Search Publications
Spectral properties of nonthermal X-ray emission from the shell-type SNR RX J1713.7 3946 as revealed by XMM-Newton
Hiraga, J. S.; Takahashi, T.; Uchiyama, Y. +1 more
We present the results of our morphological and spectral study of the properties of the supernova remnant RX J1713.7-3946 based on data obtained with XMM-Newton. Highly inhomogeneous structures, such as the bright spots, filaments, and dark voids noted by Uchiyama et al. ([CITE]), appear in the entire bright western portion of the shell. In additi…
Characteristics of the near-tail dawn magnetopause and boundary layer
Klecker, B.; Vaivads, A.; Hasegawa, H. +6 more
The paper discusses properties of the near-tail dawnside and boundary layer, as obtained from Cluster plasma and magnetic field measurements during a single skimming orbit on 4 and 5 July 2001 that included 24 well-defined crossings by all four spacecraft. As a result of variations of the interplanetary magnetic field, the magnetic shear across th…
The pulsed X-ray light curves of the isolated neutron star RBS1223
Haberl, F.; Motch, C.; Schwope, A. D. +1 more
We present a multi-epoch spectral and timing analysis of the isolated neutron star RBS1223. New XMM-Newton data obtained in January 2004 confirm the spin period to be twice as long as previously thought, P_spin = 10.31 s. The combined ROSAT, Chandra, and XMM-Newton data (6 epochs) give, contrary to earlier findings, no clear indication of a spin e…
Spatially Resolved Spectroscopy and Coronagraphic Imaging of the TW Hydrae Circumstellar Disk
Weinberger, Alycia J.; Roberge, Aki; Malumuth, Eliot M.
We present the first spatially resolved spectrum of scattered light from the TW Hydrae protoplanetary disk. This nearly face-on disk is optically thick, surrounding a classical T Tauri star in the nearby 10 Myr old TW Hya association. The spectrum was taken with the Hubble Space Telescope (HST) STIS CCD, providing resolution R~360 over the wavelen…
A Far-Ultraviolet Spectroscopic Survey of Luminous Cool Stars
Young, P. R.; Linsky, J. L.; Lobel, A. +3 more
The Far Ultraviolet Spectroscopic Explorer (FUSE) ultraviolet spectra of eight giant and supergiant stars reveal that high-temperature (3×105 K) atmospheres are common in luminous cool stars and extend across the color-magnitude diagram from α Car (F0 II) to the cool giant α Tau (K5 III). Emission present in these spectra includes chrom…
Elemental Abundances in Two High Column Density Damped Lyα Systems at z < 1.5
Rao, Sandhya M.; Howk, J. Christopher; Wolfe, Arthur M. +1 more
We present Keck HIRES abundance measurements and metal-line kinematic profiles of the damped Lyα systems (DLAs) toward the quasars Q0933+733 (zabs=1.479) and Q0948+433 (zabs=1.233). These two DLAs have among the five highest H I column densities at any redshift: N(HI)=4.2×1021 cm-2. The metal-line data, …
AWM 4 - an isothermal cluster observed with XMM-Newton
O'Sullivan, E.; Vrtilek, J. M.; David, L. P. +2 more
We present an analysis of an XMM-Newton observation of the poor cluster AWM 4. The cluster is relaxed and its X-ray halo is regular with no apparent substructure. Azimuthally averaged radial spectral profiles suggest that the cluster is isothermal to a radius of at least 160 kpc, with no evidence of a central cooling region. Spectral mapping shows…
XMM-Newton detection of hot gas in the Eskimo Nebula: Shocked stellar wind or collimated outflows?
Gruendl, R. A.; Chu, Y. -H.; Guerrero, M. A. +1 more
The Eskimo Nebula (NGC 2392) is a double-shell planetary nebula (PN) known for the exceptionally large expansion velocity of its inner shell, ∼90 km s-1, and the existence of a fast bipolar outflow with a line-of-sight expansion velocity approaching 200 km s-1. We have obtained XMM-Newton observations of the Eskimo and detect…
Time-Distance Helioseismology: Inversion of Noisy Correlated Data
Kosovichev, A. G.; Birch, A. C.; Gizon, L. +2 more
In time-distance helioseismology most inversion procedures ignore the correlations in the data errors. Here we simulate the travel-time perturbations of wavepackets that result from known distributions of sound speed inhomogeneities. The forward and inverse problems are carried out using recently developed Born approximation sensitivity kernels. A…
Dispersion analysis of low-frequency waves through the terrestrial bow shock
Glassmeier, K. -H.; Narita, Y.
We present dispersion relations of low-frequency waves observed upstream and downstream of the Earth's bow shock analyzing Cluster magnetometer measurements along an outbound orbit covering four regions: the foreshock, the outer, the middle, and the inner magnetosheath. The aim of our study is to better understand wave transmission, mode conversio…