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Gemini observations of Wolf-Rayet stars in the Local Group starburst galaxy IC 10
Smartt, S. J.; Crowther, P. A.; Royer, P. +2 more
We present Gemini-N GMOS and CFHT MOS spectroscopy of Wolf-Rayet candidates in the Local Group dwarf galaxy IC 10 that were previously identified by Massey et al. and Royer et al. From the present spectroscopic survey, the WC/WN ratio for IC 10 remains unusually high, given its low metallicity, although none of the WC9 stars suspected from narrow-…
The pre-main sequence spectroscopic binary AK Scorpii revisited
Andersen, J.; Alencar, S. H. P.; Batalha, C. +4 more
We present an analysis of 32 high-resolution echelle spectra of the pre-main sequence spectroscopic binary AK Sco obtained during 1998 and 2000, as well as a total of 72 photoelectric radial-velocity observations from the period 1986-1994. These data allow considerable improvement of the period and other orbital parameters of AK Sco. Our analysis …
The conspicuous absence of X-ray emission from carbon-enriched Wolf-Rayet stars
Hamann, W. -R.; Oskinova, L. M.; Ignace, R. +2 more
The carbon-rich WC5 star WR 114 was not detected during a 15.9 ksec XMM-Newton, observation, implying an upper limit to the X-ray luminosity of LX <∼ 2.5x 1030 erg s-1 and to the X-ray to bolometric luminosity ratio of LX/Lbol <∼ 4*E-9. This confirms indications from earlier l…
An XMM-Newton observation of the globular cluster Omega Centauri
Webb, N. A.; Barret, D.; Gendre, B.
We report on a deep XMM-Newton EPIC observation of the globular cluster Omega Cen performed on August 13th, 2001. We have detected 11 and 27 faint X-ray sources in the core and half mass radii, searching down to a luminosity of 1.3 x 1031 ergs s-1 in the 0.5-5 keV range. Most sources have bolometric X-ray luminosities between…
Discovery of a helium-core white dwarf progenitor
Heber, U.; Napiwotzki, R.; Lisker, T. +1 more
We discovered that HD 188112, a bright (V = \magpt{10}{2}), nearby (80 pc) B-type star, is a unique subluminous B (sdB) star. SdB stars are usually identified with models of core helium burning Extreme Horizontal-Branch (EHB) stars of half a solar mass. A spectral analysis of the hydrogen and helium lines resulted in T_eff = 21 500 +/- 500 K, log …
Near-IR echelle spectroscopy of Class I protostars: Mapping Forbidden Emission-Line (FEL) regions in [FeII]
Ray, T. P.; Chrysostomou, A.; Davis, C. J. +1 more
Near-IR echelle spectra in [FeII] 1.644 mu m emission trace Forbidden Emission Line (FEL) regions towards seven Class I HH energy sources (SVS 13, B5-IRS1, IRAS 04239+2436, L1551-IRS5, HH 34-IRS, HH 72-IRS and HH 379-IRS) and three classical T Tauri stars (AS 353A, DG Tau and RW Aur). The parameters of these FEL regions are compared to the charact…
ISOGAL: A deep survey of the obscured inner Milky Way with ISO at 7 mu m and 15 mu m and with DENIS in the near-infrared
Genzel, R.; Price, S. D.; Alard, C. +51 more
The ISOGAL project is an infrared survey of specific regions sampling the Galactic Plane selected to provide information on Galactic structure, stellar populations, stellar mass-loss and the recent star formation history of the inner disk and Bulge of the Galaxy. ISOGAL combines 7 and 15 µm ISOCAM observations -- with a resolution of 6 arcse…
Simultaneous multi-wavelength observations of GRS 1915+105
Goldoni, P.; Chaty, S.; Rodriguez, J. +11 more
We present the result of multi-wavelength observations of the microquasar GRS 1915+105 in a plateau state with a luminosity of ~ 7.5*E38 erg s-1 ( ~ 40% L_Edd), conducted simultaneously with the INTEGRAL and RXTE satellites, the ESO/NTT, the Ryle Telescope, the NRAO VLA and VLBA, in 2003 April 2-3. For the first time were obs…
A Keplerian disk around the Herbig Ae star HD 34282
Kahane, C.; Dutrey, A.; Piétu, V.
We report new millimeter observations of the circumstellar material surrounding the Herbig Ae A0.5 star HD 34282 performed with the IRAM array in CO ~ and in continuum at 1.3 mm. These observations have revealed the existence of a large Keplerian disk around the star. We have analysed simultaneously the line and continuum emissions to derive the p…
INTEGRAL/SPI ground calibration
Knödlseder, J.; von Kienlin, A.; Bouchet, L. +30 more
Three calibration campaigns of the spectrometer SPI have been performed before launch in order to determine the instrument characteristics, such as the effective detection area, the spectral resolution and the angular resolution. Absolute determination of the effective area has been obtained from simulations and measurements. At 1 MeV, the effecti…