Search Publications
A Coherent Timing Solution for the Nearby Isolated Neutron Star RX J0720.4-3125
van Kerkwijk, M. H.; Kaplan, D. L.
We present the results of a dedicated effort to measure the spin-down rate of the nearby isolated neutron star RX J0720.4-3125. Comparing arrival times of the 8.39 s pulsations for data from Chandra, we derive an unambiguous timing solution for RX J0720.4-3125 that is accurate to <0.1 cycles over >5 years. Adding data from XMM and ROSAT, the…
X-Ray Properties of Lyman Break Galaxies in the Great Observatories Origins Deep Survey
Lehmer, B. D.; Alexander, D. M.; Giavalisco, M. +9 more
We constrain the X-ray emission properties of Lyman break galaxies (LBGs) at z~3-6 using the ~2 Ms Chandra Deep Field North and ~1 Ms Chandra Deep Field South. Large samples of LBGs were discovered using the Hubble Space Telescope as part of the Great Observatories Origins Deep Survey (GOODS). Deep optical and X-ray imaging over the GOODS fields h…
The exceptional X-ray variability of the dwarf Seyfert nucleus NGC 4395
Iwasawa, K.; Vaughan, S.; Fabian, A. C. +1 more
An analysis of the X-ray variability of the low-luminosity Seyfert nucleus NGC 4395, based on a long XMM-Newton observation, is presented. The power spectrum shows a clear break from a flat spectrum (α~ 1) to a steeper spectrum (α~ 2) at a frequency fbr= 0.5-3.0 × 10-3 Hz, comparable to the highest characteristic frequency fo…
Moving Magnetic Features as Prolongation of Penumbral Filaments
Martínez Pillet, V.; Sainz Dalda, A.
A sequence of 633 high spatial resolution magnetograms and continuum images from SOHO MDI of NOAA AR 0330 is used to study moving magnetic feature (MMF) activity in the moat surrounding a mature leader sunspot. The time-averaged frame shows that the moat region is covered by a magnetic field that exhibits the same polarity distribution as that obs…
Variations of the Mid-Infrared Emission Spectrum in Reflection Nebulae
Temi, Pasquale; Bregman, Jesse
Using spatial-spectral data cubes of reflection nebulae obtained by ISOCAM, we have observed a shift in the central wavelength of the 7.7 µm band within several reflection nebulae. This band, composed of components at 7.85 and 7.65 µm, shows a centroid shift from 7.75 µm near the edge of the nebulae to 7.65 µm toward the ce…
Mid-infrared detection of large longitudinal asymmetries in Io's SO 2 atmosphere
Lellouch, Emmanuel; Spencer, John R.; Richter, Matthew J. +4 more
We have observed about 16 absorption lines of the ν SO 2 vibrational band on Io, in disk-integrated 19-µm spectra taken with the TEXES high spectral resolution mid-infrared spectrograph at the NASA Infrared Telescope Facility in November 2001, December 2002, and January 2004. These are the first ground-based infrared observations …
A substellar companion around the intermediate-mass giant star HD 11977
Pasquini, L.; de Medeiros, J. R.; Hatzes, A. P. +6 more
We report the discovery of a substellar companion to the intermediate-mass star
Periodic intensity variations in global ENA images of Saturn
Krimigis, S. M.; Mitchell, D. G.; Paranicas, C. +4 more
During select time periods in orbit about Saturn, Cassini's Ion and Neutral Camera (INCA) has detected a periodic global ENA signal. Images taken during such periods reveal the presence of a rotating source component in addition to a steady-state component; both components have peak brightness in the midnight sector, when viewed from near dawn. We…
Jupiter Thermospheric General Circulation Model (JTGCM): Global structure and dynamics driven by auroral and Joule heating
Waite, J. H.; Gladstone, G. R.; Bougher, S. W. +1 more
A growing multispectral database plus recent Galileo descent measurements are being used to construct a self-consistent picture of the Jupiter thermosphere/ionosphere system. The proper characterization of Jupiter's upper atmosphere, embedded ionosphere, and auroral features requires the examination of underlying processes, including the feedbacks…
XMM-Newton observations of the Lockman Hole. III. A relativistic Fe line in the mean X-ray spectra of type-1 and type-2 AGN
Finoguenov, A.; Streblyanska, A.; Barcons, X. +3 more
Using the 770 ks XMM-Newton survey of the Lockman Hole field in combination with extensive optical identifications of the AGN population, we derive an average rest-frame spectrum of AGN types-1 and 2. The most prominent feature in the averaged spectrum is a strong fluorescent Fe line. In both type-1 and type-2 AGN, a clear relativistic line profil…