Search Publications
Evidence for two populations of classical transneptunian objects: The strong inclination dependence of classical binaries
Noll, Keith S.; Grundy, William M.; Levison, Harold F. +2 more
We have searched 101 Classical transneptunian objects for companions with the Hubble Space Telescope. Of these, at least 21 are binary. The heliocentric inclinations of the objects we observed range from 0.6°-34°. We find a very strong anticorrelation of binaries with inclination. Of the 58 targets that have inclinations of less than 5.5°, 17 are …
A Precise Proper Motion for the Crab Pulsar, and the Difficulty of Testing Spin-Kick Alignment for Young Neutron Stars
Anderson, J.; Chatterjee, S.; Kaplan, D. L. +1 more
We present a detailed analysis of archival Hubble Space Telescope data that we use to measure the proper motion of the Crab pulsar, with the primary goal of comparing the direction of its proper motion with the projected axis of its pulsar wind nebula (the projected spin axis of the pulsar). We demonstrate that our measurement, using 47 observatio…
The E-ring in the vicinity of Enceladus. II. Probing the moon's interior—The composition of E-ring particles
Kempf, S.; Postberg, F.; Srama, R. +4 more
The population of Saturn's outermost tenuous E-ring is dominated by tiny water ice particles. Active volcanism on the moon Enceladus, embedded in the E-ring, has since late 2005 been known to be a major source of particles replenishing the ring. Therefore particles in the vicinity of Enceladus may provide crucial information about the dynamical an…
Unveiling the nature of INTEGRAL objects through optical spectroscopy. VI. A multi-observatory identification campaign
Palazzi, E.; Minniti, D.; Masetti, N. +18 more
Using 8 telescopes in the northern and southern hemispheres, plus archival data from two on-line sky surveys, we performed a systematic optical spectroscopic study of 39 putative counterparts of unidentified or poorly studied INTEGRAL sources in order to determine or at least better assess their nature. This was implemented within the framework of…
On the detectability of Lyα emission in star forming galaxies. The role of dust
Östlin, G.; Hayes, M.; Mas-Hesse, J. M. +2 more
Context: Lyman-alpha (Lyα) radiation is now widely used to investigate the galaxy formation and evolution in the high redshift universe. However, without a rigorous understanding of the processes regulating the Lyα escape fraction, physical interpretations of high-z observations remain questionable.
Aims: We examine six nearby star forming gal…
Late Amazonian glaciation at the dichotomy boundary on Mars: Evidence for glacial thickness maxima and multiple glacial phases
Head, James W.; Marchant, David R.; Dickson, James L.
Lineated valley fill (LVF) in fretted valleys at the dichotomyboundary has been interpreted as glacial in origin. Unknownare (1) the original thickness of the glacier ice, (2) the amountof ice-surface lowering, through sublimation and retreat, toits presently observed level, and (3) whether there were multipleperiods of glaciation. We address thes…
The E ring in the vicinity of Enceladus. I. Spatial distribution and properties of the ring particles
Beckmann, U.; Kempf, S.; Postberg, F. +6 more
Saturn's diffuse E ring is the largest ring of the Solar System and extends from about 3.1R (Saturn radius R=60,330 km) to at least 8R encompassing the icy moons Mimas, Enceladus, Tethys, Dione, and Rhea. After Cassini's insertion into her saturnian orbit in July 2004, the spacecraft performed a number of equatorial as well as steep traversals thr…
Effects of Dust Geometry in Lyα Galaxies at z = 4.4
Finkelstein, Steven L.; Malhotra, Sangeeta; Grogin, Norman +2 more
Equivalent widths (EWs) observed in high-redshift Lyα galaxies could be stronger than the EW intrinsic to the stellar population if dust is present residing in clumps in the interstellar medium (ISM). In this scenario, continuum photons could be extinguished, while the Lyα photons would be resonantly scattered by the clumps, eventually escaping th…
On the kinematic evolution of young local associations and the Scorpius-Centaurus complex
Figueras, F.; Torra, J.; Fernández, D.
Context: Over the last decade, several groups of young (mainly low-mass) stars have been discovered in the solar neighbourhood (closer than ~100 pc), thanks to cross-correlation between X-ray, optical spectroscopy and kinematic data. These young local associations - including an important fraction whose members are Hipparcos stars - offer insights…
Metal-rich multi-phase gas in M 87. AGN-driven metal transport, magnetic-field supported multi-temperature gas, and constraints on non-thermal emission observed with XMM-Newton
Finoguenov, A.; Böhringer, H.; Simionescu, A. +2 more
We use deep (~120 ks) XMM-Newton data of the M 87 halo to analyze its spatially resolved temperature structure and chemical composition. We focus particularly on the regions of enhanced X-ray brightness associated with the inner radio lobes, which are known not to be described very well by single-temperature spectral models. Compared to a simple t…