolution of host galaxies and the active black holes which reside in their centre is one of the most important topics in modern observational cosmology. Here we present a study of the properties of obscured active galactic nuclei (AGN) detected in the CDFS 1 Ms observation and their host galaxies.
Methods: We limited the analysis…
Comparison of transient horizontal magnetic fields in a plage region and in the quiet Sun
Ishikawa, R.; Tsuneta, S.
Aims: The properties of transient horizontal magnetic fields (THMFs) in both plage and quiet Sun regions are obtained and compared.
Methods: Spectro-polarimetric observations with the Solar Optical Telescope (SOT) on the Hinode satellite were carried out with a cadence of about 30 s for both plage and quiet regions located near the disk center…
Signatures of Alfvén waves in the polar coronal holes as seen by EIS/Hinode
Doyle, J. G.; Banerjee, D.; Pérez-Suárez, D.
Context: We diagnose the properties of the plume and interplume regions in a polar coronal hole and the role of waves in the acceleration of the solar wind.
Aims: We attempt to detect whether Alfvén waves are present in the polar coronal holes through variations in EUV line widths.
Methods: Using spectral observations performed over a pola…
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…