Search Publications
Asteroids 2867 Steins and 21 Lutetia: surface composition from far infrared observations with the Spitzer space telescope
Jorda, L.; Lamy, P. L.; Barucci, M. A. +8 more
Aims:The aim of this paper is to investigate the surface composition of the two asteroids 21 Lutetia and 2867 Steins, targets of the Rosetta space mission.
Methods: We observed the two asteroids through their full rotational periods with the Infrared Spectrograph of the Spitzer Space Telescope to investigate the surface properties. The analysi…
Thermal convection in ice-I shells of Titan and Enceladus
Showman, Adam P.; Mitri, Giuseppe
Cassini-Huygens observations have shown that Titan and Enceladus are geologically active icy satellites. Mitri and Showman [Mitri, G., Showman, A.P., 2005. Icarus 177, 447-460] and McKinnon [McKinnon, W.B., 2006. Icarus 183, 435-450] investigated the dynamics of an ice shell overlying a pure liquid-water ocean and showed that transitions from a co…
X-Ray Observations of Parsec-scale Tails behind Two Middle-Aged Pulsars
Garmire, G. P.; Pavlov, G. G.; Kargaltsev, O. +2 more
Chandra and XMM-Newton resolved extremely long tails behind two middle-aged pulsars, J1509-5850 and J1740+1000. The tail of PSR J1509-5850 is discernible up to 5.6' from the pulsar, which corresponds to the projected length l⊥ = 6.5d4 pc, where d = 4d4 kpc is the distance to the pulsar. The observed tail flux is 2 …
High-Ionization Mid-Infrared Lines as Black Hole Mass and Bolometric Luminosity Indicators in Active Galactic Nuclei
Lutz, D.; Sturm, E.; Helou, G. +6 more
We present relations of the black hole mass and the optical luminosity with the velocity dispersion and the luminosity of the [Ne V] and the [O IV] high-ionization lines in the mid-infrared (MIR) for 28 reverberation-mapped active galactic nuclei. We used high-resolution Spitzer Infrared Spectrograph and Infrared Space Observatory Short Wavelength…
Monte Carlo model of electron transport for the calculation of Mars dayglow emissions
Leblanc, F.; Gérard, J. -C.; Shematovich, V. I. +3 more
A model of the photoelectron collision-induced component of the Mars dayglow using recent cross sections and solar flux is described. The calculation of the photoelectron source of excitation is based on a stochastic solution of the Boltzmann equation using the direct simulation Monte Carlo method. The neutral atmosphere is taken from outputs of a…
The Formation of Coronal Loops by Thermal Instability in Three Dimensions
Linker, Jon A.; Mikić, Zoran; Mok, Yung +1 more
Plasma loops in solar active regions have been observed in EUV and soft X-rays for decades. Their formation mechanism and properties, however, are still not fully understood. Predictions by early models, based on 1D hydrostatic equilibria with uniform plasma heating, are not consistent with high-resolution measurements. In this Letter, we demonstr…
A New Determination of the High-Redshift Type Ia Supernova Rates with the Hubble Space Telescope Advanced Camera for Surveys
Wang, L.; Lidman, C.; Amanullah, R. +28 more
We present a new measurement of the volumetric rate of SNe Ia up to a redshift of 1.7, using the HST GOODS data combined with an additional HST data set covering the GOODS-North field collected in 2004. We employ a novel technique that does not require spectroscopic data for identifying SNe Ia (although spectroscopic measurements of redshifts are …
Relativistic Iron Line Emission from the Neutron Star Low-Mass X-Ray Binary 4U 1636-536
Kaaret, Philip; Pandel, Dirk; Corbel, Stephane
We present an analysis of XMM-Newton and RXTE data from three observations of the neutron star LMXB 4U 1636-536. The X-ray spectra show clear evidence of a broad, asymmetric iron emission line extending over the energy range 4-9 keV. The line profile is consistent with relativistically broadened Fe Kα emission from the inner accretion disk. The Fe…
HST/WFPC2 Imaging of the Circumnuclear Structure of Low-Luminosity Active Galactic Nuclei. I. Data and Nuclear Morphology
Pérez, Enrique; Cid Fernandes, Roberto; González Delgado, Rosa M. +1 more
In several studies of low-luminosity active galactic nuclei (LLAGNs), we have characterized the properties of the stellar populations in LINERs and LINER/H II transition objects (TOs). We have found a populous class of galactic nuclei which stand out because of their conspicuous 0.1-1 Gyr populations. These nuclei are called "Young-TOs" since they…
The correlation between blue straggler and binary fractions in the core of Galactic globular clusters
Beccari, G.; Ferraro, F. R.; Fusi Pecci, F. +2 more
Context: Blue stragglers stars (BSSs) are thought to form in globular clusters by two main formation channels: i) mergers induced by stellar collisions; and ii) coalescence or mass transfer between companions in binary systems. The detailed study of the BSS properties is therefore crucial for understanding the binary evolution mechanisms and the c…