Search Publications
Sirius B Imaged in the Mid-infrared: No Evidence for a Remnant Planetary System
Close, Laird M.; Skemer, Andrew J.
Evidence is building that remnants of solar systems might orbit a large percentage of white dwarfs, as the polluted atmospheres of DAZ and DBZ white dwarfs indicate the very recent accretion of metal-rich material. Some of these polluted white dwarfs are found to have large mid-infrared excesses from close-in debris disks that are thought to be re…
Three-dimensional Structure of Microwave Sources from Solar Rotation Stereoscopy Versus Magnetic Extrapolations
Jing, Ju; Wang, Haimin; Fleishman, Gregory D. +5 more
We use rotation stereoscopy to estimate the height of a steady-state solar feature relative to the photosphere, based on its apparent motion in the image plane recorded over several days of observation. The stereoscopy algorithm is adapted to work with either one- or two-dimensional data (i.e., from images or from observations that record the proj…
Comparison of Seismic Signatures of Flares Obtained by SOHO/Michelson Doppler Imager and GONG Instruments
Zharkova, V. V.; Matthews, S. A.; Zharkov, S.
The first observations of seismic responses to solar flares were carried out using time-distance (TD) and holography techniques applied to SOHO/Michelson Doppler Imager (MDI) Dopplergrams obtained from space and unaffected by terrestrial atmospheric disturbances. However, the ground-based network GONG is potentially a very valuable source of sunqu…
A High-metallicity, High-velocity Cloud Along the Mrk 421 Sight Line: A Tracer of Complex M?
Shull, J. Michael; Danforth, Charles W.; Yao, Yangsen
We present a new measurement, 0.85-3.5 Z sun, of the metallicity of high-velocity cloud (HVC) Complex M by analyzing ultraviolet spectroscopic observations of the blazar Mrk 421 taken with the Cosmic Origins Spectrograph on the Hubble Space Telescope and the Far-Ultraviolet Spectroscopic Explorer. Although an HVC at V LSR = -…
Intracluster Medium of the Merging Cluster A3395
Singh, K. P.; Saikia, D. J.; Hunstead, R. W. +1 more
We present a detailed imaging and spectral analysis of the merging environment of the bimodal cluster A3395 using X-ray and radio observations. X-ray images of the cluster show five main constituents of diffuse emission: A3395 NE, A3395 SW, A3395 NW, A3395 W, and a filament connecting NE to W. X-ray surface brightness profiles of the cluster did n…
Dual Origin of Aerosols in Titan's Detached Haze Layer
Rodriguez, S.; West, R. A.; Brahic, A. +3 more
We have analyzed scattered light profiles from the Cassini Imaging Science Subsystem, taken at the limb and at several large phase angles. We also used results from an occultation observed by Ultraviolet Imaging Spectrograph in the ultraviolet. We found that particles responsible for the scattering in the detached haze have an effective radius aro…
A Light-curve Model of the Symbiotic Nova PU Vul (1979): A Very Quiet Explosion with Long-lasting Flat Peak
Cassatella, Angelo; Kato, Mariko; Hachisu, Izumi +1 more
We present a light-curve model of the symbiotic nova PU Vul (Nova Vulpeculae 1979) that shows a long-lasting flat peak with no spectral indication of wind mass loss before decline. Our quasi-evolution models consisting of a series of static solutions explain both the optical flat peak and ultraviolet (UV) light curve simultaneously. The white dwar…
Soft Time Lags in the X-Ray Emission of Mrk 1040
Dewangan, Gulab; Misra, Ranjeev; Tripathi, Shruti +1 more
Temporal analysis of X-ray binaries and active galactic nuclei (AGNs) have shown that hard X-rays react to variation of soft ones after a time delay. The opposite trend, or soft lag, has only been seen in a few rare quasi-periodic oscillations in X-ray binaries and recently for the AGN 1H 0707-495, on short timescales of ~103 s. Here, w…
Clustering Properties of Far-infrared Sources in Hi-GAL Science Demonstration Phase Fields
Testi, L.; Elia, D.; Schisano, E. +9 more
We use a minimum spanning tree (MST) algorithm to characterize the spatial distribution of Galactic far-IR sources and derive their clustering properties. We aim to reveal the spatial imprint of different types of star-forming processes, e.g., isolated spontaneous fragmentation of dense molecular clouds, or events of triggered star formation aroun…
The 2010 May Flaring Episode of Cygnus X-3 in Radio, X-rays, and γ-rays
Pottschmidt, Katja; Wilms, Jörn; Bower, Geoffrey C. +7 more
In 2009, Cygnus X-3 (Cyg X-3) became the first microquasar to be detected in the GeV γ-ray regime, via the satellites Fermi and AGILE. The addition of this new band to the observational toolbox holds promise for building a more detailed understanding of the relativistic jets of this and other systems. We present a rich data set of radio, hard and …