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Discovery of a Dwarf Poststarburst Galaxy near a High Column Density Local Lyα Absorber
Stocke, John T.; Keeney, Brian A.; Giroux, Mark L. +3 more
We report the discovery of a dwarf (MB=-13.9) poststarburst galaxy coincident in recession velocity (within uncertainties) with the highest column density absorber (NHI=1015.85 cm-2 at cz=1586 km s- 1) in the 3C 273 sight line. This galaxy is by far the closest galaxy to this absorber, project…
Correction of Offset in MDI/SOHO Magnetograms
Liu, Yang; Hoeksema, J. Todd; Zhao, Xuepu
Shutter noise induces a small random shift of the zero point in full-disk magnetograms obtained by the Michelson Doppler Imager (MDI) instrument aboard SOHO. In this paper, we develop a method to remove this offset by fitting the distribution of the magnetic field strength with a Gaussian function (Ulrich et al., 2002). We also discover a systemat…
The 3-D ionization structure and evolution of NGC 7009 (Saturn Nebula)
Sabbadin, F.; Turatto, M.; Cappellaro, E. +2 more
Tomographic and 3-D analyses for extended, emission-line objects are applied to long-slit ESO NTT + EMMI high-resolution spectra of the intriguing planetary nebula NGC 7009, covered at twelve position angles. We derive the gas expansion law, the diagnostics and ionic radial profiles, the distance and the central star parameters, the nebular photo-…
A Study of a Tiny Two-Ribbon Flare Driven by Emerging Flux
Shibata, Kazunari; Akiyama, Sachiko; Brooks, David H. +6 more
We present observations of the eruption of a miniature filament that occurred near NOAA Active Region 9537 on 2001 July 14. The eruption was observed by the Hida Observatory Domeless Solar Telescope, in the Hα line center and +/-0.4 Å wings, the Solar and Heliospheric Observatory EUV Imaging Telescope (EIT) and Michelson Doppler Imager, and the Yo…
Heliospheric conditions that affect the interstellar gas inside the heliosphere
Möbius, E.; Bzowski, M.; Lallement, R. +9 more
The interstellar gas that flows through the heliosphere is strongly affected by ionization close to the Sun, in particular solar photoionization, electron impact, and charge exchange. Therefore, the interpretation of any observation of interstellar gas in the inner heliosphere hinges upon the accurate knowledge of these effects and their variation…
Hubble Space Telescope Observations of cD Galaxies and Their Globular Cluster Systems
Jordán, Andrés; Minniti, Dante; Marzke, Ronald O. +3 more
We have used WFPC2 on the Hubble Space Telescope (HST) to obtain F450W and F814W images of four cD galaxies (NGC 541 in Abell 194, NGC 2832 in Abell 779, NGC 4839 in Abell 1656, and NGC 7768 in Abell 2666) in the range 5400 km s-1<~cz<~8100 km s-1. For NGC 541, the HST data are supplemented by ground-based B and I image…
The Effective Temperatures of Hot Stars. II. The Early-O Types
Bianchi, Luciana; Garcia, Miriam
We derived the stellar parameters of a sample of Galactic early-O type stars by analyzing their UV and far-UV spectra from the Far Ultraviolet Spectroscopic Explorer (905-1187 Å), the International Ultraviolet Explorer, the Hubble Space Telescope STIS, and the Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer (1200-2000 Å). The dat…
Ultralow Iron Abundances in the Distant Hot Gas in Galaxy Groups
Buote, David A.; Brighenti, Fabrizio; Mathews, William G.
A new XMM observation of the outer regions of the galaxy group NGC 5044 indicates hot gas iron abundances of only ZFe/Zsolar~0.15 between r=0.2rvir and 0.4rvir. While the total baryon mass within the virial radius may be close to the cosmic mean value observed in rich clusters, the ratio of total iron ma…
Menzel 3: a Multipolar Nebula in the Making
Guerrero, Martín A.; Chu, You-Hua; Miranda, Luis F.
The nebula Menzel 3 (Mz 3) has arguably the most complex bipolar morphology, consisting of three nested pairs of bipolar lobes and an equatorial ellipse. Its three pairs of bipolar lobes share the same axis of symmetry but have very different opening angles and morphologies: the innermost pair of bipolar lobes shows closed-lobe morphology, whereas…
An XMM-Newton observation of the massive binary HD 159176
Gosset, E.; Owocki, S. P.; Rauw, G. +4 more
We report the analysis of an XMM-Newton observation of the close binary HD 159176 (O7 V + O7 V). The observed LX/Lbol ratio reveals an X-ray luminosity exceeding by a factor ∼7 the expected value for X-ray emission from single O-stars, therefore suggesting a wind-wind interaction scenario. EPIC and RGS spectra are fitted cons…