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The Evolution of the Optical and Near-Infrared Galaxy Luminosity Functions and Luminosity Densities to z~2
Dickinson, Mark; Ferguson, Henry C.; Giavalisco, Mauro +4 more
Using Hubble Space Telescope and ground-based U through Ks photometry from the Great Observatories Origins Deep Survey, we measure the evolution of the luminosity function and luminosity density in the rest-frame optical (U, B, and R) to z~2, bridging the poorly explored ``redshift desert'' between z~1 and ~2. We also use deep near-infr…
Solar source of the largest geomagnetic storm of cycle 23
Howard, R. A.; Gopalswamy, N.; Michalek, G. +3 more
The largest geomagnetic storm of solar cycle 23 occurred on 2003 November 20 with a Dst index of -472 nT, due to a coronal mass ejection (CME) from active region 0501. The CME near the Sun had a sky-plane speed of ~1660 km/s, but the associated magnetic cloud (MC) arrived with a speed of only 730 km/s. The MC at 1 AU (ACE Observations) had a high …
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…
A soft solid surface on Titan as revealed by the Huygens Surface Science Package
Banaszkiewicz, Marek; Zarnecki, John C.; Lorenz, Ralph D. +23 more
The surface of Saturn's largest satellite-Titan-is largely obscured by an optically thick atmospheric haze, and so its nature has been the subject of considerable speculation and discussion. The Huygens probe entered Titan's atmosphere on 14 January 2005 and descended to the surface using a parachute system. Here we report measurements made just a…
Density-potential pairs for spherical stellar systems with Sérsic light profiles and (optional) power-law cores
Graham, Alister W.; Terzić, Balša
Popular models for describing the luminosity-density profiles of dynamically hot stellar systems (e.g. Jaffe, Hernquist, Dehnen) were constructed with the desire to match the deprojected form of an R1/4 light profile. Real galaxies, however, are now known to have a range of different light-profile shapes that scale with mass. Consequent…
A model of the Alfvén speed in the solar corona
Mann, G.; Warmuth, A.
We present an analytic model of the Alfvén speed vA in the solar corona. The coronal magnetic field is modeled by a radial component representing the global field and by a dipole representing an active region. The free parameters of the model are constrained by actual observations of solar magnetic fields and coronal electron densities.…
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 …