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ISO-SWS Spectroscopy of NGC 1068
Lutz, D.; Genzel, R.; Sturm, E. +4 more
We present Infrared Space Observatory-Short Wave Spectrometer (ISO-SWS) spectroscopy of NGC 1068 for the complete wavelength range 2.4-45 µm at resolving power ~1500. Selected subranges have been observed at higher sensitivity and full resolving power ~2000. We detect a total of 36 emission lines and derive upper limits for 13 additional tra…
Comparison of White Dwarf Models with STIS Spectrophotometry
Bohlin, Ralph C.
Computed flux distributions for four white dwarf (WD) stars with nearly pure hydrogen atmospheres are tied to the Vega flux scale with V-band Landolt photometry. With broadband photometric precision in the range 0.2%-0.4%, Space Telescope Imaging Spectrograph (STIS) low-dispersion spectrophotometry tightly constrains the relative continuum fluxes …
Detection of Dark Matter Concentrations in the Field of Cl 1604+4304 from Weak Lensing Analysis
Umetsu, Keiichi; Futamase, Toshifumi
We present a weak lensing analysis of a region around the galaxy cluster Cl 1604+4304 (z=0.897) on the basis of the deep observations with the Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 (WFPC2). We apply a variant of Schneider's aperture mass technique to the observed WFPC2 field and obtain the distribution of weak lensing signal-t…
Alfvénic turbulence in the polar wind: A statistical study on cross helicity and residual energy variations
Bavassano, B.; Pietropaolo, E.; Bruno, R.
A study of MHD turbulence properties in the polar wind has been performed with Ulysses data. The parameters under examination are the normalized cross helicity and the normalized residual energy. The correlation coefficient between velocity and magnetic field fluctuation vectors has also been computed. Both southern and northern phases of full imm…
A Lyα Bright Jet from a Herbig AE Star
Linsky, J. L.; Bruhweiler, F. C.; Boggess, A. +5 more
We report the detection in Lyα of a collimated, bipolar outflow (HH 409) associated with the 1.5-10 Myr old Herbig Ae star HD 163296. A blueshifted jet is visible in Lyα and Si III extending toward the southwest for at least 6" (725 AU). The combination of low line-of-sight extinction and relative faintness of the central star near Lyα enables us …
X-rays and regions of star formation: a combined ROSAT-HRI/near-to-mid IR study of the rho Oph dark cloud
Grosso, N.; Bontemps, S.; André, P. +2 more
We have obtained two deep exposures of the rho Oph cloud core region with the ROSAT High Resolution Imager. The improved position accuracy (1arcsec -6arcsec ) with respect to previous recent X-ray observations (ROSAT PSPC, and ASCA ) allows us to remove positional ambiguities for the detected sources. We also cross-correlate the X-ray positions wi…
Current Helicity of the Large-Scale Photospheric Magnetic Field
Pevtsov, Alexei A.; Latushko, Sergei M.
This paper presents the first results of a study of current helicity of the large-scale magnetic field (LSMF) using full-disk longitudinal Blong magnetograms from the Michelson Doppler Imager on board the SOHO spacecraft. We employ a known technique to reconstruct the vector magnetic field under the assumption of relatively slow evoluti…
Wind properties of Wolf-Rayet stars at low metallicity: Sk 41 (SMC)
Crowther, P. A.
The stellar properties of Sk 41 (AB4, WN5h), the only known single Wolf-Rayet star in the SMC, are derived from ultraviolet (IUE), optical (AAT) and near-IR (NTT) spectroscopy. Contrary to expectations for low metal environments, the stellar properties of Sk 41 are typical of equivalent WN stars in the Galaxy and LMC, with T* ~ 42kK, lo…
Dwarf spheroidal galaxies in the M81 group imaged with WFPC2
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +7 more
We obtained HST/WFPC2 images of the dwarf spheroidal (dSph) galaxies K61, K63, K64, DDO78, BK6N, and kk77 in the M81 group. Our color-magnitude diagrams show red giant branches with tips (TRGB) falling within the range of I = [23.8 -24.0] mag. The derived true distance moduli (DM) of the 6 dSphs ranging from 27.71 to 27.93 mag are consistent with …
Rossby waves on the Sun as revealed by solar `hills'
Kuhn, J. R.; Bush, R. I.; Scherrer, P. +1 more
It is a long-standing puzzle that the Sun's photosphere-its visible surface-rotates differentially, with the equatorial regions rotating faster than the poles. It has been suggested that waves analogous to terrestrial Rossby waves, and known as r-mode oscillations, could explain the Sun's differential rotation: Rossby waves are seen in the oceans …