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A Spitzer Study of Asymptotic Giant Branch Stars. III. Dust Production and Gas Return in Local Group Dwarf Irregular Galaxies
Skillman, Evan D.; Boyer, Martha L.; Gehrz, Robert D. +2 more
We present the third and final part of a census of asymptotic giant branch (AGB) stars in Local Group dwarf irregular (dIrr) galaxies. Papers I and II presented the results for WLM and IC 1613. Included here are Phoenix, LGS 3, DDO 210, Leo A, Pegasus dIrr, and Sextans A. Spitzer photometry at 3.6, 4.5, 5.8, and 8 µm are presented, along wit…
Faint recombination lines in Galactic PNe with a [WC] nucleus
García-Rojas, J.; Peña, M.; Peimbert, A.
Aims: We present spatially resolved high-resolution spectrophotometric data for the planetary nebulae PB 8, NGC 2867, and PB 6. We have analyzed two knots in NGC 2867 and PB 6 and one in PB 8. The three nebulae are ionized by [WC] type nuclei: early [WO] for PB 6 and NGC 2867 and [WC 5-6] in the case of PB 8. Our aim is to study the behavior of th…
Quasar induced galaxy formation: a new paradigm?
Elbaz, D.; Jahnke, K.; Pantin, E. +2 more
Aims: We discuss observational evidence that quasars play a key role in the formation of galaxies, starting from the detailed study of the quasar HE0450-2958 and extending the discussion to a series of converging evidence that radio jets may trigger galaxy formation.
Methods: We use mid infrared imaging with VISIR at the ESO-VLT to model the m…
The Nature of Unresolved Soft X-Ray Emission from the Galactic Disk
Mitsuda, Kazuhisa; Yamasaki, Noriko Y.; McCammon, Dan +4 more
Although about 40% of the soft X-ray background emission in 0.4 to 1keV range has extragalactic origins and thus is totally blocked by the galactic absorption in midplane directions, it decreases at most by about 20% in midplane. Suzaku observation of the direction, (l, b) = (235°, 0°), showed an OVII Kα emission intensity comparable with that of …
High-Resolution X-Ray Spectroscopy of the Evolving Shock in the 2006 Outburst of RS Ophiuchi
Ness, J. -U.; Eyres, S. P. S.; Evans, A. +9 more
The evolution of the 2006 outburst of the recurrent nova RS Ophiuchi was followed with 12 X-ray grating observations with Chandra and XMM-Newton. We present detailed spectral analyses using two independent approaches. From the best data set, taken on day 13.8 after outburst, we reconstruct the temperature distribution and derive elemental abundanc…
Modelling shock drift acceleration of electrons at the reconnection outflow termination shock in solar flares. Observational constraints and parametric study
Mann, G.; Aurass, H.; Warmuth, A.
Context: The acceleration of electrons to nonthermal energies in solar flares is one of the main unsolved questions in solar physics. One possibility for producing these energetic electrons is acceleration at the reconnection outflow termination shock (TS).
Aims: By comparing theoretical results with observations of nonthermal electrons, we de…
The chemical composition of carbon stars. The R-type stars
Abia, C.; Cristallo, S.; Plez, B. +2 more
Aims. The aim of this work is to shed some light on the problem of the formation of carbon stars of R-type from a detailed study of their chemical composition.
Methods: We use high-resolution and high signal-to-noise optical spectra of 23 R-type stars (both early- and late-types) selected from the Hipparcos catalogue. The chemical analysis is …
Numerical Simulation of Excitation and Propagation of Helioseismic MHD Waves: Effects of Inclined Magnetic Field
Kosovichev, A. G.; Parchevsky, K. V.
Investigation of propagation, conversion, and scattering of MHD waves in the Sun is very important for understanding the mechanisms of observed oscillations and waves in sunspots and active regions. We have developed a three-dimensional linear MHD numerical model to investigate the influence of the magnetic field on excitation and properties of th…
MCAO near-IR photometry of the globular cluster NGC 6388: MAD observations in crowded fields
Moretti, A.; Falomo, R.; Anderson, J. +15 more
Context: Deep photometry of crowded fields, such as Galactic globular clusters, is severely limited by the resolution of ground-based telescopes. On the other hand, the Hubble Space Telescope does not have the near-infrared (NIR) filters needed to allow large color baselines.
Aims: In this work we demonstrate how ground based observations can …
Hubble Space Telescope survey of the Perseus Cluster - I. The structure and dark matter content of cluster dwarf spheroidals
Conselice, Christopher J.; Penny, Samantha J.; de Rijcke, Sven +1 more
We present the results of a Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) study of dwarf galaxies in the core of the rich nearby Perseus Cluster, down to MV = -12. We identify 29 dwarfs as cluster members, 17 of which are previously unstudied. All the dwarfs we examine are remarkably smooth in appearance, and lack inter…