Search Publications
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…
Astrophysical parameters of Galactic open clusters
Scholz, R. -D.; Piskunov, A. E.; Kharchenko, N. V. +2 more
We present a catalogue of astrophysical data for 520 Galactic open clusters. These are the clusters for which at least three most probable members (18 on average) could be identified in the ASCC-2.5, a catalogue of stars based on the Tycho-2 observations from the Hipparcos mission. We applied homogeneous methods and algorithms to determine angular…
In situ measurements of the physical characteristics of Titan's environment
Neubauer, F. M.; Rodrigo, R.; Barucci, M. A. +40 more
On the basis of previous ground-based and fly-by information, we knew that Titan's atmosphere was mainly nitrogen, with some methane, but its temperature and pressure profiles were poorly constrained because of uncertainties in the detailed composition. The extent of atmospheric electricity (`lightning') was also hitherto unknown. Here we report t…
Wave acceleration of electrons in the Van Allen radiation belts
Meredith, Nigel P.; Horne, Richard B.; Glauert, Sarah A. +11 more
The Van Allen radiation belts are two regions encircling the Earth in which energetic charged particles are trapped inside the Earth's magnetic field. Their properties vary according to solar activity and they represent a hazard to satellites and humans in space. An important challenge has been to explain how the charged particles within these bel…
Spitzer View on the Evolution of Star-forming Galaxies from z = 0 to z ~ 3
Papovich, Casey; Pérez-González, Pablo G.; Rieke, George H. +11 more
We use a 24 µm-selected sample containing more than 8000 sources to study the evolution of star-forming galaxies in the redshift range from z=0 to z~3. We obtain photometric redshifts for most of the sources in our survey using a method based on empirically built templates spanning from ultraviolet to mid-infrared wavelengths. The accuracy o…
The Effective Temperature Scale of FGK Stars. II. Teff:Color:[Fe/H] Calibrations
Meléndez, Jorge; Ramírez, Iván
We present up-to-date metallicity-dependent temperature versus color calibrations for main-sequence and giant stars based on temperatures derived with the infrared flux method (IRFM). Seventeen colors in the photometric systems UBV, uvby, Vilnius, Geneva, RI(Cousins), DDO, Hipparcos-Tycho, and Two Micron All Sky Survey (2MASS) have been calibrated…
Optimization of Starburst99 for Intermediate-Age and Old Stellar Populations
Leitherer, Claus; Vázquez, Gerardo A.
We have incorporated the latest release of the Padova models into the evolutionary synthesis code Starburst99. The Padova tracks were extended to include the full asymptotic giant branch (AGB) evolution until the final thermal pulse over the mass range 0.9-5 Msolar. With this addition, Starburst99 accounts for all stellar phases that co…