Search Publications
Unveiling Obscured Accretion in the Chandra Deep Field-South
Pozzi, F.; Fiore, F.; Vignali, C. +10 more
We make use of deep HST, VLT, Spitzer, and Chandra data on the Chandra Deep Field-South to constrain the number of Compton-thick AGNs in this field. We show that sources with high 24 µm-to-optical flux ratios and red colors form a distinct source population, and that their infrared luminosity is dominated by AGN emission. Analysis of the X-r…
Hinode SOT Observations of Solar Quiescent Prominence Dynamics
Tsuneta, Saku; Shimizu, Toshifumi; Okamoto, Takenori J. +9 more
We report findings from multihour 0.2'' resolution movies of solar quiescent prominences (QPs) observed with the Solar Optical Telescope (SOT) on the Hinode satellite. The observations verify previous findings of filamentary downflows and vortices in QPs. SOT observations also verify large-scale transverse oscillations in QPs, with periods of 20-4…
Recent Structural Evolution of Early-Type Galaxies: Size Growth from z = 1 to z = 0
Franx, Marijn; Illingworth, Garth D.; van der Wel, Arjen +4 more
Strong size and internal density evolution of early-type galaxies between z ~ 2 and the present has been reported by several authors. Here we analyze samples of nearby and distant (z ~ 1) galaxies with dynamically measured masses in order to confirm the previous, model-dependent results and constrain the uncertainties that may play a role. Velocit…
Small-Scale Energy Cascade of the Solar Wind Turbulence
Alexandrova, O.; Carbone, V.; Veltri, P. +1 more
Magnetic fluctuations in the solar wind are distributed according to Kolmogorov's power law f-5/3 below the ion cyclotron frequency fci. Above this frequency, the observed steeper power law is usually interpreted in two different ways, as a dissipative range of the solar wind turbulence, or another turbulent cascade, the natu…
Theoretical Spectra and Light Curves of Close-in Extrasolar Giant Planets and Comparison with Data
Burrows, A.; Budaj, J.; Hubeny, I.
We present theoretical atmosphere, spectral, and light-curve models for extrasolar giant planets (EGPs) undergoing strong irradiation for which Spitzer planet/star contrast ratios or light curves have been published (circa 2007 June). These include HD 209458b, HD 189733b, TrES-1, HD 149026b, HD 179949b, and υ And b. By comparing models with data, …
Variations of the Mid-IR Aromatic Features inside and among Galaxies
Madden, Suzanne C.; Jones, Anthony P.; Galliano, Frédéric +2 more
We present the results of a systematic study of mid-IR spectra of Galactic regions, Magellanic H II regions, and galaxies of various types (dwarf, spiral, starburst), observed by the satellites ISO and Spitzer. We study the relative variations of the 6.2, 7.7, 8.6, and 11.3 µm features inside spatially resolved objects (such as M82, M51, 30 …
Ground-based detection of sodium in the transmission spectrum of exoplanet HD 209458b
Snellen, I. A. G.; Albrecht, S.; Le Poole, R. S. +1 more
Context: The first detection of an atmosphere around an extrasolar planet was presented by Charbonneau and collaborators in 2002. In the optical transmission spectrum of the transiting exoplanet HD 209458b, an absorption signal from sodium was measured at a level of 0.023 ± 0.006%, using the STIS spectrograph on the Hubble Space Telescope. Despite…
AGB variables and the Mira period-luminosity relation
Whitelock, Patricia A.; Feast, Michael W.; Van Leeuwen, Floor
Published data for large-amplitude asymptotic giant branch variables in the Large Magellanic Cloud (LMC) are re-analysed to establish the constants for an infrared (K) period-luminosity relation of the form MK=ρ[log P- 2.38]+δ. A slope of ρ=-3.51 ± 0.20 and a zero-point of δ=-7.15 ± 0.06 are found for oxygen-rich Miras (if a distance mo…
Evidence for Quasar Activity Triggered by Galaxy Mergers in HST Observations of Dust-reddened Quasars
Lacy, Mark; Becker, Robert H.; Urrutia, Tanya
We present Hubble Space Telescope ACS images of 13 dust-reddened type 1 quasars selected from the FIRST/2MASS Red Quasar Survey. These quasars have high intrinsic luminosities after correction for dust obscuration (-23.5 >= MB >= - 26.2 from K-magnitude). The images show strong evidence of recent or ongoing interaction in 11 of th…
CoRoT Measures Solar-Like Oscillations and Granulation in Stars Hotter Than the Sun
Neiner, Coralie; Baudin, Frédéric; Aerts, Conny +41 more
Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measur…