Search Publications
Energetic particle pressure in Saturn's magnetosphere measured with the Magnetospheric Imaging Instrument on Cassini
Krupp, N.; Dougherty, M. K.; Krimigis, S. M. +5 more
The Magnetospheric Imaging Instrument on board Cassini has been providing measurements of energetic ion intensities, energy spectra, and ion composition, combining the Charge Energy Mass Spectrometer over the range 3 to 236 keV/e, the Low Energy Magnetospheric Measurements System for ions in the range 0.024 to 18 MeV, and the Ion and Neutral Camer…
Observations and Nonlinear Force-Free Field Modeling of Active Region 10953
Golub, Leon; van Ballegooijen, Adriaan; Lites, Bruce W. +5 more
We present multiwavelength observations of a simple bipolar active region (NOAA 10953), which produced several small flares (mostly B class and one C8.5 class) and filament activations from April 30 to May 3 in 2007. We also explore nonlinear force-free field (NLFFF) modeling of this region prior to the C8.5 flare on May 2, using magnetograph data…
On the Extended Structure of the Phoenix Dwarf Galaxy
Aparicio, Antonio; Martínez-Delgado, David; Hidalgo, Sebastian L. +1 more
We present the star formation history (SFH) and its variations with galactocentric distance for the Local Group dwarf galaxy of Phoenix. They have been derived from a (F555W, F814W) color-magnitude diagram obtained from WFPC2@HST data, which reaches the oldest main-sequence turnoffs. The IAC-star and IAC-pop codes and the MinnIAC suite have been u…
X-Ray and Infrared Observations of Two Externally Polluted White Dwarfs
Zuckerman, B.; Muno, M. P.; Jura, M. +1 more
With XMM-Newton and the Spitzer Space Telescope, we obtain upper bounds to the X-ray fluxes from G29-38 and GD 362, and the 70 µm flux from G29-38. These data provide indirect evidence that G29-38 is accreting from a tidally disrupted asteroid: it is neither accreting large amounts of hydrogen and helium nor is its surrounding dusty disk bei…
A relativistically smeared spectrum in the neutron star X-ray binary 4U 1705-44: looking at the inner accretion disc with X-ray spectroscopy
Santangelo, A.; Robba, N. R.; Papitto, A. +9 more
Iron emission lines at 6.4-6.97 keV, identified with fluorescent Kα transitions, are among the strongest discrete features in the X-ray band. These are therefore one of the most powerful probes to infer the properties of the plasma in the innermost part of the accretion disc around a compact object. In this paper, we present a recent XMM-Newton ob…
Heating Diagnostics with MHD Waves
Erdélyi, R.; Taroyan, Y.
The heating of the solar atmosphere is a fundamental problem of modern solar and astrophysics. A review of the seismological aspects of magnetohydrodynamic (MHD) waves with an emphasis on standing longitudinal waves in the context of coronal heating is presented. Efforts made recently may be split into two categories: forward modelling and data in…
Designing future dark energy space missions. I. Building realistic galaxy spectro-photometric catalogs and their first applications
Kneib, J. -P.; Aussel, H.; Ilbert, O. +12 more
Context: Future dark energy space missions such as JDEM and EUCLID are being designed to survey the galaxy population to trace the geometry of the universe and the growth of structure, which both depend on the cosmological model. To reach the goal of high precision cosmology they need to evaluate the capabilities of different instrument designs ba…
Determination of masses of the central black holes in NGC 524 and 2549 using laser guide star adaptive optics
Krajnović, Davor; Cappellari, Michele; Davies, Roger L. +1 more
We present observations of early-type galaxies NGC 524 and 2549 with laser guide star adaptive optics (LGS AO) obtained at GEMINI North telescope using the Near-infrared Integral Field Spectrograph (NIFS) integral field unit (IFU) in the K band. The purpose of these observations is to determine high spatial resolution stellar kinematics within the…
Constraining the Spin-down of the Nearby Isolated Neutron Star RX J0806.4-4123, and Implications for the Population of Nearby Neutron Stars
van Kerkwijk, M. H.; Kaplan, D. L.
The nearby isolated neutron stars (INSs) are a group of seven relatively slowly rotating neutron stars that show thermal X-ray spectra, most with broad absorption features. They are interesting both because they may allow one to determine fundamental neutron-star properties by modeling their spectra, and because they appear to be a large fraction …
The physical properties of Lyα emitting galaxies: not just primeval galaxies?
Castellano, M.; Pentericci, L.; Santini, P. +4 more
Aims: We have analyzed a sample of Lyman break galaxies from z ~ 3.5 to z ~ 6 selected from the GOODS-S field as B, V, and i-dropouts, and with spectroscopic observations showing that they have the Lyα line in emission. Our main aim is to investigate their physical properties and their dependence on the emission line characteristic and to shed lig…