Search Publications
Modeling of the HerMES Submillimeter Source Lensed by a Dark Matter Dominated Foreground Group of Galaxies
Pérez-Fournon, I.; Rodighiero, G.; Valtchanov, I. +85 more
We present the results of a gravitational lensing analysis of the bright z s = 2.957 submillimeter galaxy (SMG) HERMES found in the Herschel/SPIRE science demonstration phase data from the Herschel Multi-tiered Extragalactic Survey (HerMES) project. The high-resolution imaging available in optical and near-IR channels, along with CO emi…
A Statistical Model for the γ-ray Variability of the Crab Nebula
Yuan, Qiang; Zhang, Bing; Wu, Xue-Feng +3 more
A statistical scenario is proposed to explain the γ-ray variability and flares of the Crab Nebula, which were observed recently by the Fermi/LAT. In this scenario electrons are accelerated in a series of knots, whose sizes follow a power-law distribution. These knots presumably move outward from the pulsar and have a distribution in the Doppler bo…
Seasonal Changes in Titan's Surface Temperatures
Flasar, F. M.; Coustenis, A.; Jennings, D. E. +9 more
Seasonal changes in Titan's surface brightness temperatures have been observed by Cassini in the thermal infrared. The Composite Infrared Spectrometer measured surface radiances at 19 µm in two time periods: one in late northern winter (LNW; Ls = 335°) and another centered on northern spring equinox (NSE; Ls = 0°). In b…
Ultraviolet Spectroscopy of Circumnuclear Star Clusters in M83
Leitherer, Claus; Chandar, Rupali; Wofford, Aida
We analyze archival HST/STIS/FUV-MAMA imaging and spectroscopy of 13 compact star clusters within the circumnuclear starburst region of M83, the closest such example. We compare the observed spectra with semi-empirical models, which are based on an empirical library of Galactic O and B stars observed with IUE, and with theoretical models, which ar…
Plasmoid Releases in the Heliospheric Current Sheet and Associated Coronal Hole Boundary Layer Evolution
Sauvaud, J. -A.; Luhmann, J. G.; Farrugia, C. J. +10 more
As the heliospheric current sheet (HCS) is corotating past STEREO-B, near-Earth spacecraft ACE, Wind and Cluster, and STEREO-A over more than three days between 2008 January 10 and 14, we observe various sections of (near-pressure-balanced) flux-rope- and magnetic-island-type plasmoids in the associated heliospheric plasma sheet (HPS). The plasmoi…
XMM-Newton Observations of MBM 12: More Constraints on the Solar Wind Charge Exchange and Local Bubble Emissions
Snowden, Steven L.; Smith, Randall K.; Plucinsky, Paul P. +3 more
We present the first analysis of an XMM-Newton observation of the nearby molecular cloud MBM 12. We find that in the direction of MBM 12 the total O VII (0.57 keV) triplet emission is 1.8+0.5 -0.6 photons cm-2 s-1 sr-1 (or line units, LU) while for the O VIII (0.65 keV) line emission we find a…
Maximum Coronal Mass Ejection Speed as an Indicator of Solar and Geomagnetic Activities
Goode, P. R.; Gopalswamy, N.; Yurchyshyn, V. B. +4 more
We investigate the relationship between the monthly averaged maximal speeds of coronal mass ejections (CMEs), international sunspot number (ISSN), and the geomagnetic Dst and Ap indices covering the 1996-2008 time interval (solar cycle 23). Our new findings are as follows. (1) There is a noteworthy relationship between monthly averaged maximum CME…
Multiwavelength Observations of the Gamma-Ray Blazar PKS 0528+134 in Quiescence
Lähteenmäki, A.; Umana, G.; Lott, B. +29 more
We present multiwavelength observations of the ultraluminous blazar-type radio loud quasar PKS 0528+134 in quiescence during the period 2009 July-December. Four Target-of-Opportunity observations with the XMM-Newton satellite in the 0.2-10 keV range were supplemented with optical observations at the MDM Observatory, radio and optical data from the…
Probing Population III Stars in Galaxy IOK-1 at z = 6.96 Through He II Emission
Fan, Xiaohui; Jiang, Linhua; Cai, Zheng +7 more
The He II λ1640 emission line has been suggested as a direct probe of Population III (Pop III) stars at high redshift, since it can arise from highly energetic ionizing photons associated with hot, metal-free stars. We use the Hubble Space Telescope WFC3/F130N IR narrowband filter to probe He II λ1640 emission in galaxy IOK-1 at z = 6.96. The sens…
Forward Modeling Cavity Density: A Multi-instrument Diagnostic
Gibson, S. E.; Schmit, D. J.
The thermodynamic properties of coronal prominence cavities present a unique probe into the energy and mass budget of prominences. Using a three-dimensional morphological model, we forward model the polarization brightness and extreme-ultraviolet (EUV) emission of a cavity and its surrounding streamer. Using a genetic algorithm, we find the best-f…