Search Publications
An XMM-Newton Study of the Bright, Nearby Supernova Remnant G296.1-0.5
Gaensler, B. M.; Hughes, J. P.; Castro, D. +2 more
We present a detailed study of the supernova remnant (SNR) G296.1-0.5, performed using observations with the European Photon Imaging Camera (EPIC) and Reflection Grating Spectrometer instruments of the XMM-Newton satellite. G296.1-0.5 is a bright remnant that displays an incomplete multiple-shell morphology in both its radio and X-ray images. We u…
The Displaced Dusty Interstellar Medium of NGC 3077: Tidal Stripping in the M 81 Triplet
Helou, G.; Roussel, H.; Murphy, E. J. +32 more
We present the detection of extended (~30 kpc2) dust emission in the tidal H I arm near NGC 3077 (member of the M 81 triplet) using SPIRE on board Herschel. Dust emission in the tidal arm is typically detected where the H I column densities are >1021 cm-2. The SPIRE band ratios show that the dust in the tidal ar…
On the apparent absence of broad iron lines in Seyfert galaxies
Nandra, K.; Bhayani, S.
We present an analysis of XMM-Newton observations of 11 Seyfert galaxies that appear to be missing a broad iron Kα line. These objects represent a challenge to the established paradigm for active galactic nuclei, where a relatively cold accretion disc feeds the central black hole. In that paradigm, X-ray illumination of the accretion disc should l…
Superpixel segmentation for analysis of hyperspectral data sets, with application to Compact Reconnaissance Imaging Spectrometer for Mars data, Moon Mineralogy Mapper data, and Ariadnes Chaos, Mars
Gilmore, Martha S.; Thompson, David R.; Anderson, Laura J. +3 more
We present a semiautomated method to extract spectral end-members from hyperspectral images. This method employs superpixels, which are spectrally homogeneous regions of spatially contiguous pixels. The superpixel segmentation is combined with an unsupervised end-member extraction algorithm. Superpixel segmentation can complement per pixel classif…
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…
The XMM-Newton survey of the Small Magellanic Cloud: XMMU J005011.2-730026 = SXP 214, a Be/X-ray binary pulsar
Pietsch, W.; Haberl, F.; Tiengo, A. +10 more
In the course of the XMM-Newton survey of the Small Magellanic Cloud, a region to the east of the emission nebula N19 was observed in 2009 November. To search for new candidates for high-mass X-ray binaries, the EPIC-pn and EPIC-MOS data of the detected point sources were investigated and their spectral and temporal characteristics identified. A n…
Iron abundance in the prototype PG 1159 star, GW Vir pulsator PG 1159 - 035, and related objects
Rauch, T.; Werner, K.; Kruk, J. W. +1 more
We performed an iron abundance determination of the hot, hydrogen deficient post-AGB star PG 1159 - 035, which is the prototype of the PG 1159 spectral class and the GW Vir pulsators, and of two related objects (PG 1520 + 525, PG 1144 + 005), based on the first detection of Fe viii lines in stellar photospheres. In another PG 1159 star, PG 1424 + …
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…
Spatiotemporal features of the auroral acceleration region as observed by Cluster
Karlsson, Tomas; Fazakerley, Andrew; Nilsson, Hans +5 more
A pair of negative electric potential structures associated with inverted-V aurora is investigated using electric and magnetic field, ion and electron data from the Cluster spacecraft, crossing the auroral acceleration region (AAR) at different altitudes above the Northern hemisphere midnight auroral oval. The spatial and temporal development of t…
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…