Search Publications
Projection of circumstellar disks on their environments
Pontoppidan, K. M.; Dullemond, C. P.
We use a 3D Monte Carlo radiative transfer code to study the projection of large shadows by circumstellar disks around young stellar objects on surrounding reflection nebulosity. It is shown that for a wide range of parameters a small (10-100 AU) circumstellar disk can project a large (1000-10 000 AU) dark band in the near-infrared that often rese…
Phosphorus in the diffuse interstellar medium
Lebouteiller, V.; Ferlet, R.; Kuassivi
We present FUSE and HST/STIS measurements of the P ii column density toward Galactic stars. We analyzed P ii through the profile fitting of the unsaturated λ1125 and λ1533 lines and derived column densities integrated along the sightlines as well as in individual resolved components. We find that phosphorus is not depleted along those sightlines s…
Massive elliptical galaxies in X-rays: The role of late gas accretion
Matteucci, F.; Kawata, D.; Gibson, B. K. +1 more
We present a new chemical evolution model meant to be a first step in the self-consistent study of both optical and X-ray properties of elliptical galaxies. Detailed cooling and heating processes in the interstellar medium (ISM) are taken into account using a mono-phase one-zone treatment which allows a more reliable modelling of the galactic wind…
X-rays from α Centauri - The darkening of the solar twin
Schmitt, J. H. M. M.; Robrade, J.; Favata, F.
We present first results from five XMM-Newton observations of the binary system α Centauri, which has been observed in snapshot like exposures of roughly two hours each during the last two years. In all our observations the X-ray emission of the system is dominated by α Cen B, a K1 star. The derived light curves of the individual components reveal…
On the widths and ratios of Mg X 609.79 and 624.94 Å lines in polar off-limb regions
Doyle, J. G.; Banerjee, D.; O'Shea, E.
Using measurements of Mg X 609.78 and 624.94 Å lines from the Coronal Diagnostic Spectrometer (CDS) on board SOHO, we seek to examine the variation of line width and line ratio in regions far off-limb at the Northern pole of the Sun. It is found that above ≈1150´´ the ratio of the two coronal Mg X resonance lines reduces to values that might be ex…
Time scales of the slowly drifting pulsating structure observed during the April 12, 2001 flare
Bárta, M.; Karlický, M.; Mészárosová, H. +1 more
First time scales of high-frequency (500-1500 MHz) slowly drifting pulsating structures observed during the April 12, 2001 flare by the Ondřejov (800-4500 MHz) and Potsdam (40-800 MHz) radiospectrographs and by the 1420 and 610 MHz Trieste radiopolarimeters (with high time resolution (1 ms)) are studied statistically. The Fourier method reveals pe…
SN 2002kg - the brightening of LBV V37 in NGC 2403
Weis, K.; Bomans, D. J.
SN 2002kg is a type IIn supernova, detected in October 2002 in the nearby spiral galaxy NGC 2403. We show that the position of SN 2002kg agrees within the errors with the position of the LBV V37. Ground based and HST ACS images however show that V37 is still present after the SN 2002kg event. We compiled a lightcurve of V37 which underlines the va…
Prominence atlas in the SUMER range 800-1250 Å. II. Line profile properties and ions identifications
Vial, J. -C.; Parenti, S.; Lemaire, P.
We present a SOHO/SUMER spectral atlas in the 800-1250 Å range of a prominence and a Quiet Sun (QS) region observed in 1999. The atlas is produced for two separate areas of the prominence. The QS spectrum is used as a reference. This is the first prominence atlas obtained with high spectral resolution (≈0.044 Å). It provides information concerning…
Dynamics of solar active regions. II. Oscillations observed with MDI and their relation to the magnetic field topology
Muglach, K.; Staude, J.; Hofmann, A.
We present new results of an international joint observing campaign, which was carried out in September 2000 to study the oscillatory behaviour of solar active regions. We concentrate on oscillations in the lower layers of the solar atmosphere as observed with the Michelson Doppler Imager (MDI, Scherrer et al. 1995, Sol. Phys., 162, 129). The resu…
An XMM-Newton observation of A3921: An off-axis merger
Pratt, G. W.; Bourdin, H.; Sauvageot, J. -L. +1 more
We present the results of a detailed analysis of the XMM-Newton observation of the galaxy cluster Abell 3921. The X-ray morphology of the cluster is elliptical, with the centroid offset from the brightest cluster galaxy by 17 arcsec, and with a pronounced extension toward the NW. Subtraction of a 2D β-model fit to the main cluster emission reveals…