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The INTEGRAL spectrometer SPI: performance of point-source data analysis
Knödlseder, J.; von Kienlin, A.; Bouchet, L. +9 more
The performance of the SPI point-source data analysis system is assessed using a combination of simulations and of observations gathered during the first year of INTEGRAL operations. External error estimates are derived by comparing source positions and fluxes obtained from independent analyses. When the source detection significance provided by t…
Pulsation of the K 2.5 giant star GSC 09137-03505?
Zwintz, K.; Guenther, D. B.; Weiss, W. W. +2 more
In July, 1999, the Hubble Space Telescope (HST) pointed for more than 8 days continuously at the globular cluster 47 Tucanae. Two guide stars were used during this campaign by the Fine Guidance Sensors (FGS). Using more than 19 million photometric FGS data for the guide star GSC 09137-03505 we found brightness variability corresponding to three ap…
Star cluster detection with WFC/ACS in M 33. 33 new clusters and 51 candidates
Anderson, J.; Baume, G.; Momany, Y. +5 more
In this work we present the detection of 33 star clusters and 51 candidates in one field of the near by galaxy M 33. This study is based on WFC/ACS images available from the HST archive. Thanks to the high resolving power, we were able to confirm that two candidates previously indicated by Christian & Schommer (1982, ApJS, 49, 405) are indeed …
Discovery of an X-Ray Nova in M31
Williams, Benjamin F.; Kong, Albert K. H.; Murray, Stephen S. +2 more
We have obtained snapshot images of an X-ray nova in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys. The Chandra position of the X-ray nova was R.A.=00h44m06.68s 68+/-1.74s, decl.=+41deg12'20.0"+/-2.31" (J2000.0). A follow-up HST observation 24 days later reveale…
Identification of the Source Region of a ``Halo'' Coronal Mass Ejection Using Meter-Wavelength Radio Data
Ramesh, R.; Kathiravan, C.
We present meter-wavelength observations of the solar corona close to the onset of the ``halo'' coronal mass ejection (CME) of 1998 January 21 and estimate the change in electron density with time through a reproduction of the observed two-dimensional radio brightness distribution using a ray-tracing technique. Our calculations show that the avera…
The Planets and Titan Observed by ISO
Bézard, Bruno; Fouchet, Thierry; Encrenaz, Therese
Infrared spectroscopic observations of planets and Saturn's satellite Titan with the Infrared Space Observatory led to many significant discoveries that improved our understanding on the formation, physics and chemistry of these objects. The prime results achieved by ISO are: (1) a new and consistent determination of the D/H ratios on the giant pl…
Evidence for explosive event activity originating in the chromosphere
Doyle, J. G.; Bryans, P.; Summers, H. P. +2 more
We report on a joint SUMER, CDS, TRACE study, concentrating on a region which shows prolonged EUV explosive event (EE) activity in the transition region line N v 1238 Å, yet little evidence of such activity in another transition region line O v 629 Å (formed at a similar temperature) which was observed simultaneously. A possible explanation for th…
The field Am and ρ Puppis-like stars: Lithium and heavier elements
Gerbaldi, M.; Burkhart, C.; Coupry, M. F. +1 more
With observations at the Canada-France-Hawaii telescope, photospheric abundances of two evolved field Am stars,
The XMM-Newton spectrum of the high-z optically-obscured QSO RX J1343.4+0001: a classic radio quiet QSO
Cappi, M.; Guainazzi, M.; Schartel, N. +2 more
We present a 30 ks XMM-Newton observation of the z = 2.35 type II radio quiet quasar RX J1343.4+0001. These data provide the first good quality X-ray spectrum for this object. We measured a continuum slope Γ = 1.85±0.10 with only an upper limit on the column density of the absorbing material of NHz ⪉ 1022 cm-2…
Re-determination of Phoebe's orbit
Qiao, R. C.; Shen, K. X.; Dourneau, G. +2 more
In order to improve the orbit of Phoebe, the ninth satellite of the Saturnian system, 101 new observations were made by our research team in 2003, using a CCD detector of large size (2048×2048 pixels) mounted on the 1.56 m astrometric reflector at the Sheshan Station of Shanghai Astronomical Observatory. We fitted a numerical integration of its or…