Search Publications
Magnetic Flux Ropes in the Solar Photosphere: The Vector Magnetic Field under Active Region Filaments
Lites, B. W.
This study is an observational search for evidence of prominence-associated magnetic flux ropes at the photospheric level in plage regions away from sunspots. Although there are a few cases of supposed flux rope geometry in the photosphere of complex sunspot regions (notably ``δ sunspots''), such cases appear to be fairly rare and therefore do not…
Physics of accretion in the millisecond pulsar XTE J1751-305
Gierliński, Marek; Poutanen, Juri
We have undertaken an extensive study of X-ray data from the accreting millisecond pulsar XTE J1751-305 observed by RXTE and XMM-Newton during its 2002 outburst. In all aspects this source is similar to the prototypical millisecond pulsar SAX J1808.4-3658, except for the higher peak luminosity of 13 per cent of Eddington, and the optical depth of …
Reddening, Absorption, and Decline Rate Corrections for a Complete Sample of Type Ia Supernovae Leading to a Fully Corrected Hubble Diagram to v < 30,000 km s-1
Saha, A.; Tammann, G. A.; Reindl, B. +1 more
Photometric (BVI) and redshift data corrected for streaming motions are compiled for 111 ``Branch-normal,'' four 1991T-like, seven 1991bg-like, and two unusual supernovae of Type Ia (SNe Ia). Color excesses E(B-V)host of normal SNe Ia, due to the absorption of the host galaxy, are derived by three independent methods, giving excellent a…
An Infrared Coronagraphic Survey for Substellar Companions
Weinberger, Alycia J.; Schneider, Glenn; Hines, Dean C. +10 more
We have used the F160W filter (1.4-1.8 µm) and the coronagraph on the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope to survey 45 single stars with a median age of 0.15 Gyr, an average distance of 30 pc, and an average H magnitude of 7 mag. For the median age we were capable of detecting a 30MJ…
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…