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The composition of Saturn's E ring
Kempf, S.; Postberg, F.; Srama, R. +7 more
We present the first in situ direct measurement of the composition of particles in Saturn's rings. The Cassini cosmic dust analyser (CDA) measured the mass spectra of nearly 300 impacting dust particles during the 2004 October E ring crossing. An initial interpretation of the data shows that the particles are predominantly water ice, with minor co…
Testing the accuracy of synthetic stellar libraries
Coelho, Paula; Martins, Lucimara P.
One of the main ingredients of stellar population synthesis models is a library of stellar spectra. Both empirical and theoretical libraries are used for this purpose, and the question about which one is preferable is still debated in the literature. Empirical and theoretical libraries are being improved significantly over the years, and many libr…
Modulation of Saturn's radio clock by solar wind speed
Lamy, Laurent; Prangé, Renée; Cecconi, Baptiste +2 more
The internal rotation rates of the giant planets can be estimated by cloud motions, but such an approach is not very precise because absolute wind speeds are not known a priori and depend on latitude: periodicities in the radio emissions, thought to be tied to the internal planetary magnetic field, are used instead. Saturn, despite an apparently a…
A deeper search for the progenitor of the Type Ic supernova 2002ap
Smartt, S. J.; Young, D. R.; Maund, J. R. +6 more
Images of the site of the Type Ic supernova (SN) 2002ap taken before explosion were analysed previously by Smartt et al. We have uncovered new unpublished, archival pre-explosion images from the Canada-France-Hawaii Telescope (CFHT) that are vastly superior in depth and image quality. In this paper we present a further search for the progenitor st…
The Mass of the Candidate Exoplanet Companion to HD 33636 from Hubble Space Telescope Astrometry and High-Precision Radial Velocities
Bizyaev, Dmitry; Smith, Verne V.; Harrison, Thomas E. +4 more
We have determined a dynamical mass for the companion to HD 33636 that indicates it is a low-mass star instead of an exoplanet. Our result is based on an analysis of Hubble Space Telescope (HST) astrometry and ground-based radial velocity data. We have obtained high-cadence radial velocity measurements spanning 1.3 yr of HD 33636 with the Hobby-Eb…
The XMM-Large Scale Structure catalogue: X-ray sources and associated optical data. Version I
Maccagni, D.; Chiappetti, L.; Altieri, B. +34 more
Following the presentation of the XMM-Large Scale Structure (XMM-LSS) survey X-ray source detection package by Pacaud et al., we provide the source lists for the first surveyed 5.5deg2. The catalogues pertain to the [0.5-2] and [2-10] keV bands and contain in total 3385 point-like or extended sources above a detection likelihood of 15 i…
Spectroscopy of z ~ 6 i-Dropout Galaxies: Frequency of Lyα Emission and the Sizes of Lyα-emitting Galaxies1,
Rosati, P.; van der Wel, A.; Bouwens, R. J. +8 more
We report on deep spectroscopy, using LRIS on Keck I and FORS2 on the VLT, of a sample of 22 candidate z~6 Lyman break galaxies (LBGs) selected by the i775-z850>1.3 dropout criterion. Redshifts could be measured for eight objects. These redshifts are all in the range z=5.5-6.1, confirming the efficiency of the i775
An X-Ray Census of Young Stars in the Massive Southern Star-forming Complex NGC 6357
Tsujimoto, Masahiro; Garmire, Gordon P.; Feigelson, Eric D. +4 more
We present the first high spatial resolution X-ray study of the massive star-forming region NGC 6357, obtained in a 38 ks Chandra/ACIS observation. Inside the brightest constituent of this large H II region complex is the massive open cluster Pismis 24. It contains two of the brightest and bluest stars known, yet remains poorly studied; only a han…
Spectral Properties from Lyα to Hα for an Essentially Complete Sample of Quasars. I. Data
Wills, D.; Shang, Zhaohui; Brotherton, Michael S. +1 more
We have obtained quasi-simultaneous ultraviolet-optical spectra for 22 out of 23 quasars in the complete Palomar-Green X-ray sample with redshift z<0.4 and MB<-23. The spectra cover rest-frame wavelengths from at least Lyα to Hα. Here we provide a detailed description of the data, including careful spectrophotometry and redshift d…
A limit on the presence of Earth-mass planets around a Sun-like star
Steffen, Jason H.; Agol, Eric
We present a combined analysis of all publicly available visible Hubble Space Telescope observations of transits of the planet HD 209458b. We derive the times of transit, planet radius, inclination, period, and ephemeris. We then use the times of transit to place constraints on the existence of secondary planets in the system. We show that planets…