Search Publications
The 5 hr Pulse Period and Broadband Spectrum of the Symbiotic X-Ray Binary 3A 1954+319
Fürst, Felix; Grinberg, Victoria; Pottschmidt, Katja +7 more
We present an analysis of the highly variable accreting X-ray pulsar 3A 1954+319 using 2005-2009 monitoring data obtained with INTEGRAL and Swift. This considerably extends the pulse period history and covers flaring episodes in 2005 and 2008. In 2006 the source was identified as one of only a few known symbiotic X-ray binaries (SyXBs), i.e., syst…
Spitzer Imaging of Herschel-atlas Gravitationally Lensed Submillimeter Sources
Smail, I.; Rodighiero, G.; Valtchanov, I. +49 more
We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities >100 mJy at 500 µm, but are not visible in existing optical imaging. We fit light profiles to each component of the lensi…
Measuring Gravitational Lensing Flexion in A1689 Using an Analytic Image Model
Schechter, Paul L.; Cain, Benjamin; Bautz, M. W.
Measuring dark matter substructure within galaxy cluster halos is a fundamental probe of the ΛCDM model of structure formation. Gravitational lensing is a technique for measuring the total mass distribution which is independent of the nature of the gravitating matter, making it a vital tool for studying these dark-matter-dominated objects. We pres…
Solar Cycle Variations in the Elemental Abundance of Helium and Fractionation of Iron in the Fast Solar Wind: Indicators of an Evolving Energetic Release of Mass from the Lower Solar Atmosphere
McIntosh, Scott W.; Kasper, Justin C.; Stevens, Michael L. +2 more
We present and discuss the strong correspondence between evolution of the emission length scale in the lower transition region and in situ measurements of the fast solar wind composition during the most recent solar minimum. We combine recent analyses demonstrating the variance in the (supergranular) network emission length scale measured by the S…
Radio Observations of the Solar Corona During an Eclipse
Ramesh, R.; Kathiravan, C.; Barve, Indrajit V. +1 more
We carried out radio observations of the solar corona at 170 MHz during the eclipse of 2008 August 1, from the Gauribidanur observatory located about 100 km north of Bangalore in India. The results indicate the presence of a discrete radio source of very small angular dimension (≈15'') in the corona from where the observed radiation originated.
He II Lyβ Gunn-Peterson Absorption: New HST Observations and Theoretical Expectations
Anderson, Scott F.; Pieri, Matthew; Schneider, Donald P. +7 more
Observations of He II Lyα Gunn-Peterson troughs have proved to be a valuable probe of the epoch of helium reionization at z ~ 3. Since this optical depth can become unmeasurably large even for modest He II fractions, various alternate techniques have been proposed to push to higher redshift, and among the more promising is looking at higher-order …
Removal of Titan's Atmospheric Noble Gases by Their Sequestration in Surface Clathrates
Mousis, Olivier; Lunine, Jonathan I.; Mandt, Kathleen E. +3 more
A striking feature of the atmosphere of Titan is that no heavy noble gases other than argon were detected by the Gas Chromatograph Mass Spectrometer aboard the Huygens probe during its descent to Titan's surface in 2005 January. Here we provide an explanation of the mysterious absence or rarity of these noble gases in Titan's atmosphere: the therm…
Radio Evidence of Break-out Reconnection?
Mann, G.; Karlický, M.; Aurass, H. +1 more
We reconsider the 2003 October 28 X17 flare/coronal mass ejection (CME), studying the five minutes immediately before the impulsive flare phase (not discussed in previous work). To this aim we examine complementary dynamic radio spectrograms, single frequency polarimeter records, radio images, space-based longitudinal field magnetograms, and ultra…
Testing Stellar Population Synthesis Models with Sloan Digital Sky Survey Colors of M31's Globular Clusters
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +1 more
Accurate stellar population synthesis models are vital in understanding the properties and formation histories of galaxies. In order to calibrate and test the reliability of these models, they are often compared with observations of star clusters. However, relatively little work has compared these models in the ugriz filters, despite the recent wi…
Constraints on Quasar Lifetimes and Beaming from the He II Lyα Forest
Furlanetto, Steven R.; Lidz, Adam
We show that comparisons of He II Lyα forest lines of sight to nearby quasar populations can strongly constrain the lifetimes and emission geometry of quasars. By comparing the He II and H I Lyα forests along a particular line of sight, one can trace fluctuations in the hardness of the radiation field (which are driven by fluctuations in the He II…