Search Publications
Effervescent heating: constraints from nearby cooling flow clusters observed with XMM-Newton
Kaastra, J. S.; Piffaretti, R.
Aims.We have used deprojected radial density and temperature profiles of a sample of 16 nearby CF clusters observed with XMM-Newton to test whether the effervescent heating model can satisfactorily explain the dynamics of CF clusters.
Methods.For each cluster we derived the required extra heating as a function of cluster-centric distance for va…
XMM-Newton discovery of the X-ray transient XMMU J181227.8-181234 in the Galactic plane
Cackett, Edward M.; Wijnands, Rudy; Remillard, Ron
We report the discovery of an X-ray transient, observed in outburst with XMM-Newton on 2003 March 20, and with position (J2000, approximate positional error 2arcsec). No known source is present at this position and the source was not detected during published ROSAT or ASCA observations of that region. However, the source may be associated with 1H1…
The Concept of a Stare-Mode Astrometric Space Mission
Zacharias, N.; Dorland, B.
In this paper, we introduce the concept of a stare-mode astrometric space mission. The traditionally accepted mode of operation for a mapping astrometric space mission is that of a continuously scanning satellite, such as the successful Hipparcos and planned Gaia missions. With the advent of astrometry missions mapping out stars to 20th magnitude,…
The NICMOS Polarimetric Calibration
Axon, D.; Batcheldor, D.; Sparks, W. +3 more
An accurate knowledge of the absolute calibration of the polarizing elements in the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) becomes especially important when conducting studies that require measuring degrees of polarization of close to 1% in the near-infrared. We present a comprehensive study of all previously observed polarime…
Estimating the Thickness of the Heliosheath from CELIAS/HSTOF and Voyager 1 Data
Hsieh, K. C.; Hilchenbach, M.; Czechowski, A. +2 more
We use recent Voyager 1 measurements of the ion fluxes beyond the termination shock and the SOHO HSTOF/CELIAS measured fluxes of the energetic neutral hydrogen and helium at 1 AU to estimate the neutral hydrogen column density NH in the heliosheath. Our best estimate is NH=1.13×1014 cm-2. The result corr…
The infrared void in the Lupus dark clouds revisited: a polarimetric approach
Franco, G. A. P.; Alves, F. O.
The results of B-band CCD imaging linear polarimetry obtained for stars from the Hipparcos catalogue are used to re-examine the distribution of the local interstellar medium towards the IRAS 100-µm emission void in the Lupus dark clouds. The analysis of the obtained parallax-polarization diagram assigns to the dark cloud Lupus1 a distance be…
New multi-fluid MHD model of comet 26P/Grigg-Skjellerup: Extrapolation to comet 67P/Churyumov-Gerasimenko
Benna, M.; Mahaffy, P. R.
The Multi-fluid MHD simulator CASIM3D models the atmosphere of comet 26P/Grigg-Skjellerup as it was seen by the Giotto spacecraft during its flyby of the comet in July 1992. CASIM3D integrates the major chemical reactions and physical interactions to compute self-consistently over an adaptive Cartesian mesh the dynamics of ions, electrons, and neu…
Subarcsecond Resolution Mid-Infrared Observations of Super Star Clusters in the Antennae (NGC 4038/4039)
Schaerer, D.; Wang, Z.; Brandl, B. R. +3 more
We present ground-based subarcsecond mid-infrared imaging and spectroscopy of young super star clusters in the overlap region of the merging galaxies NGC 4038/4039 (the Antennae) obtained with the VLT Imager and Spectrometer for mid-InfraRed (VISIR). With its unprecedented spatial resolution, VISIR begins for the first time to resolve the H II/pho…
Titan imagery with Keck adaptive optics during and after probe entry
de Pater, Imke; Brown, Michael E.; Marchis, Franck +6 more
We present adaptive optics data from the Keck telescope, taken while the Huygens probe descended through Titan's atmosphere and on the days following touchdown. No probe entry signal was detected. Our observations span a solar phase angle range from 0.05° up to 0.8°, with the Sun in the west. Contrary to expectations, the east side of Titan's stra…
The April 8, 2005, Eclipse White-Light Corona
Pasachoff, Jay M.; Rušin, Vojtech; Druckmüller, Miloslav +2 more
The hybrid solar eclipse of April 8, 2005, provided a good opportunity to observe the white-light solar corona, even though the eclipse lasted just 30 seconds and could be seen only from ships in the Pacific Ocean. During the eclipse, we detected a unique `cloud' of particles in the white-light corona above the west limb ≈260°-270°. We compare thi…