Search Publications
Line formation regions of the UV spectrum of C I Cygni
Friedjung, M.; Mikołajewska, J.; Quiroga, C.
Aims.They are the interpretation of the emission line formation regions in
Methods: .They involve the examination of radial velocities and fluxes of ultraviolet emission lines at different epochs, deduced from archival IUE and GRHS/HST spectra.
Results: .The line fluxes give electron densities and were in additi…
Shock excitation of the knots of Hen 3-1475
Binette, L.; Raga, A. C.; Riera, A.
We present new optical STIS HST spectroscopic observations of the jets of the proto-planetary nebula Hen3-1475. The excitation conditions of the knots of Hen3-1475
are derived from the observed optical spectra, confirming that the knots are shock excited. The shocked spectra are qualitatively reproduced by simple "3/2"Dbow shock models. …The extragalactic Cepheid bias: a new test using the period-luminosity-color relation
Paturel, G.; Teerikorpi, P.
We use the Period-Luminosity-Color relation (PLC) for Cepheids to test for the existence of a bias in extragalactic distances derived from the classical Period-Luminosity (PL) relation. We calculate the parameters of the PLC using several galaxies observed with the Hubble Space Telescope and show that this calculation must be conducted with a PLC …
High resolution optical spectroscopy of IRAS 09425-6040 (=GLMP 260)
García-Lario, P.; García-Hernández, D. A.; Abia, C. +1 more
We present high resolution optical spectroscopic observations of IRAS 09425-6040, a peculiar, extremely red, C-rich AGB star showing prominent O-rich dust features in its ISO infrared spectrum attributed to crystalline silicates. Our analysis shows that IRAS 09425-6040 is indeed a C-rich star slightly enriched in lithium ({log (Li/H) + 12} ∼ 0.7) …
A new luminous supersoft X-ray source in NGC 300
Schirmer, M.; Wilms, J.; Kendziorra, E. +1 more
Context: .We report the discovery of a new luminous supersoft source,
Identification of the broad solar emission features near 117 nm
Kurucz, R. L.; Avrett, E. H.; Loeser, R.
Wilhelm et al. have recently called attention to the unidentified broad emission features near 117 nm in the solar spectrum. They discuss the observed properties of these features in detail but do not identify the source of this emission. We show that the broad autoionizing transitions of neutral sulfur are responsible for these emission features.…
Matched filters for source detection in the Poissonian noise regime
Stewart, I. M.
A procedure is described for estimating an optimum kernel for the detection by convolution of signals among Poissonian noise. The technique is applied to the detection of X-ray point sources in XMM-Newton data, and is shown to yield an improvement in detection sensitivity of up to 60% over the sliding-box method used in the creation of the 1XMM ca…
GMRT observations of the field of INTEGRAL X-ray sources. II
Durouchoux, P.; Ishwara-Chandra, C. H.; Manchanda, R. +2 more
We conducted low-frequency radio observations with the Giant Metrewave Radio Telescope (GMRT) of the 40 new hard X-ray sources discovered by the INTEGRAL satellite. This survey was conducted in order to study radio emissions from these sources, to provide precise position, and to identify new microquasar candidates. Our observations show that 24 o…
A compact flare eclipsed in the corona of SV Camelopardalis
Sanz-Forcada, J.; Micela, G.; Favata, F.
The eclipsing active binary SV Cam (G0V/K6V, Porb=0.593071 d) was observed with XMM-Newton during two campaigns in 2001 and 2003. No eclipses in the quiescent emission are clearly identified, but a flare was eclipsed during the 2001 campaign, allowing us to strongly constrain, from purely geometrical considerations, the position and siz…
Transition region counterpart of a moving magnetic feature
Doyle, J. G.; Banerjee, D.; O'Shea, E. +1 more
Context: .While moving magnetic features have been studied extensively at the photospheric level, the effect they have on the upper atmosphere remains largely unknown, and it is this which we seek to address in this work.
Aims: .In this work we aim to investigate the chromospheric and transition-region dynamics associated with a moving magneti…