Search Publications
Mid-IR Observations and a Revised Time Delay for the Gravitational Lens System Quasar HE 1104-1805
Kochanek, Christopher S.; Falco, Emilio E.; Poindexter, Shawn +1 more
The mid-IR flux ratios FA/FB=2.84+/-0.06 of the two images of the gravitationally lensed quasar HE 1104-1805 show no wavelength dependence to within 3% across 3.6-8.0 µm, show no time dependence over 6 months, and agree with the broad emission-line flux ratios. This indicates that the mid-IR emission likely comes from s…
A Systematic Search for High Surface Brightness Giant Arcs in a Sloan Digital Sky Survey Cluster Sample
Allam, S.; Annis, J.; Diehl, H. T. +8 more
We present the results of a search for gravitationally lensed giant arcs conducted on a sample of 825 SDSS galaxy clusters. Both a visual inspection of the images and an automated search were performed, and no arcs were found. This result is used to set an upper limit on the arc probability per cluster. We present selection functions for our surve…
A Radio Nebula Surrounding the Ultraluminous X-Ray Source in NGC 5408
Kaaret, Philip; Corbel, Stéphane; Lang, Cornelia C. +1 more
New radio observations of the counterpart of the ultraluminous X-ray source in NGC 5408 show for the first time that the radio emission is resolved with an angular size of 1.5"-2.0". This corresponds to a physical size of 35-46 pc, and rules out interpretation of the radio emission as beamed emission from a relativistic jet. In addition, the radio…
Smooth and Starburst Tidal Tails in the GEMS and GOODS Fields
Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Ferguson, Thomas +1 more
GEMS and GOODS fields were examined to z~1.4 for galaxy interactions and mergers. The basic morphologies are familiar: antennae with long tidal tails, tidal dwarfs, and merged cores; M51-type galaxies with disk spirals and tidal arm companions; early-type galaxies with diffuse plumes; equal-mass grazing collisions; and thick J-shaped tails beaded …
Discovery of Probable Relativistic Fe Emission and Absorption in the Cloverleaf Quasar H 1413+117
Agol, E.; Dai, X.; Chartas, G. +2 more
We present results from Chandra and XMM-Newton observations of the low-ionization broad absorption line (LoBAL) quasar H 1413+117. Our spatial and spectral analysis of a recent deep Chandra observation confirms a microlensing event in a previous Chandra observation performed about five years earlier. We present constraints on the structure of the …
On the Metallicity Dependence of the 24 µm Luminosity as a Star Formation Tracer
Battaner, E.; Relaño, M.; Vílchez, J. M. +2 more
We investigate the use of the rest-frame 24 µm luminosity as an indicator of the star formation rate (SFR) in galaxies with different metallicities by comparing it to the (extinction-corrected) Hα luminosity. We carry out this analysis in two steps: First, we compare the emission from H II regions in different galaxies with metallicities bet…
Observations of O I and Ca II Emission Lines in Quasars: Implications for the Site of Fe II Line Emission
Kawara, K.; Oyabu, S.; Tsuzuki, Y. +1 more
We present results of the near-infrared (IR) spectroscopy of six quasars whose redshifts range from 0.158 to 1.084. Combined with the satellite ultraviolet data, the relative line strengths of O I λ1304, O I λ8446, O I λ11287, and the near-IR Ca II triplet are given. In addition, the corresponding O I line strengths measured in normal Seyfert 1s a…
Density and Magnetic Field Signatures of Interplanetary 1/f Noise
Romoli, M.; Bemporad, A.; Poletto, G. +4 more
We investigate the occurrence of 1/f noise in the interplanetary density and the magnetic field at varying heliocentric latitudes. The characteristic spectral amplitudes can be found in Ulysses density and magnetic data in the expected frequency ranges at all available latitudes, ranging from the ecliptic plane to more than 80°. Average spectra in…
Encounter of the Ulysses Spacecraft with the Ion Tail of Comet MCNaught
Geiss, J.; McComas, D. J.; Smith, E. J. +12 more
Comet McNaught was the brightest comet observed from Earth in the last 40 years. For a period of five days in early 2007 February, four instruments on the Ulysses spacecraft directly measured cometary ions and key properties of the interaction of the comet's ion tail with the high-speed solar wind from the polar regions of the Sun. Because of the …
The Coronal-dimming Footprint of a Streamer-Puff Coronal Mass Ejection: Confirmation of the Magnetic-Arch-Blowout Scenario
Moore, Ronald L.; Sterling, Alphonse C.
A streamer puff is a recently identified variety of coronal mass ejection (CME) of narrow to moderate width. It (1) travels out along a streamer, transiently inflating the streamer but leaving it largely intact, and (2) occurs in step with a compact ejective flare in an outer flank of the base of the streamer. These aspects suggest the following m…