Search Publications
FUSE Observation of the Narrow-Line Seyfert 1 Galaxy RE 1034+39: Dependence of Broad Emission Line Strengths on the Shape of the Photoionizing Spectrum
Baron, E.; Leighly, Karen M.; Casebeer, Darrin A.
We present an analysis from simultaneous FUSE, ASCA, and EUVE observations, as well as a reanalysis of archival HST spectra, from the extreme narrow-line Seyfert 1 Galaxy RE 1034+39 (KUG 1031+398). RE 1034+39 has an unusually hard spectral energy distribution (SED) that peaks in the soft X-rays. Its emission lines are unusual in that they can all …
A Strong X-Ray Flux Ratio Anomaly in the Quadruply Lensed Quasar PG 1115+080
Schechter, Paul L.; Fong, Wen-fai; Pooley, David +2 more
PG 1115+080 is a quadruply lensed quasar at z=1.72 whose image positions are well fit by simple models of the lens galaxy (at z=0.31). At optical wavelengths, the bright close pair of images exhibits a modest flux ratio anomaly (factors of ~1.2-1.4 over the past 22 yr) with respect to these same models. We show here that as observed in X-rays with…
Probing the Dust Responsible for Small Magellanic Cloud Extinction
Gordon, Karl D.; Sofia, Ulysses J.; Clayton, Geoffrey C. +4 more
We explore the abundances and depletion levels of elements important to dust composition in four Small Magellanic Cloud (SMC) sight lines observed with the Hubble Space Telescope. The apparent optical depth method is used to interpret the high-resolution ultraviolet absorption data toward AzV 18, AzV 456, Sk 108, and Sk 155; the latter two sight l…
An Asymmetric Outflow from the Herbig Ae Star HD 163296
Bruhweiler, F. C.; Grady, C. A.; Kimble, R. A. +2 more
We present an observational picture of the HH 409 bipolar outflow including the detection of six previously unreported Herbig-Haro knots from the Herbig Ae star HD 163296. This study combines seven years of data from ground-based Fabry-Pérot and HST coronagraphic imagery, as well as HST long-slit spectral imagery. The redshifted counterjet include…
The Current-Free Electric Double Layer in a Coronal Magnetic Funnel
Marsch, Eckart; Boswell, Roderick W.; Charles, Christine
Current-free double layers (CFDLs) have been recently discovered in a number of laboratory devices, when a low collisional plasma is forced to expand from a high magnetic field source region to a low magnetic field diffusion region. This experimental setup bears a striking resemblance to the natural conditions prevailing in the magnetic funnels of…
Electron Density Modeling of a Streamer Using LASCO Data of 2004 January and February
Thernisien, A. F.; Howard, R. A.
We present a three-dimensional reconstruction of the electron density of a streamer using a newly developed forward modeling technique. The streamer was observed by SOHO LASCO continuously at the end of 2004 January, but for this study we consider two dates, about 7 days apart. On the first day the streamer was seen ``edge-on,'' in which the coron…
Detailed Atmosphere Modeling for the Neutron Star 1E1207.4-5209: Evidence of Oxygen/Neon Atmosphere
Hailey, Charles J.; Mori, Kaya
We present a comprehensive investigation of the two broad absorption features observed in the X-ray spectrum of the neutron star 1E1207.4-5209 based on a recent analysis of the 260 ks XMM-Newton data by Mori et al. Expanding on earlier work by Hailey & Mori, we have examined all previously proposed atmospheric models for 1E1207.4-5209. Using o…
XMM-Newton View of PKS 2155-304: Hardness Ratio and Cross-Correlation Analysis of EPIC pn Observations
Maraschi, L.; Treves, A.; Zhang, Y. H. +2 more
With currently available XMM-Newton EPIC pn observations spanned over about 3 yr, we present a detailed spectral and temporal variability of the 0.2-10 keV X-ray emission from the X-ray-bright BL Lac object PKS 2155-304. The spectral variability is examined with a model-independent hardness ratio method. We find that the spectral evolution of the …
Direct Measurement of the Size of 2003 UB313 from the Hubble Space Telescope
Brown, M. E.; Schaller, E. L.; Roe, H. G. +2 more
We have used the Hubble Space Telescope to directly measure the angular size of the large Kuiper Belt object 2003 UB313. By carefully calibrating the point-spread function of a nearby field star, we measure the size of 2003 UB313 to be 34.3+/-1.4 mas, corresponding to a diameter of 2400+/-100 km or a size ~5% larger than Pluto. The V-band geometri…
GALEX Observations of ``Passive Spirals'' in the Cluster Cl 0024+17: Clues to the Formation of S0 Galaxies
Smith, Graham P.; Treu, Tommaso; Ellis, Richard S. +4 more
We present new results from deep GALEX UV imaging of the cluster Cl 0024+17 at z~0.4. Rest-frame far-UV emission is detected from a large fraction of so-called passive spiral galaxies-a significant population that exhibits spiral morphology with little or no spectroscopic evidence of ongoing star formation. This population is thought to represent …