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Register a new userXMM-Newton First Observation in the Pleiades
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We present the first results from a 40 ks Guaranteed Time XMM-Newton pointing in the Pleiades. We detect almost all early-mid dM members in the field and several very low mass (VLM) stars - including the brown dwarf (BD) candidate Roque 9 - and investigate the variation of X-ray activity levels, hardness ratios and flare frequency with spectral type down to the BD regime.
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We present the first X-ray observation of Jupiter by XMM-Newton. Images taken with the EPIC cameras show prominent emission, essentially all confined to the 0.2-2.0 keV band, from the planets auroral spots; their spectra can be modelled with a combination of unresolved emission lines of highly ionised oxygen (OVII and OVIII), and a pseudo-continuum which may also be due to the superposition of many weak lines. A 2.8 sigma enhancement in the RGS spectrum at 21-22 A (~0.57 keV) is consistent with an OVII identification. Our spectral analysis supports the hypothesis that Jupiters auroral emissions originate from the capture and acceleration of solar wind ions in the planets magnetosphere, followed by X-ray production by charge exchange. The X-ray flux of the North spot is modulated at Jupiters rotation period. We do not detect evidence for the ~45 min X-ray oscillations observed by Chandra more than two years earlier. Emission from the equatorial regions of the planets disk is also observed. Its spectrum is consistent with that of scattered solar X-rays.
We report on the first XMM-Newton observation of the bright Narrow-Line Seyfert 1 galaxy Mrk 110. We find a narrow Fe K fluorescent line, a broad component FWHM ~ 16500 km/s of the OVII triplet, either due to infall motions or gravitational redshift effects in the vicinity of the central black hole, a Comptonized accretion disc layer, and a strong starburst component. If the broad redshifted soft X-ray components are due to gravitational redshift effects, the distance of the line emitting regions ranges between about 0.2 and 1 light day with respect to the central black hole.
We present the observation of the Tycho supernova remnant obtained with the EPIC and RGS instruments onboard the XMM-Newton satellite. We compare images and azimuthally averaged radial profiles in emission lines from different elements (silicon and iron) and different transition lines of iron (Fe L and Fe K). While the Fe XVII L line and Si XIII K line images are globally spatially coincident, the Fe K emission clearly peaks at a smaller radius, indicating a higher temperature toward the reverse shock. This is qualitatively the profile expected when the reverse shock, after travelling through the outer power-law density profile, has entered the central plateau of the ejecta. The high energy continuum map has an overall smooth distribution, with a similar extent to the radio emission. Its radial profile peaks further out than the lines emission. Brighter and harder continuum regions are observed with a rough bipolar symmetry in the eastern and western edges. The spectral analysis of the southeastern knots supports spatial variations of the relative abundance of silicon and iron, which implies an incomplete mixing of the silicon and iron layers.
We present an {sl XMM-Newton} observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary. The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star. The EPIC and RGS spectra of Algol in its quiescent state are described by a two-temperature plasma model. The cool component has a temperature around 6.4$times 10^{6}$ K while that of the hot component ranges from 2 to 4.0$times 10^{7}$ K. Coronal abundances of C, N, O, Ne, Mg, Si and Fe were obtained for each component for both the quiescent and the flare phases, with generally upper limits for S and Ar, and C, N, and O for the hot component. F-tests show that the abundances need not to be different between the cool and the hot component and between the quiescent and the flare phase with the exception of Fe. Whereas the Fe abundance of the cool component remains constant at $sim$0.14, the hot component shows an Fe abundance of $sim$0.28, which increases to $sim$0.44 during the flare. This increase is expected from the chromospheric evaporation model. The absorbing column density $N_H$ of the quiescent emission is 2.5$times10^{20}$ cm$^{-2}$, while that of the flare-only emission is significantly lower and consistent with the column density of the interstellar medium. This observation substantiates earlier suggestions of the presence of X-ray absorbing material in the Algol system.
We present the first optical validation of an X-ray Line-Emitting Object (XLEO) discovered in the XMM-Newton observation of the Chandra Deep Field South. The object is an AGN at z_x ~ 0.66. An optical spectrum of the source indeed confirms and refines (z_o = 0.665) the redshift obtained from the X-ray line. The X-ray and optical properties of the source are presented and discussed.
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