Search Publications
Unresolved Mixed Polarity Magnetic Fields at Flux Cancellation Site in Solar Photosphere at 0.''3 Spatial Resolution
Lites, Bruce W.; Kubo, Masahito; Chye Low, Boon
This is a follow-up investigation of a magnetic flux cancellation event at a polarity inversion line (PIL) on the Sun observed with the spectropolarimeter on board Hinode. Anomalous circular polarization (Stokes V) profiles are observed in the photosphere along the PIL at the cancellation sites. Kubo et al. previously reported that the theoretical…
MHD and kinetic analysis of flow bursts in the Earth's plasma sheet
Dandouras, I.; Reme, H.; Cao, JinBin +6 more
In an attempt to study the flow bursts in the Earth's plasma sheet we select an event that took place on August 7, 2004 in the expansion phase of a substorm, using data from the geomagnetic index, solar wind data, plasma and magnetic field observations from C1 Cluster satellite (the Cluster mission has 4 satellites) and from Double Star TC-1 satel…
Monitoring atmospheric dust spring activity at high southern latitudes on Mars using OMEGA
Douté, S.
This paper presents a monitoring of the atmospheric dust in the south polar region during spring of Martian year 27. Our goal is to contribute to identifying the regions where the dust concentration in the atmosphere shows specific temporal patterns, for instance high, variable, and on the rise due to lifting or transport mechanisms. This identifi…
The Black Hole Mass and the Stellar Ring in NGC 3706
Gebhardt, Karl; Kormendy, John; Lauer, Tod R. +4 more
We determine the mass of the nuclear black hole (M) in NGC 3706, an early-type galaxy with a central surface brightness minimum arising from an apparent stellar ring, which is misaligned with respect to the galaxy's major axis at larger radii. We fit new HST/STIS and archival data with axisymmetric orbit models to determine M, mass-to-light ratio …
Absorption at the dust sublimation radius and the dichotomy between X-ray and optical classification in the Seyfert galaxy H0557-385
Bianchi, S.; Guainazzi, M.; Ballo, L. +7 more
In this work, the analysis of multi-epoch (1995-2010) X-ray observations of the Seyfert 1 galaxy H0557-385 is presented. The wealth of data presented in this analysis show that the source exhibits dramatic spectral variability, from a typical unabsorbed Seyfert 1 type spectrum to a Compton-thin absorbed state, on time-scales of ∼5 yr. This extreme…
The giant H ii region NGC 588 as a benchmark for 2D photoionisation models
Morisset, C.; Monreal-Ibero, A.; Relaño, M. +3 more
Aims: We use optical integral field spectroscopy and 8 µm and 24 µm mid-IR observations of the giant H ii region NGC 588 in the disc of M33 as input and constraints for two-dimensional tailor-made photoionisation models under different geometrical approaches. We do this to explore the spatial distribution of gas and dust in the in…
High proper motion X-ray binaries from the Yale Southern Proper Motion Survey
Maccarone, Thomas J.; Casetti-Dinescu, Dana I.; Girard, Terrence M.
We discuss the results of cross-correlating catalogues of bright X-ray binaries with the Yale Southern Proper Motion Catalog (version 4.0). Several objects already known to have large proper motions from Hipparcos are recovered. Two additional objects are found which show substantial proper motions, both of which are unusual in their X-ray propert…
The structure of Abell 1351: a bimodal galaxy cluster with peculiar diffuse radio emission
Rossetti, M.; De Grandi, S.; Boschin, W. +2 more
We aim to review the internal structure and dynamics of the Abell 1351 cluster, shown to host a radio halo with a quite irregular shape. Our analysis is based on radial velocity data for 135 galaxies obtained at the Telescopio Nazionale Galileo. We combine galaxy velocities and positions to select 95 cluster galaxy members and analyse the internal…
Impact of thermal diffusion and other abundance anomalies on cosmological uses of galaxy clusters
Sazonov, S.; Gilfanov, M.; Medvedev, P. +1 more
Depending on the topology of the magnetic field and characteristics of turbulent motions, diffusion can significantly affect the distribution of elements, in particular helium, in the intracluster medium (ICM). As has been noted previously, an incorrect assumption about the helium abundance will lead to an error in the iron abundance determined fr…
Modeling X-Ray Emission around Galaxies
Bregman, Joel N.; Anderson, Michael E.
Extended X-ray emission can be studied by spatial surface brightness measurements or by spectral analysis, but the two methods can disagree at low intensity levels. Here we present an improved method for spatial analysis that can be extended to include spectral information simultaneously. We construct a model for the entire image in a given energy…