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The Complex Neutral Gas Dynamics of the Dwarf Starburst Galaxy NGC 625
Cannon, John M.; Skillman, Evan D.; McClure-Griffiths, N. M. +1 more
We present new multiconfiguration H I aperture synthesis imaging of the nearby dwarf starburst galaxy NGC 625 obtained with the Australia Telescope Compact Array. Total H I column density images show gas well aligned with the optical major axis and low column density H I extending to greater than 6 optical scale lengths. The H I velocity field, on…
High-z massive galaxies in the Hubble Deep Field South
Fontana, A.; Vanzella, E.; Cristiani, S. +6 more
A census of massive galaxies at redshift increasingly higher than z∼1 may provide strong constraints for the history of mass assembly and star formation. Here we report the analysis of three galaxies selected in the Hubble Deep Field South at K s≤22 on the basis of their unusually red near-IR color J-K≥3. We have used population synthesis models t…
XMM-Newton EPIC observation of the galaxy cluster A 3667
Finoguenov, A.; Briel, U. G.; Henry, J. P.
The Abell cluster of galaxies A 3667 was observed with XMM-Newton in 6 partially overlapping pointings. We present here the resulting X-ray surface brightness, temperature, entropy and pressure maps and discuss the structure of this cluster on scales from 0.1 to 30 arcmin. Based on these observations we refine the origin of the A 3667 cold front t…
The Spectral Energy Distribution and Emission-Line Properties of the Narrow-Line Seyfert 1 Galaxy Arakelian 564
Brandt, W. N.; Kriss, G. A.; Turner, T. J. +11 more
We present the intrinsic spectral energy distribution (SED) of the narrow-line Seyfert 1 galaxy (NLS1) Ark 564, constructed with contemporaneous data obtained during a multiwavelength, multisatellite observing campaign in 2000 and 2001. We compare this SED with that of the NLS1 Ton S180 and with those obtained for broad-line Seyfert 1 galaxies to …
Hubble Space Telescope WFPC2 Study of the Trapezium Cluster: The Influence of Circumstellar Disks on the Initial Mass Function
Panagia, N.; Robberto, M.; Song, J. +3 more
We have performed the first measures of mass accretion rates in the core of the Orion Nebula Cluster. Four adjacent fields centered on the Trapezium stars have been imaged in the U and B bands using the Wide Field Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope. We obtained photometry for 91 stars in the U band (F336W) and 71 stars …
A study of the expanding envelope of Nova V1974 Cyg 1992 based on IUE high resolution spectroscopy
Altamore, A.; Rossi, C.; González-Riestra, R. +2 more
We have carried out a detailed analysis of the IUE archival high resolution spectra of the classical nova V1974 Cyg 1992. The main UV resonance lines show P Cygni profiles in the first days, which change into symmetric pure emission lines, and then slowly become fainter and narrower. Lines of higher ionization species reach their peak luminosity l…
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…