Search Publications
Spectroscopic Confirmation of Multiple Red Galaxy-Galaxy Mergers in MS 1054-03 (z = 0.83)1,
Franx, Marijn; Kelson, Daniel D.; Illingworth, Garth D. +3 more
We present follow-up spectroscopy of the galaxy cluster MS 1054-03 (z=0.83) confirming that at least six of the nine merging galaxy pairs identified by van Dokkum et al. in 1999 are indeed bound systems: they have projected separations of Rs<10 h-1 kpc and relative line-of-sight velocities of Δv<165 km s-1. F…
Highly Ionized Iron Absorption Lines from Outflowing Gas in the X-Ray Spectrum of NGC 1365
Zezas, A.; Bianchi, S.; Elvis, M. +4 more
We present the discovery of four absorption lines in the X-ray spectrum of the Seyfert galaxy NGC 1365, at energies between 6.7 and 8.3 keV. The lines are detected with high statistical confidence (from >20 σ for the strongest to ~4 σ for the weakest) in two XMM-Newton observations 60 ks long. We also detect the same lines, with a lower signal-…
The Binarity of η Carinae Revealed from Photoionization Modeling of the Spectral Variability of the Weigelt Blobs B and D
Bruhweiler, F.; Gull, T.; Verner, E.
We focus on two Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) spectra of the Weigelt blobs B and D, extending from 1640 to 10400 Å, one recorded during the 1998 minimum (1998 March) and the other recorded in 1999 February, early in the following broad maximum. The spatially resolved spectra suggest two distinct ionization …
Measuring the Cosmic Evolution of Dark Energy with Baryonic Oscillations in the Galaxy Power Spectrum
Glazebrook, Karl; Blake, Chris
We use Monte Carlo techniques to simulate the ability of future large high-redshift galaxy surveys to measure the temporal evolution of the dark energy equation of state w(z), using the baryonic acoustic oscillations in the clustering power spectrum as a ``standard ruler.'' Our analysis utilizes only the oscillatory component of the power spectrum…
X-Ray/Ultraviolet Campaign on the Mrk 279 AGN Outflow: Constraining Inhomogeneous Absorber Models
Kriss, Gerard A.; Kaastra, Jelle; Korista, Kirk T. +3 more
We investigate the applicability of inhomogeneous absorber models in the formation of active galactic nucleus outflow absorption troughs. The models we explore are limited to monotonic gradients of absorbing column densities in front of a finite emission source. Our main finding is that simple power-law and Gaussian distributions are hard-pressed …
Far-Ultraviolet Spectroscopy of Magnetic Cataclysmic Variables
Szkody, Paula; Sion, Edward M.; Gänsicke, Boris T. +4 more
We have obtained Hubble Space Telescope (HST) STIS data for a total of 11 polars as part of a program aimed at compiling a homogeneous database of high-quality far-ultraviolet (FUV) spectra for a large number of cataclysmic variables (CVs). Of the 11 polars, eight were found in a state of low accretion activity (V347 Pav, VV Pup, V834 Cen, BL Hyi,…
Turbulence-driven Solar Wind Heating and Energization of Pickup Protons in the Outer Heliosphere
Isenberg, Philip A.
We improve and extend the ``dominant turbulence'' model of Isenberg et al., which describes the turbulent heating of the distant solar wind by the dissipation of wave energy generated by the isotropization of interstellar pickup protons. We first modify some of the detailed expressions in Isenberg et al. to fully incorporate the effects of wave di…
Local Correlation Tracking and the Magnetic Induction Equation
Schuck, P. W.
Recently, local correlation tracking has been applied to magnetograms to estimate photospheric velocities. This Letter demonstrates that local correlation tracking is inconsistent with the magnetic induction equation, which governs the temporal evolution of the photospheric magnetograms. A modified formulation, consistent with the magnetic inducti…
The Evolution of Coronal Mass Ejection Density Structures
Gombosi, T. I.; Lugaz, N.; Manchester, W. B., IV
We present a discussion of the time evolution of the mass and energy of a model coronal mass ejection (CME), analyzing both synthetic coronograph images and three-dimensional data of the numerical ideal magnetohydrodynamics (MHD) simulation. Our global steady state coronal model possesses high-latitude coronal holes and a helmet streamer structure…
Decomposition of the Visible and Dark Matter in the Einstein Ring 0047-2808 by Semilinear Inversion
Dye, S.; Warren, S. J.
We measure the mass density profile of the lens galaxy in the Einstein ring system 0047-2808 using our semilinear inversion method developed in an earlier paper. By introducing an adaptively gridded source plane, we are able to eliminate the need for regularization of the inversion. This removes the problem of a poorly defined number of degrees of…