Search Publications
Constraints on the star formation history of the Large Magellanic Cloud
Santiago, B. X.; Kerber, L. O.; Javiel, S. C.
We present the analysis of deep colour-magnitude diagrams (CMDs) of 6 stellar fields in the LMC. The data were obtained using HST/WFPC2 in the F814W (∼I) and F555W (∼V) filters, reaching V555 ∼ 26.5. We discuss and apply a method of correcting CMDs for photometric incompleteness. A method to generate artificial CMDs based on a model sta…
XMM-Newton spectroscopy of the metal depleted T Tauri star TWA 5
Neuhäuser, R.; Peres, G.; Stelzer, B. +2 more
We present results of X-ray spectroscopy for
The 90-110 µm dust feature in low to intermediate mass protostars: Calcite?
Maret, S.; Ceccarelli, C.; Chiavassa, A. +2 more
We present ISO spectra between 60 and 180 µm of 32 protostars of low to intermediate mass. About half of the spectra present a dust feature between ~90 and ~110 µm. We describe the observational characteristics of this feature, which seems to be due to one single carrier. In Class 0 sources the feature peaks around 100 µm, while …
The XMM-Newton Ω project
Bernard, J. -P.; Nichol, R. C.; Romer, A. K. +10 more
We study the gas mass fraction behavior in distant galaxy clusters observed within the XMM-Newton Ω project. The typical gas mass fraction fgas shape of high redshift galaxy clusters follows the global shape inferred at low redshift quite well, once scaled appropriately: the gas mass fraction increases with radius and flattens outward. …
Decay properties of the X-ray afterglows of gamma-ray bursts
Gendre, B.; Boër, M.
We present a set of seventeen Gamma-Ray Bursts (GRBs) with known redshifts and X-ray afterglow emission. We apply cosmological corrections in order to compare their fluxes normalized at a redshift of 1. Two classes of GRB can be defined using their X-ray afterglow light curves. We show that the brightest afterglows seem to decay faster than the di…
The correlation between coronal Doppler shifts and the supergranular network
Peter, H.; Lemaire, P.; Aiouaz, T.
We examine properties of line profiles as found with large raster scans of the solar corona acquired by the UV spectrometer SUMER on board SOHO. The observed regions include an equatorial coronal hole, a polar coronal hole, as well as surrounding quiet Sun areas. In order to reveal the network and remove strong local brightenings, a filter is appl…
Further evidence for the presence of a neutron star in 4U 2206+54 . INTEGRAL and VLA observations
Mirabel, I. F.; Reig, P.; Torrejón, J. M. +5 more
The majority of High Mass X-ray Binaries (HMXBs) behave like X-ray pulsars, revealing that they contain a magnetised neutron star. Among the four HMXBs showing neither pulsations nor the characteristics of accreting black holes, there is the unusual HMXB
On the 3-dimensional structure of the streamer belt of the solar corona
Llebaria, A.; Zhukov, A. N.; Lamy, P. +1 more
We investigate the three-dimensional structure of the streamer belt of the solar corona using a model that allows us to simulate its quasi-stationary configuration. Starting from the National Solar Observatory photospheric magnetograms, the position of the neutral line at the source surface (2.5 ~R_⊙) is determined using the potential field source…
Enhanced X-ray variability from V1647 Ori, the young star in outburst illuminating McNeil's Nebula
Hamaguchi, K.; Grosso, N.; Kastner, J. H. +5 more
We report a 38 ks X-ray observation of McNeil's Nebula obtained with XMM-Newton on 2004 April 4. V1647 Ori, the young star in outburst illuminating McNeil's Nebula, is detected with XMM-Newton and appears variable in X-rays. We investigate the hardness ratio variability and time variations of the event energy distribution with quantile analysis, a…
On the formation of the He I 10 830 Å line in a flaring atmosphere
Ding, M. D.; Li, H.; Fang, C.
We explore the formation of the He i 10 830 Å line in a flaring atmosphere, with special attention to the nonthermal effects of an electron beam. Using non-LTE calculations we obtain the line profiles from different model atmospheres. Without the nonthermal effects, the line changes from weak absorption in a cool atmosphere to emission in a hot an…