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Optical and mid-infrared observations of the planetary nebula NGC 6781
Guerrero, Martín A.; Ramos-Larios, Gerardo; Phillips, J. P.
Although the planetary nebula NGC 6781 appears to possess an elliptical morphology, its kinematic and emission characteristics are in many ways unusual, and it is possible that it may represent a bipolar source oriented close to the line of sight. We shall present deep imaging of this nebula in [O III]λ5007, Hα and [N II]λ6584, and using broad-ban…
Appearance of layered structures in numerical simulations of polydisperse bodies accretion: Application to cometary nuclei
Lasue, J.; Kofman, W.; Levasseur-Regourd, A. C. +2 more
A model for the aggregation of size distribution of cometesimals (Gaussian or power law) into cometary nuclei is developed. Upon disruption induced by collisions, sticking and evolution of the tensile strength and density of the cometesimals by sintering processes are taken into account. The resulting cometary nuclei present specific internal stru…
Blue Luminous Stars in Nearby Galaxies—UIT 005: A Possible Link to the Luminous Blue Variable Stage
Meynet, G.; Lennon, D. J.; Herrero, A. +2 more
A detailed study of the blue supergiant UIT 005 (B2-2.5Ia+) in M 33 is presented. The results of our quantitative spectral analysis indicate that the star is a very luminous (log L/L sun ~ 5.9 dex) and massive (M ~ 50 M sun) object, showing a very high nitrogen-to-oxygen ratio in its surface (N/O~8, by mass). Based…
The Evolution of Radio Galaxies and X-Ray Point Sources in Coma Cluster Progenitors since z ~ 1.2
Stocke, John T.; Evrard, August E.; Hart, Quyen N. +2 more
Using Chandra imaging spectroscopy and Very Large Array (VLA) L-band radio maps, we have identified radio sources at P 1.4 GHz >= 5 × 1023 W Hz-1 and X-ray point sources (XPSs) at L 0.3-8 keV >= 5 × 1042 erg s-1 in L > L* galaxies in 12 high-redshift (0.4 < z < 1.2) c…
XMM Follow-up Observations of Three Swift BAT-selected Active Galactic Nuclei
Reynolds, C. S.; Mushotzky, R. F.; Koss, M. +2 more
We present XMM-Newton observations of three active galactic nuclei (AGNs) taken as part of a hunt to find very heavily obscured Compton-thick AGNs. For obscuring columns greater than 1025 cm-2, AGNs are only visible at energies below 10 keV via reflected/scattered radiation, characterized by a flat power law. We therefore sel…
Aspects of magnetopause/magnetosphere response to interplanetary discontinuities, and features of magnetopause Kelvin-Helmholtz waves
Farrugia, C. J.; Gratton, F. T.
We describe (i) perturbations of the magnetopause/magnetosphere elicited by an interplanetary discontinuity and (ii) the production of Kelvin-Helmholtz waves on the magnetopause. These are two large topics, so for reasons of space we combine both features in a single data example, supporting the observations by theory. Correspondingly, the observa…
Cluster observations of bow shock energetic ion transport through the magnetosheath into the cusp
Fuselier, S. A.; Kronberg, E.; Nykyri, K. +2 more
The observation of energetic particles by polar orbiting satellites in the magnetospheric cusp resulted in a controversy about their source region. It has been suggested that these cusp energetic particles (CEP) with significant fluxes from magnetosheath energies up to several hundred keV/e are accelerated locally in the cusp by the turbulence fou…
Energetic electron spectra in Saturn's plasma sheet
Krupp, N.; Krimigis, S. M.; Mitchell, D. G. +2 more
The differential spectra of energetic electrons (27-400 keV) in Saturn's plasma sheet can be characterized by power law or kappa distributions. Using all available fluxes from 2005 to 2010, fits to these distributions reveal a striking and consistent pattern of radial dependence in Saturn's plasma sheet (∣z∣ < 1 RS = 60,268 km). The …
Integral field spectroscopy in the near infrared of NGC 3125-A and SBS 0335-052
Sauvage, M.; Cresci, G.; Thompson, R. +1 more
We present integral field spectroscopy in the near infrared of the nearby dwarf starburst galaxy NGC 3125-A and of the low metallicity dwarf galaxy SBS 0335-052. The use of adaptive optics in the observations produces sub-arcsecond angular resolution. We pinpoint the star forming cores of both galaxies, identify relevant ISM components such as dus…
Long-term X-ray Variability Study of IC342 from XMM-Newton Observations
Mak, Daisy S. Y.; Pun, Chun S. J.; Kong, Albert K. H.
We presented the results of an analysis of four XMM-Newton observations of the starburst galaxy IC342 taken over a four-year span from 2001 to 2005, with an emphasis on investigating the long-term flux and spectral variability of the X-ray point sources. We detected a total of 61 X-ray sources within 35' × 30' of the galaxy down to a luminosity of…