A large fraction of all stars, after experiencing heavy winds at the end of the Asymptotic Giant Branch (AGB) phase, leave behind a core that is below the Chandrasekhar mass limit. This core eventually photoionizes the stellar ejecta giving birth to a planetary nebula (PN). PN and AGB stars are therefore the remnants of stars that through their

We report on our recent 3D numerical models of the launching of hot, high-speed jets in a coronal hole following the emergence of magnetized plasma from the solar interior. As part of the same research, we have also analyzed Hinode (EIS and XRT) and Soho-MDI observational data of an actual process of flux emergence followed by jet launching in a

The ultraluminous X-ray source (ULX) Holmberg II X-1 has been observed over four months in 2009/2010 by the Swift observatory. The source luminosity varied by a factor of up to 14, reaching a maximum 0.3-10 keV luminosity of ~3.0 × 1040 erg s-1. The spectral properties do not vary much over these four months, with only a slight monotonic increase

On Nov 19, 2001, The Chandra X-ray Observatory surveyed M31 with 5 overlapping very short (1ks) HRC exposures and a single short (5ks) ACIS-S exposure. Preliminary analysis allows us to report the following concerning possible X-ray transients within M31. A new source CXOU J004428.4+415628 (RA=00:44:28.4, DEC=+41:56:28.1, J2000), near the NE spiral

We combine bright XMM-Newton data with the Chandra Deep Field South observations to explore the behavior of the intrinsic AGN absorption, as a function of redshift and luminosity. Our sample consists of 359 sources selected in the hard 2-8 keV band, spanning the flux range 6 × 10-16-3 × 10-13 erg~cm-2~s-1 with a high rate of spectroscopic or

This paper presents the results of a detailed X-ray spectral analysis of a sample of 123 X-ray sources detected with XMM-Newton in the Lockman Hole field. This is the deepest observation carried out with XMM-Newton with more that 600 ks of good EPIC-pn data. We have spectra with good signal to noise (>500 source counts) for all objects down to 0.2