Search Publications
Eclipsing Binary Solutions in Physical Units and Direct Distance Estimation
Wilson, R. E.
Opportunities for extraction of distances and temperatures from eclipsing binary light curves that are in standard flux units, as opposed to traditional arbitrary units, are examined. Benefits include (1) distance becomes an ordinary solution parameter with a standard error, (2) temperatures of both stars may be derivable in favorable circumstance…
Polarization of the Crab Pulsar and Nebula as Observed by the INTEGRAL/IBIS Telescope
Grenier, I. A.; Laurent, P.; Lebrun, F. +2 more
Neutron stars generate powerful winds of relativistic particles that form bright synchrotron nebulae around them. Polarimetry provides a unique insight into the geometry and magnetic configuration of the wind, but high-energy measurements have failed until recently. The INTEGRAL/IBIS telescope has been used in its Compton mode to search for linear…
The Spatial Structure of an Accretion Disk
Kochanek, Christopher S.; Poindexter, Shawn; Morgan, Nicholas
Based on the microlensing variability of the two-image gravitational lens HE 1104-1805 observed between 0.4 and 8 µm, we have measured the size and wavelength-dependent structure of the quasar accretion disk. Modeled as a power law in temperature, T propto R-β, we measure a B-band (0.13 µm in the rest frame) half-light radiu…
Magnetic Field Overlying Solar Eruption Regions and Kink and Torus Instabilities
Liu, Y.
Using a potential field source surface (PFSS) model, we study a magnetic field overlying erupted filaments in solar active regions. The filaments studied here were reported to experience a kink instability or a torus instability. The torus instability leads to a full eruption, while the kink instability leads to a full eruption or a failed eruptio…
An Integrated Picture of Star Formation, Metallicity Evolution, and Galactic Stellar Mass Assembly
Barger, A. J.; Cowie, L. L.
We present an integrated study of star formation and galactic stellar mass assembly from z = 0.05 to 1.5 and galactic metallicity evolution from z = 0.05 to 0.9 using a very large and highly spectroscopically complete sample selected by rest-frame NIR bolometric flux in the GOODS-N. We assume a Salpeter IMF and fit Bruzual & Charlot models to …
Study of Nonthermal Emission from SNR RX J1713.7-3946 with Suzaku
Petre, Robert; Kokubun, Motohide; Nakazawa, Kazuhiro +11 more
We present results obtained from a series of observations of the supernova remnant RX J1713.7-3946 by Suzaku. Hard X-rays have been detected up to ~40 keV. The hard X-ray spectra are described by a power law with photon indices of ~3.0, which is larger than those below 10 keV. The combination of the spatially integrated XIS and HXD spectra clearly…
Combining Lens Distortion and Depletion to Map the Mass Distribution of A1689
Broadhurst, Tom; Umetsu, Keiichi
We derive a projected 2D mass map of the well-studied galaxy cluster A1689 based on an entropy-regularized maximum likelihood combination of the lens magnification and distortion of red background galaxies registered in deep Subaru images. The method is not restricted to the weak regime but applies to the whole area outside the tangential critical…
The Relation between Star Formation, Morphology, and Local Density in High-Redshift Clusters and Groups
Aragón-Salamanca, Alfonso; Milvang-Jensen, Bo; Zaritsky, Dennis +17 more
We investigate how the [O II] properties and the morphologies of galaxies in clusters and groups at z = 0.4-0.8 depend on projected local galaxy density, and compare with the field at similar redshifts and clusters at low z. In both nearby and distant clusters, higher density regions contain proportionally fewer star-forming galaxies, and the aver…
Observations and Modeling of the Early Acceleration Phase of Erupting Filaments Involved in Coronal Mass Ejections
Title, Alan M.; Török, Tibor; Kliem, Bernhard +2 more
We examine the early phases of two near-limb filament destabilizations involved in coronal mass ejections (CMEs) on 2005 June 16 and July 27, using high-resolution, high-cadence observations made with the Transition Region and Coronal Explorer (TRACE), complemented by coronagraphic observations by the Mauna Loa Solar Observatory (MLSO) and the Sol…
Modeling Nonpotential Magnetic Fields in Solar Active Regions
van Ballegooijen, A. A.; DeLuca, E. E.; Bobra, M. G.
Electric currents are present in the coronae above solar active regions, producing nonpotential magnetic fields that can be approximated as nonlinear force-free fields (NLFFFs). In this paper NLFFF models for two active regions observed in 2002 June are presented. The models are based on magnetograms from SOHO MDI and are constrained by nonpotenti…