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Young massive stars in the ISOGAL survey. I. VLA observations of the ISOGAL l=+45 field
Felli, M.; Testi, L.; Taylor, G. B.
We present VLA radio continuum observations at 3.6 and 6 cm of a ~ 0.65 sq. deg. field in the galactic plane at l=+45(deg) . These observations are meant to be used in a comparison with ISO observations at 7 and 15 mu m of the same region. In this paper we compare the radio results with other radio surveys and with the IRAS-PSC. At 3.6 and/or 6 cm…
A complex Lyman limit system at z=1.9 towards HS 1103+6416
Reimers, D.; Hagen, H. -J.; Burles, S. +3 more
We analyse absorption lines in optical and ultraviolet spectra of the bright (V=15.8, z=2.19) QSO HS 1103+6416. High-resolution (FWHM =8 km s(-1) ) optical spectra have been obtained with the Keck 10 m telescope in the range from 3180 to 5780 Angstroms. Ultraviolet observations in the range from 1150 to 3280 Angstroms were performed with the FOS a…
Chemically Decoupled Nuclei in the Spiral Galaxies NGC 4216 and NGC 4501
Burenkov, A. N.; Sil'chenko, O. K.; Vlasyuk, V. V.
By using bidimensional spectral data obtained at the 6 m telescope for the Virgo spirals NGC 4216 and NGC 4501, we have found chemically distinct metal-rich nuclei in these galaxies. Under the assumption of equal ages for the nuclear and bulge stellar populations, the metallicity difference between the nuclei and their environments in the galaxies…
The Relationship between Ultraviolet Line Emission and Magnetic Field Strength in Magnetic Cataclysmic Variables
Howell, Steve B.; Cash, Jennifer; Mason, Keith O. +1 more
We present the first UV spectral observations of six magnetic cataclysmic variables discovered by the ROSAT Wide Field Camera (WFC). Using the^ International Ultraviolet Explorer (IUE), 1200-3400 Å spectra were obtained of the AM Herculis stars RE 0531-46, RE 1149+28, RE 1844-74, QS Tel (RE 1938-46), and HU Aqr (RE 2107-05) and the DQ Herculis sta…
ROSAT X-ray observations of the interacting pair of galaxies NGC 4410: evidence for a central starburst
Hensler, G.; Tschöke, D.; Junkes, N.
We present X-ray observations of the interacting pair of galaxies NGC 4410a/b with the ROSAT HRI and PSPC. The ROSAT HRI images reveal a point-like source corresponding to NGC 4410a and an X-ray halo, extending 10'' from the nucleus toward the southeast. The halo emission accounts for ~ 1/3 (LX = 1.3\tento{41} erg s(-1) in the 0.1-2.4 k…
Precise GRB source locations from the renewed interplanetary network
Hurley, K.; Kouveliotou, C.; Cline, T. L. +14 more
A new interplanetary network (IPN) is made possible by the modification of the NEAR mission, now at 2 AU distance. With Ulysses and the near-Earth GRB monitors, this fully long-baseline network will produce GRB localizations at a rate of about one per week, with accuracies varying from several to tens of arc minutes. Given the delays inherent in t…
Spiral galaxy distance indicators based on near-infrared photometry
de Grijs, Richard; Peletier, Reynier F.
We compare two methods of distance determination to spiral galaxies using optical/near-infrared (NIR) observations, the (I-K) versus MK colour-absolute magnitude (CM) relation and the I- and K-band Tully-Fisher relation (TFR). Dust-free colours and NIR absolute magnitudes greatly enhance the usefulness of the NIR CM relation as a distan…
The induced magnetosphere of comet Halley 4. Comparison of in situ observations and numerical simulations
Neubauer, F. M.; Gombosi, T. I.; Israelevich, P. L. +3 more
A comprehensive comparison between the results of a multiscale three-dimensional adaptive MHD model of the comet Halley magnetosphere and in situ observations by the Giotto mission is presented. It is shown how a steady state model can describe the effects of the varying IMF direction on the cometary magnetosphere. The simulation results reproduce…
Temporal variability in the electron density at the solar transition region
Doyle, J. G.; Keenan, F. P.; O'Shea, E. +1 more
The electron density as measured in the transition region of a coronal hole, a `quiet' Sun region at disk center plus an active region shows variations of up to a factor of two at T_e ~ 1.5 105 K, lasting at most only a few minutes. There is remarkable agreement between the number of such variations, their temporal variability and durat…
Echelle Spectroscopy of Interstellar Absorption toward MU Columbae with the Goddard High Resolution Spectrograph
Savage, B. D.; Sembach, K. R.; Ebbets, D. C. +17 more
Goddard High Resolution Spectrograph echelle-mode observations of the interstellar absorption lines of Mg II, Si IV, C IV, and N V toward mu Columbae (HD 38666) are presented. The observations have a spectral resolution of 3.5 km s^-1 and signal-to-noise ratios (S/Ns) of 20-200. The mu Col sight line (l=237.3d, b=-27.1d, d=0.40 kpc, z=-0.18 kpc) e…