Search Publications
The eclipsing millisecond pulsar PSR J1740-5340 and its red straggler companion
van Kerkwijk, M. H.; Orosz, J. A.
We present a high-resolution echelle spectrum taken with the Very Large Telescope and analyse archival Hubble Space Telescope photometry of the recently identified companion of the eclipsing millisecond radio pulsar
Discovery of narrow X-ray absorption features from the low-mass X-ray binary X 1254-690 with XMM-Newton
Parmar, A. N.; Boirin, L.
We report on two XMM-Newton observations of the low-mass X-ray binary X 1254-690. During an XMM-Newton observation of the low-mass X-ray binary in 2001 January a deep X-ray dip was seen while in a second observation one year later no dips were evident. The 0.5-10 keV EPIC spectra from both non-dipping intervals are very similar being modeled by a …
Are stellar coronae optically thin in X-rays?. A systematic investigation of opacity effects
Schmitt, J. H. M. M.; Mewe, R.; Audard, M. +2 more
The relevance of resonant scattering in the solar corona has always been discussed controversially. Ratios of emission lines from identical ions but different oscillator strengths have been used in order to estimate damping of resonance lines due to possible resonant scattering, i.e., absorption by photo-excitation and re-emission out of the line …
New results on GP Com
Marsh, T. R.; Steeghs, D.; Morales-Rueda, L. +3 more
We present high resolution optical and UV spectra of the 46 min orbital period, helium binary, GP Com. Our data contains simultaneous photometric correction which confirms the flaring behaviour observed in previous optical and UV data. In this system all lines show a triple peaked structure where the outer two peaks are associated with the accreti…
More nitrogen rich B-type stars in the SMC cluster, NGC 330
Dufton, P. L.; Lennon, D. J.; Crowley, C.
High resolution spectra of seven early B-type giant/supergiant stars in the SMC cluster NGC 330 are analysed to obtain their chemical compositions relative to SMC field and Galactic B-type stars. It is found that all seven stars are nitrogen rich with an abundance approximately 1.3 dex higher than an SMC main-sequence field B-type star, AV304. The…
The origin of the iron lines in NGC 7213
Perola, G. C.; Bianchi, S.; Balestra, I. +1 more
The analysis of a simultaneous XMM-Newton/BeppoSAX plus three previous BeppoSAX observations revealed that NGC 7213 is a rather peculiar Seyfert 1. No significant Compton reflection component was observed, while an iron line complex, best explained in terms of three narrow lines, is clearly apparent in the data. Due to the absence of the reflectio…
Coronal Mass Ejection (CME)-induced shock formation, propagation and some temporally and spatially developing shock parameters relevant to particle energization
Wu, S. T.; Tsurutani, B.; Dryer, M. +1 more
Interplanetary shocks accelerate solar energetic particles (SEPs) from the point of shock formation in the lower corona, and continuously as the shock propagates outward to 1 AU and beyond. In this study, the formation properties of a CME-induced shock and propagation characteristics are studied from the inner corona to 1 AU. We use a 2D, three-co…
Latitudinal structure and north-south asymmetry of the solar wind from Lyman-alpha remote sensing by SWAN
Bzowski, M.; Quémerais, E.; Summanen, T. +2 more
Based on SWAN/SOHO observations carried out during 1996-2002, we analyze latitudinal profiles of the heliospheric backscatter Lyman-alpha radiation. We use these results to investigate the ionization field of neutral hydrogen in the inner heliosphere and the latitudinal distribution of the solar wind mass flux. The the depth and latitudinal range …
X-ray rotational modulation of a supersaturated star in IC 2391
Micela, G.; Peres, G.; Sciortino, S. +1 more
We present evidence of X-ray rotational modulation on VXR45, a young fast rotator star, member of IC 2391. It is a dG9 spectral type star whose rotational period and X-ray luminosity make it a supersaturated star. Our X-ray observation, made with EPIC/PN on XMM-Newton, covers about two photometric rotational periods. The detection of X-ray rotatio…
Molecular gas in the central regions of the latest-type spiral galaxies
Schinnerer, E.; Böker, T.; Lisenfeld, U.
Using the IRAM 30 >m telescope, we have surveyed an unbiased sample of 47 nearby spiral galaxies of very late (Scd-Sm) Hubble-type for emission in the 12CO(1-0) and (2-1) lines. The sensitivity of our data (a few mK) allows detection of about 60% of our sample in at least one of the CO lines. The median detected H2 mass is…