Search Publications
From Exoplanets to Quasars: Detection of Potential Damped Lyα Absorbing Galaxies Using Angular Differential Imaging
Ellison, Sara L.; Johnson-Groh, Mara; Marois, Christian
The advantages of angular differential imaging (ADI) have been previously untested in imaging the host galaxies of damped Lyα (DLA) systems. In this pilot study, we present the first application of ADI to directly image the host galaxy of the DLA seen toward the quasar J1431+3952. K-band imaging of the field surrounding J1431+3952 was obtained on …
XMM-Newton and Chandra Observations of the Filled-center Supernova Remnant G63.7+1.1
Safi-Harb, S.; Kothes, R.; Matheson, H.
Pulsar wind nebulae (PWNe) provide unique opportunities to study relativistic pulsar winds and their interaction with the surrounding medium. G63.7+1.1 is an intriguing supernova remnant studied so far only at radio wavelengths and classified as a PWN candidate based on its nonthermal radio emission. We present the first X-ray study of G63.7+1.1, …
Tomographic Separation of Composite Spectra. XII. The Physical Properties and Spectral Phase Variability of the Massive Close Binary HD 159176
Penny, Laura R.; Epps, Jacob G.; Snyder, Joseph D.
We present our analysis of the double-lined, O-binary HD 159176 based on observations made with the International Ultraviolet Explorer (IUE). We use cross-correlation methods to obtain radial velocities, confirm the orbital elements, and estimate the UV flux ratio. In addition, we cross-correlate specific regions of the IUE spectra corresponding t…
The XMM-Newton1 and INTEGRAL2 Observations of the Supergiant Fast X-Ray Transient IGR J16328-4726
Piro, L.; Bird, A. J.; Fiocchi, M. +6 more
The accretion mechanism producing the short flares observed from the Supergiant Fast X-ray Transients (SFXT) is still highly debated and forms a major part in our attempts to place these X-ray binaries in the wider context of the High Mass X-ray Binaries. We report on a 216 ks INTEGRAL observation of the SFXT IGR J16328-4726 (2014 August 24-27) si…
The Effects of Spatial Smoothing on Solar Magnetic Helicity Parameters and the Hemispheric Helicity Sign Rule
Petrie, Gordon; Ocker, Stella Koch
The hemispheric preference for negative/positive helicity to occur in the northern/southern solar hemisphere provides clues to the causes of twisted, flaring magnetic fields. Previous studies on the hemisphere rule may have been affected by seeing from atmospheric turbulence. Using Hinode/SOT-SP data spanning 2006-2013, we studied the effects of t…
Dusty Quasars at High Redshifts
Weedman, Daniel; Sargsyan, Lusine
A population of quasars at z ∼ 2 is determined based on dust luminosities νL ν (7.8 µm) that includes unobscured, partially obscured, and obscured quasars. Quasars are classified by the ratio νL ν (0.25 µm)/νL ν (7.8 µm) = UV/IR, assumed to measure obscuration of UV luminosity by the dust that …
Doppler Shift of the Quiet Region Measured by Meridional Scans with the EUV Imaging Spectrometer on board Hinode
Hara, H.; Kitagawa, N.; Yokoyama, T.
Spatially averaged (> 50") EUV spectral lines in the transition region of solar quiet regions are known to be redshifted. Because the mechanism underlying this phenomenon is unclear, we require additional physical information on the lower corona in order to limit the theoretical models. To acquire this information, we measured the Doppler shift…
AMiBA: Cluster Sunyaev-Zel’dovich Effect Observations with the Expanded 13-element Array
Koch, Patrick M.; Umetsu, Keiichi; Ho, Paul T. P. +35 more
The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is a co-planar interferometer array operating at a wavelength of 3 mm to measure the Sunyaev-Zel’dovich effect (SZE) of galaxy clusters at arcminute scales. The first phase of operation—with a compact 7-element array with 0.6 m antennas (AMiBA-7)—observed six clusters at angular s…
Statistically Determined Dispersion Relations of Magnetic Field Fluctuations in the Terrestrial Foreshock
Nakariakov, V. M.; Hnat, B.; O'Connell, D. +1 more
We obtain dispersion relations of magnetic field fluctuations for two crossings of the terrestrial foreshock by Cluster spacecraft. These crossings cover plasma conditions that differ significantly in their plasma β and in the density of the reflected ion beam, but not in the properties of the encountered ion population, both showing shell-like di…
Inflow Generated X-Ray Corona around Supermassive Black Holes and a Unified Model for X-Ray Emission
Cen, Renyue; Wang, Lile
Three-dimensional hydrodynamic simulations are performed, which cover the spatial domain from hundreds of Schwarzschild radii to 2 pc around the central supermassive black hole of mass {10}8{M}⊙ , with detailed radiative cooling processes. The existence of a significant amount of shock heated, high temperature (≥slant {10}