Search Publications
XMM-Newton Observations of Red AGNs
Wilkes, B. J.; Hines, D. C.; Smith, P. S. +5 more
XMM-Newton spectra of five red 2MASS active galactic nuclei (AGNs), selected from a sample observed by Chandra to be relatively X-ray bright and to cover a range of hardness ratios, confirm the presence of substantial absorbing material in three sources with optical classifications ranging from type 1 to type 2. A flat (hard) power-law continuum i…
Emission-Line Spectroscopy of Damped Lyα Systems: The Case of SBS 1543+593/HS 1543+5921
Turnshek, David A.; Hopkins, Andrew M.; Miller, Christopher J. +4 more
We report HST/STIS spectroscopy and Gemini/GMOS-N imaging of the Damped Lyα (DLA) system toward HS 1543+5921 caused by the host star-forming galaxy (SFG) SBS 1543+593. The Gemini image shows new morphological details of this well-resolved DLA galaxy. In combination with previous optical spectra, the new UV spectra enable us to compare, for the fir…
16 µm Imaging around the Hubble Deep Field-North with the Spitzer IRS
Chary, R.; Armus, L.; Charmandaris, V. +3 more
We present a pilot study of 16 µm imaging within the GOODS northern field. Observations were obtained using the ``peak-up'' imaging capability of the Spitzer IRS. We survey 35 arcmin2 to an average 3 σ depth of 0.075 mJy and detect 149 sources. The survey partially overlaps the area imaged at 15 µm by the ISO, and we demonst…
Recovering Solar Toroidal Field Dynamics from Sunspot Location Patterns
Norton, Aimee A.; Gilman, Peter A.
We analyze both Kitt Peak magnetogram data and MDI continuum intensity sunspot data to search for the following solar toroidal band properties: width in latitude and the existence of a tipping instability (longitudinal m=1 mode) for any time during the solar cycle. In order to determine the extent to which we can recover the toroidal field dynamic…
Solar Wind Outflow in Polar Plumes from 1.05 to 2.4 Rsolar
Llebaria, A.; Abbo, L.; Antonucci, E. +2 more
An earlier publication (Paper I), which measured the outflow velocity in solar plumes out to 1.35 Rsolar using the Doppler dimming technique, has here been extended out to 2.4 Rsolar by including observations from SOHO UVCS. It is shown that plume outflow velocities, greater than interplumes at lower heights, have lower accel…
X-Ray Emission and Optical Polarization of V1432 Aquilae: An Asynchronous Polar
Singh, K. P.; Buckley, D. A. H.; Rana, V. R. +1 more
A detailed analysis of X-ray data obtained with ROSAT, ASCA, XMM-Newton, and the Rossi X-ray Timing Explorer (RXTE) for the asynchronous polar V1432 Aquilae is presented. An analysis of Stokes polarimetry data obtained from the South African Astronomical Observatory (SAAO) is also presented. Power spectra from long-baseline ROSAT data show a spin …
A Survey of Analogs to Weak Mg II Absorbers in the Present
Charlton, Jane C.; Narayanan, Anand; Lynch, Ryan +1 more
We present the results of a survey of the analogs of weak Mg II absorbers [rest-frame equivalent width Wr(2796)<0.3 Å] at 0<z<0.3. Our sample consisted of 25 HST STIS echelle quasar spectra (R=45,000), which covered Si II λ1260 and C II λ1335 over this redshift range. Using those similar transitions as tracers of Mg II facilita…
Multiwavelength Analysis of a Solar Flare on 2002 April 15
White, Stephen M.; Zhang, Jie; Holman, Gordon D. +1 more
We carried out a multiwavelength analysis of the solar limb flare on 2002 April 15. The observations all indicate that the flare occurred in an active region with an asymmetric dipole magnetic configuration. The earlier conclusion that magnetic reconnection is occurring in a large-scale current sheet in this flare is further supported by these obs…
Near-Infrared, Kilosecond Variability of the Wisps and Jet in the Crab Pulsar Wind Nebula
Romani, R. W.; Eikenberry, S. S.; Rigaut, F. +6 more
We present a time-lapse sequence of 20 near-infrared (J and K' band) snapshots of the central 20×20 of the Crab pulsar wind nebula, taken at subarcsecond resolution with the Hokupa`a/QUIRC adaptive optics camera on the Gemini North Telescope and sampled at intervals of 10 minutes and 24 hr. It is observed that the equatorial wisps and polar knots …
In Search of the Solar Cycle Variations of p-Mode Frequencies Generated by Perturbations in the Solar Interior
Chou, Dean-Yi; Serebryanskiy, Alexander
Observations show that the solar p-mode frequencies change with the solar cycle. The horizontal phase velocity dependence of the relative frequency change, scaled by mode mass, provides depth information on the perturbation in the solar interior. Our model study suggests that variations of smoothed, scaled relative frequency change versus horizont…