Search Publications
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 …
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…
Mg II chromospheric radiative loss rates in cool active and quiet stars
Cardini, D.
The Mg II k emission line is a good indicator of the level of chromospheric activity in late-type stars. We investigate the dependence of this activity indicator on fundamental stellar parameters. To this purpose we use IUE observations of the Mg II k line in 225 late-type stars of luminosity classes I-V, with different levels of chromospheric act…
Signs of warm-hot intergalactic medium in the soft X-ray background
Sołtan, A. M.; Freyberg, M. J.; Hasinger, G.
Small angular scale structure of the soft X-ray background correlated with the galaxy distribution is investigated. An extensive data sample from the ROSAT and XMM-Newton archives are used. Excess emission below 1 keV extending up to at least several hundred kpc around galaxies is detected. The relative amplitude of the excess emission in the 0.3-…
Sub-arcsecond imaging of the radio continuum and neutral hydrogen in the Medusa merger
Aalto, S.; Beswick, R. J.; Hüttemeister, S. +1 more
We present sub-arcsecond, Multi-Element Radio Linked Interferometer (MERLIN) observations of the decimetre radio continuum structure and neutral hydrogen (Hi) absorption from the nuclear region of the starburst galaxy NGC 4194 (the Medusa Merger). The continuum structure of the central kiloparsec of the Medusa has been imaged, revealing a pair of …
The recurrent ultra-luminous X-ray transient NGC 253 ULX1
Pietsch, W.; Bauer, M.
We present the results of ROSAT and XMM-Newton observations of the recurrent ultraluminous X-ray source (ULX)