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Spatial and temporal variations in interstellar absorption towards HD 72127AB
Welty, Daniel E.; Hobbs, L. M.; Simon, Thuso
New optical spectra of CaII and NaI towards HD 72127AB provide additional evidence for both spatial and temporal variations in the complex interstellar absorption along the two sightlines; archival ultraviolet spectra yield information on the abundances, depletions and physical conditions in the gas towards HD 72127A. Similarities in the strengths…
Ultraviolet Observations of the X-Ray Photoionized Wind of Cygnus X-1 during X-Ray Soft/High State
Bolton, C. T.; Vrtilek, S. D.; Gies, D. +2 more
High-resolution ultraviolet observations of Cygnus X-1 were obtained at two epochs roughly 1 year apart using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. Orbital phase ranges around phiorb = 0 and 0.5 were covered at each epoch, and the spectra show P Cygni line features from high (N V, C IV, Si IV) and absor…
Abundance Inhomogeneity in the Northeastern Rim of the Cygnus Loop Revealed by the Suzaku Observatory
Miller, Eric D.; Katsuda, Satoru; Uchida, Hiroyuki +5 more
We present the results of a spatially resolved spectral analysis from four Suzaku observations covering the northeastern rim of the Cygnus Loop. A two-kTe non-ionization equilibrium (NEI) model fairly well represents our data, which confirms the NEI condition of the plasma there. The metal abundances are depleted relative to the solar v…
The Chandra ACIS Survey of M33 (ChASeM33): Investigating the Hot Ionized Medium in NGC 604
Blair, William P.; Hughes, John P.; Ghavamian, Parviz +7 more
NGC 604 is the largest H II region in M33, second only within the Local Group to 30 Dor, and is important as a laboratory for understanding how massive young stellar clusters interact with the surrounding interstellar medium. Here we present deep (300 ks) X-ray imagery of NGC 604 obtained as part of the Chandra ACIS Survey of M33 (ChASeM33), which…
Comparison of Heliospheric In Situ Data with the Quasi-steady Solar Wind Models
Riley, P.; Lepri, S. T.; Antiochos, S. K. +2 more
The standard theory for the solar-heliospheric magnetic field is the so-called quasi-steady model in which the field is determined by the observed magnetic flux at the photosphere and the balance between magnetic and plasma forces in the corona. In this model, the solar magnetic flux that opens to the heliosphere can increase or decrease as the ph…
Helium Line Formation and Abundance during a C-Class Flare
Andretta, Vincenzo; Teriaca, Luca; Mauas, Pablo J. D. +1 more
During a coordinated campaign that took place in 2001 May, a C-class flare was observed both with SOHO instruments and with the Dunn Solar Telescope of the National Solar Observatory at Sacramento Peak. In two previous papers we described the observations and discussed some dynamical aspects of the earlier phases of the flare, as well as the heliu…
Ultra-Compact Dwarf Candidates Near the Lensing Galaxy in Abell S0740
Blakeslee, John P.; Barber DeGraaff, Regina
We analyze three-band imaging data of the giant elliptical galaxy ESO 325-G004 from the Hubble Space Telescope Advanced Camera for Surveys (ACS). This is the nearest known strongly lensing galaxy, and it resides in the center of the poor cluster Abell S0740 at redshift z = 0.034. Based on magnitude, color, and size selection criteria, we identify …
Proper Frame Determination and Walen Test
Sonnerup, Bengt U. O.; Paschmann, Gotz
To study structures, such as current sheets, flux ropes, or fully three-dimensional configurations, it is desirable to examine them in their proper (co-moving) frame, in which they appear as time stationary as the data permit. And it is important to establish the frame velocity so that their physical dimensions can be determined. In the present ch…
Coronal loop slow mode oscillations driven by the kink instability
Verwichte, E.; Haynes, M.; Arber, T. D.
Aims:To establish the dominant wave modes generated by an internal, m=1 kink instability in a short coronal flux tube.
Methods: The 3D MHD numerical simulations are performed using Lare3d to model the kink instability and the subsequent wave generation. The initial conditions are a straight, zero net current flux tube containing a twist higher…
Track analysis of energetic neutral atom blobs at Saturn
Krimigis, S. M.; Mitchell, D. G.; Roelof, E. C. +2 more
A statistical analysis of observations of the Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft at Saturn reveals the morphology and dynamics of energetic neutral atoms (ENA). The ENA (20-50 keV hydrogens) images are smoothed and projected onto Saturn's equatorial plane, and the intensities are slant-corrected using a thin-disk ap…