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Supersoft X-Ray Sources in M31. I. A Chandra Survey and an Extension to Quasi-soft Sources
Barmby, P.; Greiner, J.; Murray, S. S. +9 more
We report on very soft X-ray sources (VSSs) in M31. In a survey that was most sensitive to soft sources in four 8'×8' regions covered by Chandra's ACIS-S S3 CCD, we find 33 VSSs that appear to belong to M31. Fifteen VSSs have spectral characteristics mirroring the supersoft X-ray sources studied in the Magellanic Clouds and M…
A joint mid-infrared spectroscopic and X-ray imaging investigation of LINER galaxies
Dudik, R. P.; Satyapal, S.; Sambruna, R. M.
We present a comprehensive comparative high resolution mid-IR spectroscopic and X-ray imaging investigation of LINERs using archival observations from the ISO-SWS and the Chandra Advanced CCD Imaging Spectrometer. Although the sample is heterogenous and incomplete, this is the first comprehensive study of the mid-infrared fine structure line emiss…
Interpretation of Cluster data on chorus emissions using the backward wave oscillator model
Trakhtengerts, V. Y.; Demekhov, A. G.; Titova, E. E. +4 more
The measurements of chorus emissions by four closely separated Cluster spacecraft provide important information concerning the chorus generation mechanism. They confirm such properties of the wave source as their strong localization near the equatorial cross section of a magnetic flux tube, an almost parallel average wave-vector direction with res…
Magnetic Fields in the Solar Convection Zone
Fan, Yuhong
Recent studies of the dynamic evolution of magnetic flux tubes in the solar convection zone are reviewed with focus on emerging flux tubes responsible for the formation of solar active regions. The current prevailing picture is that active regions on the solar surface originate from strong toroidal magnetic fields generated by the solar dynamo mec…
A phase-dependent absorption line in the spectrum of the X-ray pulsar RX J0720.4-3125
Haberl, F.; Burwitz, V.; Trümper, J. +1 more
The XMM-Newton spectra of the isolated neutron star
Determination of magnetic helicity content of solar active regions from SOHO/MDI magnetograms
Moon, Yong-Jae; Chae, Jongchul; Park, Young-Deuk
Chae (2001) first proposed a method of self-consistently determining the rate of change of magnetic helicity using a time series of longitudinal magnetograms only, such as taken by SOHO/MDI. Assuming that magnetic fields in the photosphere are predominantly vertical, he determined the horizontal component of velocity by tracking the displacements …
Nonlinear guiding center theory of perpendicular diffusion: General properties and comparison with observation
Qin, Gang; Matthaeus, W. H.; Shalchi, Andreas +1 more
A nonlinear guiding center (NLGC) theory for diffusion of charged particles perpendicular to the mean magnetic field was recently proposed. Here, we draw attention to a number of attractive features of this theory: (1) The theory provides a natural mechanism to connect the perpendicular mean free path with the parallel mean free path. In fact, the…
Nitrogen and Oxygen Abundance Variations in the Outer Ejecta of η Carinae: Evidence for Recent Chemical Enrichment
Smith, Nathan; Morse, Jon A.
We present optical spectra of the ionized ``outer ejecta'' of η Car that reveal differences in chemical composition at various positions. In particular, young condensations just outside the dusty Homunculus nebula show strong nitrogen lines and little or no oxygen, but farther away, nitrogen lines weaken and oxygen lines become stronger. The obser…
The metal content of the bulge globular cluster NGC 6528
Minniti, D.; Pasquini, L.; Zoccali, M. +7 more
High resolution spectra of five stars in the bulge globular cluster NGC 6528 were obtained at the 8m VLT UT2-Kueyen telescope with the UVES spectrograph. Out of the five stars, two of them showed evidence of binarity. The target stars belong to the horizontal and red giant branch stages, at 4000 < Tefflt; 4800 K. Multiband V, I, J, H…
Cassini UVIS observations of the Io plasma torus. II. Radial variations
Steffl, Andrew J.; Stewart, A. Ian F.; Bagenal, Fran
On January 14, 2001, shortly after the Cassini spacecraft's closest approach to Jupiter, the Ultraviolet Imaging Spectrometer (UVIS) made a radial scan through the midnight sector of Io plasma torus. The Io torus has not been previously observed at this local time. The UVIS data consist of 2-D spectrally dispersed images of the Io plasma torus in …