Search Publications
Multispacecraft observations of chorus dispersion and source location
Kletzing, Craig A.; Pickett, Jolene; Chum, Jaroslav +3 more
We report Cluster Wideband Data (WBD) receiver observations of correlated chorus elements with different frequency/time characteristics as seen on multiple spatially separated Cluster spacecraft. Because chorus packets disperse as they propagate, careful comparison of the signals from multiple spacecraft can provide new information about the origi…
Energetic particle observations by Ulysses during the declining phase of solar cycle 23
Forsyth, R. J.; Lanzerotti, L. J.; Marsden, R. G. +4 more
We present recent energetic particle measurements from 1-20 MeV/n recorded by the Ulysses/COSPIN/LET instrument from mid-October to the end of November 2003 and from May 2004 to the end of February 2005. Long-lasting periods with enhanced solar activity occurred during the declining phase of the current solar cycle contributing to the high-intensi…
Are the E-type asteroids (2867) Steins, a target of the Rosetta mission, and NEA (3103) Eger remnants of an old asteroid family?
Barucci, M. A.; Fornasier, S.; Marzari, F. +2 more
Aims:We have investigated the spectral properties of the E-type asteroids 2867 Steins, a main belt object target of the Rosetta mission, and 3103 Eger, a near Earth asteroid. The strong spectral similarity between these two objects suggests a possible common origin in spite of their presently different orbits. We explore the possibility that Stein…
Atomic data for radioactive elements Ra I, Ra II, Ac I and Ac II and application to their detection in HD 101065 and HR 465
Quinet, P.; Fivet, V.; Yushchenko, A. V. +3 more
Radiative data for transitions of astrophysical interest in radioactive elements Ra I, Ra II, Ac I and Ac II have been computed using a semi-empirical relativistic Hartree-Fock approach including core polarization effects. Most of the oscillator strengths reported in the present paper are new. A possible detection of radium (Ra II) and actinium (A…
Variability of Moderate-Luminosity Active Galactic Nuclei at z = 0.36
Treu, Tommaso; Malkan, Matthew A.; Woo, Jong-Hak +2 more
We monitored 13 moderate-luminosity active galactic nuclei at z=0.36 to measure flux variability, explore feasibility of reverberation mapping, and determine uncertainties on estimating black hole mass from single-epoch data. Spectra and images were obtained with approximately weekly cadence for up to 4 months, using the Kast spectrograph on the 3…
The Variation of Magnesium Depletion with Line-of-Sight Conditions
Snow, Theodore P.; Jensen, Adam G.
In this paper we report on the gas-phase abundance of singly ionized magnesium (Mg II) in 44 lines of sight, using data from the Hubble Space Telescope (HST). We measure Mg II column densities by analyzing medium- and high-resolution archival Space Telescope Imaging Spectrograph (STIS) spectra of the 1240 Å doublet of Mg II. We find that Mg II dep…
Spectroscopic Study of Kepler Asteroseismic Targets
Frasca, A.; Latham, D. W.; Jerzykiewicz, M. +1 more
Reported are spectroscopic observations of 15 candidates for Kepler primary asteroseismic targets and 14 other stars in the Kepler field, carried out at three observatories. For all these stars, the radial velocities, effective temperature, surface gravity, metallicity, and the projected rotational velocity are derived from two separate sets of da…
The exceptionally extended flaring activity in the X-ray afterglow of GRB 050730 observed with Swift and XMM-Newton
Troja, E.; Campana, S.; Tagliaferri, G. +27 more
Aims: We observed the high redshift (z = 3.969) GRB 050730 with Swift and XMM-Newton to study its prompt and afterglow emission.
Methods: We carried out a detailed spectral and temporal analysis of Swift and XMM-Newton observations.
Results: The X-ray afterglow of GRB 050730 was found to decline along with time with superimposed intense fl…
X-Ray Localization of the Globular Cluster G1 with XMM-Newton
Kong, Albert K. H.
We present an accurate X-ray position of the massive globular cluster G1 obtained using XMM-Newton and the Hubble Space Telescope (HST). The X-ray emission of G1 has been detected recently with XMM-Newton. There are two possibilities for the origin of the X-ray emission: it could be due to either accretion of the central intermediate-mass black ho…
Long term hard X-ray variability of the anomalous X-ray pulsar 1RXS J170849.0-400910 discovered with INTEGRAL
Tiengo, A.; Götz, D.; Mereghetti, S. +6 more
Aims:We report on a multi-band high-energy observing campaign aimed at studying the long term spectral variability of the Anomalous X-ray Pulsar (AXP) 1RXS J170849.0-400910, one of the magnetar candidates.
Methods: We observed 1RXS J170849.0-400910 in Fall 2006 and Spring 2007 simultaneously with Swift/XRT, in the 0.1-10 keV energy range, and …