Search Publications
Quantifying the contamination by old main-sequence stars in young moving groups: the case of the Local Association
Montes, D.; Micela, G.; López-Santiago, J.
Context: The associations and moving groups of young stars are excellent laboratories for investigating stellar formation in the solar neighborhood. Previous results have confirmed that a non-negligible fraction of old main-sequence stars is present in the lists of possible members of young stellar kinematic groups. A detailed study of the propert…
Dark Matter in the Galaxy Cluster CL J1226+3332 at z = 0.89
Tyson, J. Anthony; Jee, M. James
We present a weak-lensing analysis of the galaxy cluster CL J1226+3332 at z sime 0.89 using Hubble Space Telescope Advanced Camera for Surveys images. The cluster is the hottest (>10 keV), most X-ray luminous system at z > 0.6 known to date. The relaxed X-ray morphology, as well as its high temperature, is unusual at such a high redshift. Ou…
A model of the TeV flare of Cygnus X-1: electron acceleration and extended pair cascades
Bednarek, W.; Zdziarski, Andrzej A.; Malzac, Julien
We consider theoretical models of emission of TeV photons by Cyg X-1 during a flare discovered by the Major Atmospheric Gamma Imaging Cherenkov Telescope (MAGIC) detector. We study acceleration of electrons to energies sufficient for TeV emission, and find the emission site is allowed to be close to the black hole. We then consider pair absorption…
New EUV Fe IX Emission Line Identifications from Hinode/EIS
Young, P. R.
Four Fe IX transitions in the wavelength range 188-198 Å are identified for the first time in spectra from the EUV Imaging Spectrometer on board the Hinode satellite. In particular the emission line at 197.86 Å is unblended and close to the peak of the EIS sensitivity curve, making it a valuable diagnostic of plasma at around 800,000 K — a critica…
The effect of spacecraft radiation sources on electron moments from the Cassini CAPS electron spectrometer
Coates, Andrew J.; Arridge, Christopher S.; Jones, Geraint H. +5 more
Data from the Cassini plasma spectrometer (CAPS) electron spectrometer (ELS) have been found to be contaminated with an energy-independent background count rate which has been associated with radiation sources on Cassini. In this paper we describe this background radiation and quantitatively assess its impact on numerically integrated electron mom…
Suzaku Observations of Near-Relativistic Outflows in the BAL Quasar APM 08279+5255
Brandt, W. N.; Chartas, G.; Saez, C.
We present results from three Suzaku observations of the z = 3.91 gravitationally lensed broad absorption line quasar APM 08279+5255. We detect strong and broad absorption at rest-frame energies of lsim2 keV (low energy) and 7-12 keV (high energy). The detection of these features confirms the results of previous long-exposure (80-90 ks) Chandra an…
Recent orbital evolution and the internal structures of Enceladus and Dione
Zhang, Ke; Nimmo, Francis
We study the orbital behavior of Saturn's satellites Enceladus and Dione during their passage through the 2:1 mean-motion resonances to constrain their interior structures, parameterized by the quantity k2/Q (assumed constant). Enceladus' evolution after escape from the second-order e-Enceladus e-Dione resonance requires that (k2
Integral field optical spectroscopy of a representative sample of ULIRGs. II. Two-dimensional kpc-scale extinction structure
Colina, L.; Arribas, S.; García-Marín, M.
Context: Ultraluminous infrared galaxies are merging systems characterized for containing large amounts of dust and emitting the bulk of their energy in the infrared. Dust affects several of the observed properties derived from optical and near-IR rest-frame data, such as the stellar morphology and the ionized gas distribution. Systematic analysis…
Plasma wake of Tethys: Hybrid simulations versus Cassini MAG data
Dougherty, M. K.; Saur, J.; Neubauer, F. M. +2 more
The interaction between Saturn's fifth largest satellite, Tethys, and the corotating plasma of the inner magnetosphere has been studied with a three-dimensional hybrid simulation. Since Tethys possesses neither an intrinsic magnetic field nor a substantial ionosphere, the moon's surface is directly exposed to the impinging plasma. This leads to th…
90 GHz and 150 GHz Observations of the Orion M42 Region. A Submillimeter to Radio Analysis
Ade, P. A. R.; Martin, P. G.; Sievers, A. +13 more
We have used the new 90 GHz MUSTANG camera on the Robert C. Byrd Green Bank Telescope (GBT) to map the bright Huygens region of the star-forming region M42 with a resolution of 9'' and a sensitivity of 2.8 mJy beam-1. Ninety GHz is an interesting transition frequency, as MUSTANG detects both the free-free emission characteristic of the …