Search Publications
Rotational modulation and local time dependence of Saturn's infrared H3+ auroral intensity
Brown, R. H.; Baines, K. H.; Lamy, L. +10 more
Planetary auroral emissions reveal the configuration of magnetospheric field-aligned current systems. In this study, Cassini Visual and Infrared Mapping Spectrometer (VIMS) observations of Saturn's pre-equinox infrared H3+ aurorae were analysed to show (a) rotational modulation of the auroral intensity in both hemispheres and…
Accretion flow diagnostics with X-ray spectral timing: the hard state of SWIFT J1753.5-0127
Maccarone, T. J.; Uttley, P.; Cassatella, P.
Recent XMM-Newton studies of X-ray variability in the hard states of black hole X-ray binaries (BHXRBs) indicate that the variability is generated in the 'standard' optically thick accretion disc that is responsible for the multi-colour blackbody emission. The variability originates in the disc as mass-accretion fluctuations and propagates through…
A Three-dimensional View of the Remnant of Nova Persei 1901 (GK Per)
Corradi, R. L. M.; Santander-García, M.; Rodríguez-Gil, P. +4 more
We present a kinematical study of the optical ejecta of GK Per. It is based on proper-motion measurements of 282 knots from ~20 images spanning 25 years. Doppler shifts are also computed for 217 knots. The combination of proper motions and radial velocities allows a unique three-dimensional view of the ejecta to be obtained. The main results are a…
Spatially resolved X-ray spectroscopy and modeling of the nonthermal emission of the pulsar wind nebula in G0.9+0.1
Stegmann, C.; Eger, P.; Schöck, F. M. +3 more
Aims: We performed a spatially resolved spectral X-ray study of the pulsar wind nebula (PWN) in the supernova remnant G0.9+0.1. Furthermore, we modeled its nonthermal emission in the X-ray and very high-energy (VHE, E > 100 GeV) γ-ray regime.
Methods: Using Chandra ACIS-S3 data, we investigated the east-west dependence of the spectral…
Statistics and implications of substructure detected in a representative sample of X-ray clusters
Böhringer, H.; Smith, G. P.; Chon, G.
We present a morphological study of 35 X-ray luminous galaxy clusters at 0.15 < z < 0.3, selected in a similar manner to the Local Cluster Substructure Survey (LoCuSS), for which deep XMM-Newton observations are available. We characterise the structure of the X-ray surface brightness distribution of each cluster by measuring both their power…
DRAFTS: A Deep, Rapid Archival Flare Transient Search in the Galactic Bulge
Hawley, Suzanne L.; Osten, Rachel A.; Sahu, Kailash +1 more
We utilize the Sagittarius Window Eclipsing Extrasolar Planet Search Hubble Space Telescope/Advanced Camera for Surveys data set for a Deep Rapid Archival Flare Transient Search to constrain the flare rate toward the older stellar population in the Galactic bulge. During seven days of monitoring 229,293 stars brighter than V = 29.5, we find eviden…
Double Horizontal Branches in NGC 6440 and NGC 6569 Unveiled by the VVV Survey
Minniti, Dante; Geisler, Doug; Moni Bidin, Christian +5 more
We report the discovery of a peculiar horizontal branch (HB) in NGC 6440 and NGC 6569, two massive and metal-rich Galactic globular clusters (GGCs) located in the Galactic bulge, within 4 kpc from the Galactic center. In both clusters, two distinct clumps are detected at the level of the cluster HB, separated by only ~0.1 mag in the K s…
Saturn’s high degree magnetic moments: Evidence for a unique planetary dynamo
Cao, Hao; Dougherty, Michele K.; Russell, Christopher T. +2 more
Saturn’s intrinsic magnetic field has long been known to be highly axisymmetric. None of the existing field models goes beyond spherical harmonic degree 3. In this paper, we assume that the axisymmetry extends to higher degrees. This allows us to derive the degree 4 and 5 axial moments by searching their parameter space based on the Cassini Saturn…
Estimation of the galactic spiral pattern speed from Cepheids
Bobylev, V. V.; Bajkova, A. T.
To study the peculiarities of the Galactic spiral density wave, we have analyzed the space velocities of Galactic Cepheids with propermotions from the Hipparcos catalog and line-of-sight velocities from various sources. First, based on the entire sample of 185 stars and taking R 0 = 8 kpc, we have found the components of the peculiar so…
Seasonal variations in Saturn's plasma between the main rings and Enceladus
Wilson, R. J.; Johnson, R. E.; Elrod, M. K. +1 more
With the discovery by the Cassini spacecraft of an oxygen atmosphere over Saturn's main rings, and a strong source of water products from the plumes of Saturn's moon Enceladus, our picture of the physics of Saturn's magnetosphere from the main rings to inside the orbit of Enceladus has changed dramatically. This region contains oxygen ions from th…