Search Publications
Pulse-amplitude-resolved spectroscopy of bright accreting pulsars: indication of two accretion regimes
Klochkov, D.; Santangelo, A.; Ferrigno, C. +2 more
Context. In addition to coherent pulsation, many accreting neutron stars exhibit flaring activity and strong aperiodic variability on time scales comparable to or shorter than their pulsation period. This behavior shows that the accretion flow in the vicinity of the accretor must be highly non-stationary. Observational study of this phenomenon is …
AzTEC/ASTE 1.1-mm survey of the AKARI Deep Field South: source catalogue and number counts
Yun, M. S.; Iono, D.; Khan, S. +20 more
We present results of a 1.1-mm deep survey of the AKARI Deep Field South (ADF-S) with AzTEC mounted on the Atacama Submillimetre Telescope Experiment (ASTE). We obtained a map of 0.25-deg2 area with an rms noise level of 0.32-0.71 mJy. This is one of the deepest and widest maps thus far at millimetre and submillimetre wavelengths. We un…
Antiparallel and component reconnection at the dayside magnetopause
Fuselier, S. A.; Trattner, K. J.; Petrinec, S. M.
Two types of reconnection occur at the Earth's magnetopause: component and antiparallel reconnection. Recently, an empirical model was developed that purportedly determines under what solar wind conditions one or the other type of reconnection is dominant. This empirical model is tested using observations at the magnetopause from the Cluster space…
Observational Constraints on Red and Blue Helium Burning Sequences
McQuinn, Kristen B. W.; Dolphin, Andrew E.; Skillman, Evan D. +4 more
We derive the optical luminosity, colors, and ratios of the blue and red helium burning (HeB) stellar populations from archival Hubble Space Telescope observations of nineteen starburst dwarf galaxies and compare them with theoretical isochrones from Padova stellar evolution models across metallicities from Z = 0.001 to 0.009. We find that the obs…
Discovery of a massive X-ray luminous galaxy cluster at z = 1.579
Böhringer, H.; Rosati, P.; Nonino, M. +11 more
We report on the discovery of a very distant galaxy cluster serendipitously detected in the archive of the XMM-Newton mission, within the scope of the XMM-Newton Distant Cluster Project (XDCP). XMMUJ0044.0-2033 was detected at a high significance level (5σ) as a compact, but significantly extended source in the X-ray data, with a soft-band flux f(…
Global properties of 'ordinary' early-type galaxies: photometry and spectroscopy of stars and globular clusters in NGC 4494
Spitler, Lee R.; Forbes, Duncan A.; Romanowsky, Aaron J. +7 more
We present a comprehensive analysis of the spatial, kinematic and chemical properties of stars and globular clusters (GCs) in the `ordinary' elliptical galaxy NGC 4494 using data from the Keck and Subaru telescopes. We derive galaxy surface brightness and colour profiles out to large galactocentric radii. We compare the latter to metallicities der…
Toward Precision LSST Weak-Lensing Measurement. I. Impacts of Atmospheric Turbulence and Optical Aberration
Tyson, J. Anthony; Jee, M. James
The weak-lensing science of the Large Synoptic Survey Telescope (LSST) project drives the need to carefully model and separate the instrumental artifacts from the intrinsic shear signal caused by gravitational lensing. The dominant source of the systematics for all ground-based telescopes is the spatial correlation of the point-spread function (PS…
The close circumstellar environment of Betelgeuse. II. Diffraction-limited spectro-imaging from 7.76 to 19.50 µm with VLT/VISIR
Kervella, P.; Chiavassa, A.; Verhoelst, T. +4 more
Context. Mass-loss occurring in red supergiants (RSGs) is a major contributor to the enrichment of the interstellar medium in dust and molecules. The physical mechanism of this mass loss is however relatively poorly known. Betelgeuse is the nearest RSG, and as such a prime object for high angular resolution observations of its surface (by interfer…
Dipolarization fronts in the magnetotail plasma sheet
Russell, C. T.; Glassmeier, K. -H.; Nakamura, R. +12 more
We present a THEMIS study of a dipolarization front associated with a bursty bulk flow (BBF) that was observed in the central plasma sheet sequentially at X=-20.1, -16.7, and -11.0 RE. Simultaneously, the THEMIS ground network observed the formation of a north-south auroral form and intensification of westward auroral zone currents. Tim…
New limb-darkening coefficients and synthetic photometry for model-atmosphere grids at Galactic, LMC and SMC abundances
Howarth, Ian D.
New grids of ATLAS9 models have been calculated using revised convection parameters and updated opacity-distribution functions (ODFs), for chemical compositions intended to be representative of solar, [M/H] =+0.3, +0.5, Large Magellanic Cloud and Small Magellanic Cloud abundances. The grids cover Teff= 3.5-50 kK, from log g= 5.0 to the …