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Composition of Titan's ionosphere
Luhmann, J. G.; Wahlund, J. -E.; Ip, W. -H. +13 more
We present Cassini Ion and Neutral Mass Spectrometer (INMS) measurements of ion densities on the nightside of Titan from April 16, 2005, and show that a substantial ionosphere exists on the nightside and that complex ion chemistry is operating there. The total ionospheric densities measured both by the INMS and the Cassini Radio and Plasma Wave (R…
Exploring Brown Dwarf Disks: A 1.3 mm Survey in Taurus
Wood, Kenneth; Jayawardhana, Ray; Scholz, Alexander
We have carried out sensitive 1.3 mm observations of 20 young brown dwarfs in the Taurus star-forming region, representing the largest sample of young substellar objects targeted in a deep millimeter-continuum survey to date. Under standard assumptions, the masses of brown dwarf disks range from <~0.4 to several Jupiter masses. Their relative d…
V0332+53 in the outburst of 2004-2005: luminosity dependence of the cyclotron line and pulse profile
Sunyaev, R. A.; Tsygankov, S. S.; Lutovinov, A. A. +1 more
We present the results of observations of the transient X-ray pulsar V0332+53 performed during a very powerful outburst, from 2004 December to 2005 February, with the INTEGRAL and RXTE observatories in a wide (3-100 keV) energy band. A cyclotron resonance scattering line at an energy of ~26 keV has been detected in the source spectrum together wit…
Single-spacecraft detection of rolled-up Kelvin-Helmholtz vortices at the flank magnetopause
RèMe, H.; Hasegawa, H.; Fujimoto, M. +3 more
Recent numerical simulations suggest that as soon as the Kelvin-Helmholtz instability (KHI) has grown nonlinearly to form a highly rolled-up vortex, plasma mixing is inevitably achieved within the vortex. Identification of rolled-up vortices by in situ measurements is therefore an important task as a step to establish the mechanism by which solar …
Spitzer IRAC Confirmation of z850-Dropout Galaxies in the Hubble Ultra Deep Field: Stellar Masses and Ages at z ~ 7
Labbé, Ivo; Illingworth, G. D.; Franx, M. +1 more
Using Spitzer IRAC mid-infrared imaging from the Great Observatories Origins Deep Survey, we study z850-dropout sources in the Hubble Ultra Deep Field. After carefully removing contaminating flux from foreground sources, we clearly detect two z850 dropouts at 3.6 and 4.5 µm, while two others are marginally detected. The…
Ground-based CCD astrometry with wide field imagers. I. Observations just a few years apart allow decontamination of field objects from members in two globular clusters
Anderson, J.; Bedin, L. R.; Piotto, G. +2 more
This paper is the first of a series of papers in which we will apply the methods we have developed for high-precision astrometry (and photometry) with the Hubble Space Telescope (HST) to the case of wide-field ground-based images. In particular, we adapt the software originally developed for WFPC2 to ground-based, wide field images from the WFI at…
Discovery of an Extraordinarily Massive Cluster of Red Supergiants
MacKenty, John W.; Figer, Donald F.; Kudritzki, Rolf P. +4 more
We report the discovery of an extraordinarily massive young cluster of stars in the Galaxy, having an inferred total initial cluster mass comparable to the most massive young clusters in the Galaxy. Using IRMOS, 2MASS, and Spitzer observations, we conclude that there are 14 red supergiants in the cluster, compared with five, in what was previously…
The Morphological Diversities among Star-forming Galaxies at High Redshifts in the Great Observatories Origins Deep Survey
Papovich, Casey; Dickinson, Mark; Ferguson, Henry C. +8 more
We used the deep, multiwavelength images obtained by the Great Observatories Origins Deep Survey (GOODS) to identify ~4700 Lyman break galaxies (LBGs) at z>2.5, and 292 starburst galaxies at z~1.2. We present the results from morphological analysis based on light profile shape and ellipticity for ~1333 of the most luminous LBGs. About 40% of LB…
The Calm before the Storm: The Link between Quiescent Cavities and Coronal Mass Ejections
de Toma, G.; Gibson, S. E.; Burkepile, J. +2 more
Determining the state of the corona prior to CMEs is crucial to understanding and ultimately predicting solar eruptions. A common and compelling feature of CMEs is their three-part morphology, as seen in white-light observations of a bright expanding loop, followed by a relatively dark cavity, and finally a bright core associated with an erupting …
Unveiling the nature of INTEGRAL objects through optical spectroscopy. V. Identification and properties of 21 southern hard X-ray sources
Palazzi, E.; Minniti, D.; Masetti, N. +13 more
Optical spectroscopic identification of the nature of 21 unidentified southern hard X-ray objects is reported here in the framework of our campaign aimed at determining the nature of newly-discovered and/or unidentified sources detected by INTEGRAL. Our results show that 5 of these objects are magnetic Cataclysmic Variables (CVs), 4 are High-Mass …