Search Publications
Outer edges of debris discs. How sharp is sharp?
Thébault, P.; Wu, Y.
Context: Rings or annulus-like features have been observed in most imaged debris discs. Outside the main ring, while some systems (e.g., β Pictoris and AU Mic) exhibit smooth surface brightness profiles (SB) that fall off roughly as ~r-3.5, others (e.g. HR 4796A and HD 139664) display large drops in luminosity at the ring's outer edge a…
Disks around CQ Tauri and MWC 758: dense PDR or gas dispersal?
Chapillon, E.; Guilloteau, S.; Dutrey, A. +1 more
Context: The overall properties of disks surrounding intermediate PMS stars (HAe) are not yet well constrained by current observations. The disk inclination, which significantly affects spectral energy distribution modeling, is often unknown.
Aims: We attempted to resolve the disks around CQ Tau and MWC 758 to provide accurate constraints on t…
Hinode XRT observations of a long-lasting coronal sigmoid
Canfield, R. C.; McKenzie, D. E.
Aims:Coronal sigmoids are important sources of eruptions into interplanetary space, and a handful of models have been proposed to explain their characteristic S shape. However, the coronal X-ray images available to date have generally not had sufficient resolution to distinguish between these models. The goal of the present investigation is to det…
Magnetic flux cancellation associated with a recurring solar jet observed with Hinode, RHESSI, and STEREO/EUVI
Young, P. R.; Mason, H. E.; Krucker, S. +7 more
Aims: We study the physical properties of a recurring solar active region jet observed in X-rays and extreme-ultraviolet (EUV).
Methods: Multi-wavelength data from all three instruments on board Hinode were analysed. X-ray imaging and spectroscopy of the microflaring emission associated with the jets was performed with the Reuven Ramaty High E…
The red clump absolute magnitude based on revised Hipparcos parallaxes
Groenewegen, M. A. T.
Context: Over the past decade the use of the red clump (RC) as distance indicator has increased in importance as this evolutionary phase is well populated and a good local calibration exists.
Aims: The absolute calibration of the RC in the I and K band is investigated again based on the recently published revised Hipparcos parallaxes.
Meth…
The multiple quasar Q2237+0305 under a microlensing caustic
Schmidt, R. W.; Anguita, T.; Wambsganss, J. +5 more
We use the high magnification event seen in the 1999 OGLE campaign light curve of image C of the quadruply imaged gravitational lens Q2237+0305 to study the structure of the quasar engine. We have obtained g'- and r'-band photometry at the Apache Point Observatory 3.5 m telescope where we find that the event has a smaller amplitude in the r'-band …
Density of neutral interstellar hydrogen at the termination shock from Ulysses pickup ion observations
Möbius, E.; Bzowski, M.; Gloeckler, G. +2 more
Aims: By reevaluating a 13-month stretch of Ulysses SWICS H pickup ion measurements near 5 AU close to the ecliptic right after the previous solar minimum, this paper presents a determination of the neutral interstellar H density at the solar wind termination shock and implications for the density and ionization degree of hydrogen in the local int…
High precision X-ray log N - log S distributions: implications for the obscured AGN population
Treister, E.; Ebrero, J.; Page, M. J. +13 more
Context: Our knowledge of the properties of AGN, especially those of optical type-2 objects, is very incomplete. Because extragalactic source count distributions are dependent on the cosmological and statistical properties of AGN, they provide a direct method of investigating the underlying source populations.
Aims: We aim to constrain the ext…
XMM-Newton observations of the supernova remnant IC 443. II. Evidence of stellar ejecta in the inner regions
Troja, E.; Miceli, M.; Bocchino, F. +1 more
Aims: We investigate the spatial distribution of the physical and chemical properties of the hot X-ray emitting plasma of the supernova remnant IC 443, to derive important constraints on its ionization stage, on the progenitor supernova explosion, on the age of the remnant, and its physical association with a close pulsar wind nebula.
Methods:…
XMM-Newton observations of the Lockman Hole: X-ray source catalogue and number counts
Cappelluti, N.; Barcons, X.; Fabian, A. C. +4 more
Context: The Lockman Hole field represents the sky area of lowest Galactic line-of-sight column density N_H=5.7 × 1019 cm-2. It was observed by the XMM-Newton X-ray observatory in 18 pointings for a total of 1.16 Ms (raw EPIC pn observing time) constituting the deepest XMM-Newton exposure so far. After the removal of time int…