Search Publications
Elemental abundances in the intracluster medium as observed with XMM-Newton
Kaastra, J. S.; Tamura, T.; Bleeker, J. A. M. +2 more
XMM-Newton observations of 19 galaxy clusters are used to measure the elemental abundances and their spatial distributions in the intracluster medium. The sample mainly consists of X-ray bright and relaxed clusters with a cD galaxy. Along with detailed Si, S and Fe radial abundance distributions within 300-700 kpc in radius, the O abundances are a…
Flares from small to large: X-ray spectroscopy of Proxima Centauri with XMM-Newton
Audard, M.; Güdel, M.; Linsky, J. L. +2 more
We report results from a comprehensive study of the nearby M dwarf Proxima Centauri with the XMM-Newton satellite, using simultaneously its X-ray detectors and the Optical Monitor with its U band filter. We find strongly variable coronal X-ray emission, with flares ranging over a factor of 100 in peak flux. The low-level emission is found to be co…
Study of the properties and spectral energy distributions of the Herbig AeBe stars HD 34282 and HD 141569
Rauer, H.; Schneider, J.; Eiroa, C. +21 more
We present a study of the stellar parameters, distances and spectral energy distributions (SEDs) of
Tentative identification of urea and formamide in ISO-SWS infrared spectra of interstellar ices
Duvernay, F.; Chiavassa, T.; Dartois, E. +4 more
Laboratory experiments involving vacuum ultraviolet (VUV) irradiation of solid isocyanic acid (HNCO) at 10 K, followed by infrared spectroscopy (FTIR), are used to interpret the complex spectra associated with Interstellar Medium (ISM) dust grains, particularly the spectra associated with the icy phase observed toward dense molecular clouds. The c…
2-10 keV luminosity of high-mass binaries as a gauge of ongoing star-formation rate
Cappi, M.; Franceschini, A.; Braito, V. +4 more
Based on recent work on spectral decomposition of the emission of star-forming galaxies, we assess whether the integrated 2-10 keV emission from high-mass X-ray binaries (HMXBs), L2-10HMXB, can be used as a reliable estimator of ongoing star formation rate (SFR). Using a sample of 46 local (z ⪉ 0.1) star-forming galaxies, and…
Photometric redshifts with the Multilayer Perceptron Neural Network: Application to the HDF-S and SDSS
Popesso, P.; Fontana, A.; Vanzella, E. +8 more
We present a technique for the estimation of photometric redshifts based on feed-forward neural networks. The Multilayer Perceptron (MLP) Artificial Neural Network is used to predict photometric redshifts in the HDF-S from an ultra deep-multicolor catalog. Various possible approaches for the training of the neural network are explored, including t…
The XMM-Newton and BeppoSAX view of the Ultra Luminous Infrared Galaxy MKN 231
Cappi, M.; Franceschini, A.; Piconcelli, E. +11 more
We discuss XMM-Newton and BeppoSAX observations of MKN 231, the lowest-redshift Broad Absorption Line (BAL) QSO known so far and one of the best-studied Ultra Luminous Infrared Galaxies. By combining the XMM-Newton spectral resolution and the high-energy bandpass of BeppoSAX we have been able to study in more detail than previously possible its 0.…
The SUMER spectral atlas of solar coronal features
Curdt, W.; Landi, E.; Feldman, U.
We present a spectral atlas of the solar corona in the far-ultraviolet (FUV) and extreme ultraviolet (EUV) wavelength range. The atlas is based on observations obtained between 670 Å and 1609 Å in first order of diffraction and between 465 and 670 Å in second order with the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph o…
The HELLAS2XMM survey. VI. X-ray absorption in the 1df AGN sample through a spectral analysis
Maiolino, R.; Perola, G. C.; Fiore, F. +13 more
The spectroscopic analysis of 117 serendipitous sources in the HELLAS2XMM 1df (1 degree field) survey is described. Of these, 106 sources, of which 86% have a spectroscopic redshift, are used to evaluate the fraction of X-ray absorbed (log NH>22) Active Galactic Nuclei (AGN) in the 2-10 keV flux range 0.8-20×10-14 erg cm
The initial helium abundance of the Galactic globular cluster system
Salaris, M.; Riello, M.; Piotto, G. +1 more
In this paper we estimate the initial He content in about 30% of the Galactic globular clusters (GGCs) from new star counts we have performed on the recently published HST snapshot database of Colour Magnitude Diagrams (Piotto et al. \cite{Piotto02}). More specifically, we use the so-called R-parameter and estimate the He content from a theoretica…