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Heavy Element Abundances in Late-B and Early-A Stars. I. Co-Added IUE Spectra of HgMn Stars
Leckrone, D. S.; Wahlgren, G. M.; Adelman, S. J. +2 more
Very heavy elements (Pt, Au, Hg, Tl, and Bi) are found to be enhanced in the atmospheres of the chemically peculiar stars of the upper main sequence by up to a million times the solar system levels. Such enhancements are believed to result from atmospheric dynamics (i.e., diffusion) rather than scenarios that dredge up nuclear-processed material t…
XMM-Newton Study of A3562 and Its Immediate Shapley Environs
Finoguenov, A.; Kaastra, J. S.; de Plaa, J. +2 more
Using a mosaic of six XMM-Newton observations, we study the hydrodynamic state of A3562, a cluster in the center of the Shapley supercluster. The X-ray image reveals a sharp surface brightness gradient within the core of A3562, a 200 kpc ridge extending to the southwest. A nearby group, SC 1329-313, imaged within this program also exhibits a tail …
Molecular and dust features of 29 SiC carbon AGB stars
He, Jinhua; Yang, Xiaohong; Chen, Peisheng
We have reduced and analyzed the Infrared Space Observatory (ISO) Short-Wavelength Spectrometer (SWS) spectra of 29 infrared carbon stars with a silicon carbide feature at 11.30 µm, 17 of which have not been previously published. Absorption or emission features of C2, HCN, C2H2, C3 and silicon carb…
XMM-Newton observations of three high-redshift radio galaxies
Lawrence, C. R.; Hardcastle, M. J.; Birkinshaw, M. +2 more
We present the results of XMM-Newton observations of three powerful high-redshift radio galaxies 3C184, 3C292 and 3C322. Although none of the sources lies in as rich an X-ray-emitting environment as is seen for some powerful radio galaxies at low redshift, the environments provide sufficient pressure to confine the radio lobes. The weak gas emissi…
Ni Abundance in the Core of the Perseus Cluster: An Answer to the Significance of Resonant Scattering
Gastaldello, Fabio; Molendi, Silvano
Using an XMM-Newton observation of the Perseus cluster we show that the excess in the flux of the 7-8 keV line complex previously detected by ASCA and BeppoSAX is due to an overabundance of nickel rather than to an anomalously high Fe Heβ/Fe Heα ratio. This observational fact leads to the main result that resonant scattering, which was assumed to …
On the Hipparcos parallaxes of O stars
Kaper, L.; Schröder, S. E.; Brown, A. G. A. +1 more
We compare the absolute visual magnitude of the majority of bright O stars in the sky as predicted from their spectral type with the absolute magnitude calculated from their apparent magnitude and the Hipparcos parallax. We find that many stars appear to be much fainter than expected, up to five magnitudes. We find no evidence for a correlation be…
Timing analysis of the isolated neutron star RX J0720.4-3125 revisited
Cropper, Mark; Zavlin, Vyacheslav E.; Haberl, Frank +1 more
We present a reanalysis of the X-ray data for RX J0720.4-3125 presented in our previous paper, Zane et al., using more data recently available from XMM-Newton and Chandra. This analysis also corrects the ROSAT data used in that paper to the barycentric dynamical time (TDB) system, incorporates the revised XMM-Newton barycentric correction availabl…
XMM-Newton Observations of an Intermediate X-Ray Object in NGC 2276
Mushotzky, Richard F.; Davis, David S.
We present the results from a ~53 ks XMM-Newton observation of NGC 2276. This galaxy has an unusual optical morphology with the disk of this spiral appearing to be truncated along the western edge. This XMM-Newton observation shows that the X-ray source at the western edge is a bright intermediate X-ray object (IXO). Its spectrum is well fitted by…
Resolving the Stellar Population of the Standard Elliptical Galaxy NGC 3379
Ferguson, Henry C.; Gregg, Michael D.; Minniti, Dante +2 more
Using the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on board the Hubble Space Telescope, we have obtained F110W (~J) and F160W (~H) images of three fields in NGC 3379, a nearby normal giant elliptical galaxy. These images resolve individual red giant stars, yielding the first accurate color-magnitude diagrams for a normal luminou…
Relationship between solar wind low-energy energetic ion enhancements and large geomagnetic storms
Smith, Z.; Murtagh, W.; Smithtro, C.
It is well established that energetic ion enhancements (an energetic ion enhancement will hereafter be referred to as an EIE) are partly due to acceleration by interplanetary shocks as the shocks propagate towards Earth and that arrivals of these shocks at Earth are well associated with geomagnetic storms. The observation of EIEs at satellites loc…