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Coronal Loops Heated by Magnetohydrodynamic Turbulence. I. A Model of Isobaric Quiet-Sun Loops with Constant Cross Sections
Chae, Jongchul; Aschwanden, Markus J.; Poland, Arthur I.
Several recent papers have presented new observational results indicating that many coronal loops in active regions are nearly isothermal. It is expected that quiet-Sun loops may have similar thermal structures, since quiet-Sun differential emission measures look similar to those in active regions. In the quiet Sun, it is well known from observati…
The Interpretation of the Emission Spectra of the Seyfert 2 Galaxy NGC 7130: Determination of the Active Galactic Nucleus and Starburst Contributions
Rafanelli, P.; Radovich, M.; Contini, M. +1 more
Detailed modeling of the different regions of NGC 7130 is presented, accounting for its composite nature of an active galactic nucleus (AGN) and a starburst galaxy. Shock waves, created by stellar winds from hot massive stars and by supernova ejecta, are evident in the continuum and line spectra emitted from the clouds. Therefore, the SUMA code, w…
Hubble Space Telescope Spectroscopy of the Dwarf Nova RX Andromedae during Outburst Rise and Decline
Szkody, Paula; Sion, Edward M.; Gänsicke, Boris T. +1 more
We obtained Hubble Space Telescope far-ultraviolet spectra of the Z Cam-type dwarf nova RX And during the early rise to outburst and the decline from the same outburst. The spectral wavelength range covered was 1149-1435 Å. The rise spectrum is dominated by strong, very broad absorption lines, while the decline spectrum has strong, narrower absorp…
A Hyper Extremely Red Object in the Field near 53W002
Tanaka, Ichi; Im, Myungshin; Yamada, Toru +1 more
Hyper extremely red objects (HEROs) are objects that are very red in near-IR colors (J-K>~3). They are speculated to be intrinsically red galaxies at z>~2 or Lyman break galaxies at z>10. We report the discovery of a HERO in the field that includes a known radio galaxy, 53W002, and a possible cluster of galaxies both at z=2.39. The HERO, …
Far-Ultraviolet Observations of Comet 2P/Encke at Perihelion
Raymond, J. C.; Wu, R.; Gardner, L. +6 more
Comet 2P/Encke was observed with UVCS/SOHO near perihelion (2000 September 9 and 11) in the Lyman lines of hydrogen. We present a Lyα image reconstructed from a series of long-slit spectra, along with the intensity ratios of Lyα, Lyβ, and Lyγ. The narrow Lyα profile indicates that the observed photons are scattered from hydrogen atoms produced by …
Kinematics of OB Stars
Branham, Richard L., Jr.
The kinematics of 1817 stars of class O-B5 are examined. The 1655 stars with distances up to 1 kpc are taken from the Hipparcos catalog and 162 stars with distances greater than 1 kpc from Westlin's study of OB stars. The Ogorodnikov-Milne model of Galactic kinematics, with Edmondson's second-order terms included, is used for the equations of cond…
Complete Models of Axisymmetric Sunspots: Magnetoconvection with Coronal Heating
Alexander, David; Hurlburt, Neal E.; Rucklidge, Alastair M.
We present detailed results of numerical experiments into the nature of complete sunspots. The models remain highly idealized but include fully nonlinear compressible magnetoconvection in an axisymmetric layer that drives energy into an overlying, low-β plasma. We survey a range of parameters in which the resulting magnetoconvection displays the f…
INTEGRAL Field Spectroscopy of IRAS 15206+3342: Gas Inflows and Starbursts in an Advanced Merger
Arribas, Santiago; Colina, Luis
Integral field optical spectroscopy using the INTEGRAL system (complemented with Hubble Space Telescope WFPC2 imaging) is used to characterize the kinematic and ionization properties of the warm ionized gas in the ultraluminous infrared galaxy IRAS 15206+3342. These data present kinematic and morphological evidence for a tidal tail connecting the …
An Upper Limit to the Mass of the Radial Velocity Companion to ρ1 Cancri
Han, Inwoo; Gatewood, George; Black, David C. +7 more
Doppler spectroscopy of ρ1 Cnc has detected evidence of a companion with an orbital period of 14.65 days and a minimum mass of 0.88 Jupiter masses. Astrometric observations performed with the Hubble Space Telescope Fine Guidance Sensor 1r using a novel observing technique have placed an upper limit on the astrometric reflex motion of ρ<…
Radio Galaxies at z = 1.1 to 3.8: Adaptive Optics Imaging and Archival Hubble Space Telescope Data
Hutchings, J. B.; Crampton, D.; Steinbring, E.
We have undertaken a program of high-resolution imaging of high-redshift radio galaxies (HzRGs), using adaptive optics on the Canada-France-Hawaii Telescope. We report on deep imaging in J, H, and K bands of six HzRGs in the redshift range 1.1 to 3.8. At these redshifts, near-infrared bandpasses sample the rest-frame visible galactic light. The ra…