Search Publications
XMM-Newton spectroscopy of high-redshift quasars
Córdova, F. A.; Mason, K. O.; Puchnarewicz, E. M. +2 more
We present XMM-Newton X-ray spectra and optical photometry of four high-redshift (z= 2.96-3.77) quasars, [HB89] 0438-436, [HB89] 2000-330, [SP89] 1107+487 and RX J122135.6+280613 of these four objects, the first two are radio-loud and the last two are radio-quiet. Model fits require only a power law with Galactic absorption in each case; additiona…
Cluster observations of quasi-periodic impulsive signatures in the dayside northern lobe: High-latitude flux transfer events?
Balogh, A.; Khurana, K. K.; Fazakerley, A. N. +4 more
We report on a series of quasi-periodic reversals in GSM BZ observed by the four Cluster spacecraft in the northern dayside lobe poleward of the cusp on 23 February 2001. During an interval of about 35 min, multiple reversals (negative to positive) in BZ of approximately 1-min duration with an approximate 8-min recurrence tim…
Latitudinal transport effects on the modulation of a few-MeV cosmic ray electrons from solar minimum to solar maximum
Fichtner, H.; Wibberenz, G.; Ferreira, S. E. S. +2 more
A three-dimensional, steady state, numerical model was used to model the propagation of 7 MeV jovian and galactic electrons in the heliosphere. The computations are compared with 3-10 MeV Ulysses/KET electron observations which are still not well explained after ∼1998. To explain these observations, coinciding with solar maximum conditions, it is …
A New Unidentified Far-Infrared Band in NGC 7027
Cernicharo, José; Goicoechea, Javier R.; Masso, Helena +1 more
We report on the detection of a molecular band centered at ~98 µm (~102 cm-1), observed with the Infrared Space Observatory in the young planetary nebula NGC 7027. The band structure and intensity cannot be reproduced by atomic fine-structure lines, recombination lines, or the rotational emission of abundant molecules. We discuss …
The Magnetostatic Cleanliness Program for the Cassini Spacecraft
Narvaez, P.
The Cassini spacecraft, launched in October 1997 and expected to reach Saturn in 2004, carries two magnetometer experiments on a 10-m boom, one at the mid-section of the boom and the other situated at the end of the boom. In order to gather valid scientific magnetic field data and avoid electromagnetic interference, the spacecraft had to comply wi…
A Mid-Infrared Survey of L1641N with ISOCAM
Noriega-Crespo, Alberto; Ali, Babar
We present the results from our analysis of the Infrared Space Observatory (ISO) data on the L1641N outflow region located in the Orion A molecular cloud. The data were obtained with the array camera (ISOCAM) using two broadband filters, LW2 (6.7 µm) and LW3 (14 µm), and the narrowband circular variable filter (CVF), which provides low…
A Far-Ultraviolet Spectroscopic Analysis of the Central Star of the Planetary Nebula Longmore 1
Bianchi, L.; Herald, J. E.
We have performed a non-LTE spectroscopic analysis using far-UV and UV data of the central star of the planetary nebula K1-26 (Longmore 1) and found Teff=120+/-10 kK, logg=6.7+0.3-0.7 cm s-2, and Y~=0.10. The temperature is significantly hotter than previous results based on optical line analyses, highli…
Simulating Titan’s tropospheric circulation with the Portable University Model of the Atmosphere
Keller, H. U.; Grieger, B.; Rodin, A. V. +4 more
The Portable University Model of the Atmosphere (PUMA) is a general circulation model of intermediate complexity. In the model setup used herein, the dynamics is driven by restoration to a prescribed temperature field. Given an observed three-dimensional field of restoration temperatures, the feedback of aerosol distribution to the radiation schem…
The Ultraviolet Spectrum of the High-Field Magnetic Cataclysmic Variable AR Ursae Majoris
Gänsicke, B. T.; Szkody, Paula; Hoard, D. W. +4 more
We have obtained an ultraviolet spectrum covering the range 917-1182 Å of the high-field magnetic cataclysmic variable AR Ursae Majoris when the binary was in its typical low-accretion state. The data reveal an array of deep Zeeman absorption features due to hydrogen Lyα-Lyγ, including several transitions that are normally forbidden but become ena…
Chandra observations of SNR 1987A
McCray, R.; Hasinger, G.; Garmire, G. P. +4 more
We report on the results of our monitoring program of the X-ray remnant of supernova 1987A with the Chandra X-ray Observatory. We have performed two new observations during the Chandra Cycle 3 period, bringing the total to six monitoring observations over the past three years. These six observations provide a detailed time history of the birth of …