Search Publications
Missions
Journals
Publication Years
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…
Statistical analysis of injection/dispersion events in Saturn's inner magnetosphere
Chen, Y.; Hill, T. W.
In the inner magnetosphere of a rapidly rotating planet such as Jupiter and Saturn, radial transport of plasma mainly comprises hot, tenuous plasma moving inward and cold, denser plasma moving outward. A distinctive phenomenon resulting from the drift dispersion of injecting hot plasma provides direct evidence for this convective motion. Particle …
A study of X-ray flares - I. Active late-type dwarfs
Pandey, J. C.; Singh, K. P.
We present temporal and spectral characteristics of X-ray flares observed from six late-type G-K active dwarfs (V368Cep, XIBoo, IMVir, V471Tau, CCEri and EPEri) using data from observations with the XMM-Newton observatory. All the stars were found to be flaring frequently and altogether a total of 17 flares were detected above the `quiescent' stat…
Can We Improve the Preprocessing of Photospheric Vector Magnetograms by the Inclusion of Chromospheric Observations?
Schrijver, C. J.; Wiegelmann, T.; Metcalf, T. R. +2 more
The solar magnetic field is key to understanding the physical processes in the solar atmosphere. Nonlinear force-free codes have been shown to be useful in extrapolating the coronal field upward from underlying vector boundary data. However, we can only measure the magnetic field vector routinely with high accuracy in the photosphere, and unfortun…