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Phyllosilicates on Mars and implications for early martian climate
Mangold, N.; Bibring, J. -P.; Arvidson, R. E. +6 more
The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer o…
Passively Evolving Early-Type Galaxies at 1.4 <~ z <~ 2.5 in the Hubble Ultra Deep Field
Cimatti, A.; Daddi, E.; Panagia, N. +13 more
We report on a complete sample of seven luminous early-type galaxies in the Hubble Ultra Deep Field (UDF) with spectroscopic redshifts between 1.39 and 2.47, and to KAB<23. Using the BzK selection criterion, we have preselected a set of objects over the UDF, which fulfill the photometric conditions for being passively evolving galaxi…
Confined and Ejective Eruptions of Kink-unstable Flux Ropes
Török, T.; Kliem, B.
The ideal helical kink instability of a force-free coronal magnetic flux rope, anchored in the photosphere, is studied as a model for solar eruptions. Using the flux rope model of Titov and Démoulin as the initial condition in MHD simulations, both the development of helical shape and the rise profile of a confined (or failed) filament eruption (o…
The Relationship between Luminosity and Broad-Line Region Size in Active Galactic Nuclei
Kaspi, Shai; Peterson, Bradley M.; Maoz, Dan +3 more
We reinvestigate the relationship between the characteristic broad-line region size (RBLR) and the Balmer emission-line, X-ray, UV, and optical continuum luminosities. Our study makes use of the best available determinations of RBLR for a large number of active galactic nuclei (AGNs) from Peterson et al. Using their determina…
A comprehensive range of X-ray ionized-reflection models
Fabian, A. C.; Ross, R. R.
X-ray ionized reflection occurs when a surface is irradiated with X-rays so intense that its ionization state is determined by the ionization parameter ξ~F/n, where F is the incident flux and n the gas density. It occurs in accretion, on to compact objects including black holes in both active galaxies and stellar-mass binaries, and possibly in gam…
The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe
Israel, G.; Atreya, S. K.; Lunine, J. I. +15 more
Saturn's largest moon, Titan, remains an enigma, explored only by remote sensing from Earth, and by the Voyager and Cassini spacecraft. The most puzzling aspects include the origin of the molecular nitrogen and methane in its atmosphere, and the mechanism(s) by which methane is maintained in the face of rapid destruction by photolysis. The Huygens…
Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres. I. High-Energy Irradiances (1-1700 Å)
Güdel, Manuel; Guinan, Edward F.; Audard, Marc +1 more
We report on the results of the Sun in Time multiwavelength program (X-rays to UV) of solar analogs with ages covering ~0.1-7 Gyr. The chief science goals are to study the solar magnetic dynamo and to determine the radiative and magnetic properties of the Sun during its evolution across the main sequence. The present paper focuses on the latter go…
Resolved Massive Star Clusters in the Milky Way and Its Satellites: Brightness Profiles and a Catalog of Fundamental Parameters
van der Marel, Roeland P.; McLaughlin, Dean E.
We present a database of structural and dynamical properties for 153 spatially resolved star clusters in the Milky Way, the Large and Small Magellanic Clouds, and the Fornax dwarf spheroidal. This database complements and extends others in the literature, such as those of Harris and Mackey & Gilmore. Our cluster sample comprises 50 ``young mas…
Luminosity-dependent evolution of soft X-ray selected AGN. New Chandra and XMM-Newton surveys
Hasinger, G.; Schmidt, M.; Miyaji, T.
We present new results on the cosmological evolution of unabsorbed (type-1) active galactic nuclei (AGN) selected in the soft (0.5-2 keV) X-ray band. From a variety of ROSAT, XMM-Newton and Chandra surveys we selected a total of ~1000 AGN with an unprecedented spectroscopic and photometric optical/NIR identification completeness. For the first tim…
Star counts in the Galaxy. Simulating from very deep to very shallow photometric surveys with the TRILEGAL code
Hatziminaoglou, E.; Girardi, L.; Groenewegen, M. A. T. +1 more
We describe TRILEGAL, a new populations synthesis code for simulating the stellar photometry of any Galaxy field. The code attempts to improve upon several technical aspects of star count models, by: dealing with very complete input libraries of evolutionary tracks; using a stellar spectral library to simulate the photometry in virtually any broad…