Search Publications
A bright coronal downflow seen in multi-wavelength observations: evidence of a bifurcating flux-rope?
Solanki, S. K.; Mason, H. E.; Webb, D. F. +1 more
Aims:We study the origin and characteristics of a bright coronal downflow seen after a coronal mass ejection associated with erupting prominences on 5 March 2000.
Methods: This study extends that of Tripathi et al. (2006b, A&A, 449, 369) based on the Extreme-ultraviolet Imaging Telescope (EIT), the Soft X-ray Telescope (SXT) and the Large …
NGC 2298: a globular cluster on its way to disruption
Pulone, L.; de Marchi, G.
We have studied the stellar main sequence (MS) of the globular cluster NGC 2298 using deep HST/ACS observations in the F606W and F814W bands covering an area of 3.4 arcmin × 3.4 arcmin around the cluster centre or about twice the cluster's half-mass radius. The colour-magnitude diagram that we derive in this way reveals a narrow and well defined M…
Oxygen temperature anisotropy and solar wind heating above coronal holes out to 5 R⊙
Antonucci, E.; Telloni, D.; Dodero, M. A.
The purpose of the paper is to measure the degree of temperature anisotropy of the oxygen ions in the outer corona. The ratio of the Doppler dimmed O VI 1037-1032 line intensity as a function of the velocity of the fast solar wind, computed for typical values of coronal density, is consistent with the observed ratio, only when a significant temper…
Flare magnetic reconnection and relativistic particles in the 2003 October 28 event
Vial, J. -C.; Li, C.; Dai, Y. +2 more
An X17.2 solar flare occurred on 2003 October 28, accompanied by multi-wavelength emissions and a high flux of relativistic particles observed at 1 AU. We present the analytic results of the TRACE, SOHO, RHESSI, ACE, GOES, hard X-ray (INTEGRAL satellite), radio (Ondeřejov radio telescope), and neutron monitor data. It is found that the inferred ma…
Plasma condensation in coronal loops
Doyle, J. G.; Banerjee, D.; O'Shea, E.
Aims:Using temporal series data from the Coronal Diagnostic Spectrometer (CDS) on SOHO, we seek to investigate plasma condensation through the use of spectroscopic analysis.
Methods: Using a space-time (X-T) type plot we show, for a number of transition region (TR) and coronal lines, the variation of intensity (radiant flux) with time in an of…
A deconvolution-based algorithm for crowded field photometry with unknown point spread function
Magain, P.; Gillon, M.; Courbin, F. +4 more
A new method is presented for determining the point
spread function (PSF) of images that lack bright and isolated stars. It is based on the same principles as the MCS image deconvolution algorithm. It uses the information contained in all stellar images to achieve the double task of reconstructing the PSFs for single or mu…The XMM-Newton view of IRAS 09104+4109: evidence for a changing-look Type 2 quasar?
Fiore, F.; Piconcelli, E.; Comastri, A. +4 more
Aims:We report on a 14 ks XMM-Newton observation of the hyperluminous infrared galaxy IRAS 09104+4109, which harbors a type 2 quasar in its nucleus. Our analysis was aimed at studying the properties of the absorbing matter and the Fe K complex at 6-7 keV in this source.
Methods: We analyzed the spectroscopic data from the PN and the MOS camera…
Simultaneous INTEGRAL and RXTE observations of the accreting millisecond pulsar HETE J1900.1-2455
Stella, L.; Bonnet-Bidaud, J. M.; Kuiper, L. +5 more
Aims:HETE J1900.1-2455 is the seventh known X-ray transient accreting millisecond pulsar and has been in outburst for more than one year. We compared the data on HETE J1900.1-2455 with other similar objects and made an attempt at deriving constraints on the physical processes responsible for a spectral formation.
Methods: The broad-band spectr…
Observational signatures of the interaction between acoustic waves and the solar magnetic canopy
McIntosh, S. W.; Jefferies, S. M.; Armstrong, J. D. +1 more
Aims:We show that the spatial distribution (and its variation with frequency) of the power spectra of the velocity and intensity signals, in and around solar active regions, is a manifestation of the interaction of acoustic waves at the magnetic canopy.
Methods: We analysed 6 h of simultaneous, full-disk, velocity and intensity images obtained…
A refined analysis of the remarkable Bp star HR 6000
Hubrig, S.; Castelli, F.
Aims:UVES spectra of the very young (∼ 107 years) peculiar B-type star HR 6000 were analyzed in the near-UV and visual spectral regions (3050-9460 Å) with the aim of extending to other spectral ranges the study made previously in the UV using IUE spectra.
Methods: Stellar parameters T_eff = 12 850 K, log g = 4.10, and ξ=0 km s-…