Search Publications
Dust Scattering and the Radiation Pressure Force in the M82 Superwind
Thompson, Todd A.; Martini, Paul; Coker, Carl T.
Radiation pressure on dust grains may be an important physical mechanism driving galaxy-wide superwinds in rapidly star-forming galaxies. We calculate the combined dust and gas Eddington ratio (Γ) for the archetypal superwind of M82. By combining archival Galaxy Evolution Explorer data, a standard dust model, Monte Carlo dust scattering calculatio…
The XMM Deep survey in the CDF-S. V. Iron K lines from active galactic nuclei in the distant Universe
Vignali, C.; Gilli, R.; Ranalli, P. +11 more
Context. X-ray spectroscopy of active galactic nuclei (AGN) offers the opportunity to directly probe the inner regions of the accretion disk. Reflection of the primary continuum on the circumnuclear accreting matter produces features in the X-ray spectrum that help to explore the physics and the geometry of the innermost region, close to the centr…
Source Regions of the Interplanetary Magnetic Field and Variability in Heavy-ion Elemental Composition in Gradual Solar Energetic Particle Events
Wang, Yi-Ming; Ko, Yuan-Kuen; Ng, Chee K. +2 more
Gradual solar energetic particle (SEP) events are those in which ions are accelerated to their observed energies by interactions with a shock driven by a fast coronal mass ejection (CME). Previous studies have shown that much of the observed event-to-event variability can be understood in terms of shock speed and evolution in the shock-normal angl…
Timing and spectral analysis of the unusual X-ray transient XTE J0421+560/CI Camelopardalis
Bartlett, E. S.; Coe, M. J.; Uttley, P. +2 more
We present a detailed X-ray study of the 2003 XMM-Newton observation of the high-mass X-ray binary XTE J0421+560/CI Camelopardalis. The continuum of the X-ray spectrum is well described by a flat power law (Γ = 1.0 ± 0.2) with a large intrinsic absorbing column (NH = (4.4 ± 0.5) × 1023 cm-2). We have decomposed the…
The nature of the H2-emitting gas in the Crab nebula
Richardson, C. T.; Fabian, A. C.; Ferland, G. J. +4 more
Understanding how molecules and dust might have formed within a rapidly expanding young supernova remnant is important because of the obvious application to vigorous supernova activity at very high redshift. In previous papers, we have mapped the Crab nebula (the Crab) in a rotovibrational H2 emission line, and then measured the molecul…
Emission spectrum of ionized gas in the irregular galaxy Holmberg II
Moiseev, A. V.; Lozinskaya, T. A.; Egorov, O. V.
We studied the ionized gas spectra of star-forming regions in the Holmberg II galaxy using optical long-slit spectroscopic observations made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS). We estimated the oxygen, nitrogen, sulphur, neon and argon abundances in individual H II regions a…
The color dependent morphology of the post-AGB star HD 161796
Waters, L. B. F. M.; Jeffers, S. V.; Min, M. +3 more
Context. Many protoplanetary nebulae show strong asymmetries in their surrounding shells, pointing to asymmetries during the mass loss phase. Questions concerning the origin and the onset of deviations from spherical symmetry are important for our understanding of the evolution of these objects. Here we focus on the circumstellar shell of the post…
Discovery of X-Ray Emission from Young Suns in the Small Magellanic Cloud
Güdel, M.; Gruendl, R. A.; Chen, Y. +11 more
We report the discovery of extended X-ray emission within the young star cluster NGC 602a in the Wing of the Small Magellanic Cloud (SMC) based on observations obtained with the Chandra X-Ray Observatory. X-ray emission is detected from the cluster core area with the highest stellar density and from a dusty ridge surrounding the H II region. We us…
Ensemble forecasting of coronal mass ejections using the WSA-ENLIL with CONED Model
Odstrcil, D.; Taktakishvili, A.; Pulkkinen, A. +3 more
The combination of the Wang-Sheeley-Arge (WSA) coronal model, ENLIL heliospherical model version 2.7, and CONED Model version 1.3 (WSA-ENLIL with CONED Model) was employed to form ensemble forecasts for 15 halo coronal mass ejections (halo CMEs). The input parameter distributions were formed from 100 sets of CME cone parameters derived from the CO…
HerMES: The Far-infrared Emission from Dust-obscured Galaxies
Pérez-Fournon, I.; Bock, J.; Cooray, A. +21 more
Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ~ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg2 of the Cosmic Evolution Survey. The 30…