Search Publications
Extreme-ultraviolet and X-Ray Observations of Comet Lovejoy (C/2011 W3) in the Lower Corona
Raymond, John C.; Saar, Steven H.; Ko, Yuan-Kuen +2 more
We present an analysis of extreme-ultraviolet and soft X-ray emission detected toward Comet Lovejoy (C/2011 W3) during its post-perihelion traverse of the solar corona on 2011 December 16. Observations were recorded by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory and the X-Ray Telescope (XRT) aboard Hinode. A single…
Emission Height and Temperature Distribution of White-light Emission Observed by Hinode/SOT from the 2012 January 27 X-class Solar Flare
Masuda, Satoshi; Ohno, Masanori; Shimizu, Toshifumi +2 more
White-light emissions were observed from an X1.7 class solar flare on 2012 January 27, using three continuum bands (red, green, and blue) of the Solar Optical Telescope on board the Hinode satellite. This event occurred near the solar limb, and so differences in the locations of the various emissions are consistent with differences in heights abov…
Evolution of the Stratospheric Temperature and Chemical Composition over One Titanian Year
Coustenis, Athena; Teanby, N. A.; Flasar, F. M. +11 more
Since the Voyager 1 (V1) flyby in 1980, Titan's exploration from space and the ground has been ongoing for more than a full revolution of Saturn around the Sun (one Titanian year or 29.5 Earth years had elapsed in 2010 May). In this study, we search for temporal variations affecting Titan's atmospheric thermal and chemical structure within that ye…
De-excitation Nuclear Gamma-Ray Line Emission from Low-energy Cosmic Rays in the Inner Galaxy
Strong, A. W.; Kiener, J.; Tatischeff, V. +1 more
Recent observations of high ionization rates of molecular hydrogen in diffuse interstellar clouds point to a distinct low-energy cosmic-ray component. Supposing that this component is made of nuclei, two models for the origin of such particles are explored and low-energy cosmic-ray spectra are calculated, which, added to the standard cosmic-ray sp…
Rotation Rates of Coronal Holes and their Probable Anchoring Depths
Hegde, M.; Hiremath, K. M.
From 2001-2008, we use full-disk, SOHO/EIT 195 Å calibrated images to determine latitudinal and day-to-day variations of the rotation rates of coronal holes (CHs). We estimate the weighted average of heliographic coordinates such as latitude and longitude from the central meridian on the observed solar disk. For different latitude zones between 40…
XMM-Newton Monitoring of the Close Pre-main-sequence Binary AK Sco. Evidence of Tide-driven Filling of the Inner Gap in the Circumbinary Disk
Gómez de Castro, Ana I.; Talavera, Antonio; Bisikalo, D. +2 more
AK Sco stands out among pre-main-sequence binaries because of its prominent ultraviolet excess, the high eccentricity of its orbit, and the strong tides driven by it. AK Sco consists of two F5-type stars that get as close as 11 R * at periastron passage. The presence of a dense (ne ~ 1011 cm-3) extended …
Constraints on Porosity and Mass Loss in O-star Winds from the Modeling of X-Ray Emission Line Profile Shapes
Leutenegger, Maurice A.; Cohen, David H.; Sundqvist, Jon O. +1 more
We fit X-ray emission line profiles in high resolution XMM-Newton and Chandra grating spectra of the early O supergiant ζ Pup with models that include the effects of porosity in the stellar wind. We explore the effects of porosity due to both spherical and flattened clumps. We find that porosity models with flattened clumps oriented parallel to th…
A Survey of Infrared Supernova Remnants in the Large Magellanic Cloud
Onaka, Takashi; Seok, Ji Yeon; Koo, Bon-Chul
We present a comprehensive infrared study of supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using near- to mid-infrared images taken by Infrared Array Camera (IRAC; 3.6, 4.5, 5.8, and 8 µm) and Multiband Imaging Photometer (MIPS; 24 and 70 µm) onboard the Spitzer Space Telescope. Among the 47 bona fide LMC SNRs, 29 were …
Imaging the Disk and Jet of the Classical T Tauri Star AA Tau
Russell, Ray W.; Sitko, Michael L.; Grady, Carol A. +4 more
Previous studies of the classical T Tauri star AA Tau have interpreted the UX-Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use Hubble Space Telescope…
Sloshing Cold Fronts in Galaxy Groups and their Perturbing Disk Galaxies: An X-Ray, Optical, and Radio Case Study
Humphrey, Philip J.; Buote, David A.; Brighenti, Fabrizio +10 more
We present a combined X-ray, optical, and radio analysis of the galaxy group IC 1860 using the currently available Chandra and XMM data, multi-object spectroscopy data from the literature, and Giant Metrewave Radio Telescope (GMRT) data. The Chandra and XMM imaging and spectroscopy reveal two surface brightness discontinuities at 45 and 76 kpc sho…