Search Publications
Polar, Cluster and SuperDARN evidence for high-latitude merging during southward IMF: temporal/spatial evolution
Wild, J. A.; Lester, M.; Dunlop, M. +5 more
Magnetic merging on the dayside magnetopause often occurs at high latitudes. Polar measured fluxes of accelerated ions and wave Poynting vectors while skimming the subsolar magnetopause. The measurements indicate that their source was located to the north of the spacecraft, well removed from expected component merging sites. This represents the fi…
Emission-Line Galaxies in the Space Telescope Imaging Spectrograph Parallel Survey. I. Observations and Data Analysis
Gardner, Jonathan P.; Teplitz, Harry I.; Rhodes, Jason +5 more
In the first 3 years of operation the Space Telescope Imaging Spectrograph (STIS) obtained slitless spectra of ~2500 fields in parallel to prime Hubble Space Telescope (HST) observations as part of the STIS parallel survey (SPS). The archive contains ~300 fields at high Galactic latitude (b>30deg) with spectroscopic exposure times gr…
Propagation velocities of gas rings in collisional ring galaxies
Bizyaev, D.; Vorobyov, E. I.
The propagation velocity of the first gas ring in collisional ring galaxies, i.e. the velocity at which the maximum in the radial gas density profile propagates radially in the galactic disk, is usually inferred from the radial expansion velocity of gas in the first ring. Our numerical hydrodynamics modeling of ring galaxy formation however shows …
pnCCDs on XMM-Newton—42 months in orbit
Haberl, Frank; Freyberg, Michael; Dennerl, Konrad +11 more
XMM-Newton—a cornerstone mission of the European Space Agency's Horizon 2000 programme—was launched on December 10, 1999 into orbit. Since March 2000 more than 2000 scientific observations were made. An example will be shown. The X-ray pnCCD camera on EPIC is operating since then without severe problems. We will report about the system performance…
An analysis of the emission line spectra of AG Pegasi between phases 7.34 and 9.44
Contini, Marcella
The UV and optical spectra from the HST Faint Object Spectrograph and from the Fast Spectrograph for the Tillinghast Telescope (FAST) spectrograph at the Whipple Observatory reported by Kenyon, Proga & Keyes at different phases are analysed, leading to new results about the configuration of AG Pegasi. The FAST spectra contain both Hα and Hβ li…
870 Micron Observations of Nearby 3CRR Radio Galaxies
Quillen, A. C.; Yukita, Mihoko; Almog, Jessica
We present submillimeter continuum observations at 870 µm of the cores of low-redshift 3CRR radio galaxies, observed at the Heinrich Hertz Submillimeter Telescope. The cores are nearly flat-spectrum between the radio and submillimeter, which implies that the submillimeter continuum is likely to be synchrotron emission and not thermal emissio…
Improved Hipparcos Parallaxes of Coma Berenices and NGC 6231
Makarov, Valeri V.
A method to reprocess the Hipparcos Intermediate Astrometry Data that reduces the propagation of the along-scan spacecraft attitude errors was developed and successfully used to obtain a more consistent parallax of the Pleiades (Makarov, published in 2002). The same technique is used now to correct the Hipparcos parallaxes of the Coma Berenices an…
Detection of type 2 quasars in the radio galaxies B3 0731+438 and 3C 257
O'Brien, P. T.; Reeves, J. N.; Ward, M. J. +3 more
We present XMM-Newton observations and spectral fitting of two high-redshift, [OIII]-luminous, narrow-line radio galaxies, B3 0731+438 and 3C 257. Their X-ray continua are well fitted by a partial covering model with intrinsically unabsorbed and absorbed power-law components. The spectral models indicate that both objects harbour highly obscured n…
Line shape diagnostics of Galactic 26Al
Hartmann, D. H.; Diehl, R.; Kretschmer, K.
The shape of the gamma-ray line from radioactive 26Al, at 1808.7 keV energy in the frame of the decaying isotope, is determined by its kinematics when it decays, typically 106 y after its ejection into the interstellar medium from its nucleosynthesis source. Three measurements of the line width exist: HEAO-C's 1982 value of (…
Lens or Binary? Chandra Observations of the Wide-Separation Broad Absorption Line Quasar Pair UM 425
Green, Paul J.; Aldcroft, Thomas L.
We have obtained a 110 ks Chandra ACIS-S exposure of UM 425, a pair of QSOs at z=1.47 separated by 6.5", which show remarkably similar emission and broad absorption line (BAL) profiles in the optical/UV. Our 5000 count X-ray spectrum of UM 425A (the brighter component) is well fitted with a power law (photon spectral index Γ=2.0) partially covered…