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Abundances and Physical Conditions in the Interstellar Gas toward HD 185418
York, Donald G.; Welty, Daniel E.; Snow, Theodore P. +2 more
We present a study of the abundances and physical conditions in the interstellar gas toward the moderately reddened B0.5 V star HD 185418. This star is located at (l,b)=(53deg,-2.2d) and has an estimated distance of 790 pc and a reddening E(B-V)=0.50. This work is based on the analysis of Far Ultraviolet Spectroscopic Explore…
Chandra Observations of Low-Mass X-Ray Binaries and Diffuse Gas in the Early-Type Galaxies NGC 4365 and NGC 4382 (M85)
Sarazin, Craig L.; Sivakoff, Gregory R.; Irwin, Jimmy A.
We used the Chandra X-Ray Observatory ACIS-S3 to image the X-ray-faint elliptical galaxy NGC 4365 and lenticular galaxy NGC 4382. The observations resolve much of the X-ray emission into 99 and 58 sources, respectively, most of which are low-mass X-ray binaries (LMXBs) associated with each of the galaxies. Within one effective radius of NGC 4365, …
Signature of an Avalanche in Solar Flares as Measured by Photospheric Magnetic Fields
Wang, H.; Goode, P. R.; Abramenko, V. I. +2 more
We analyzed time variations of turbulent parameters of the photospheric magnetic field of four active regions obtained during the course of major solar flares using longitudinal magnetograms from the Big Bear Solar Observatory and from SOHO/MDI full-disk measurements. Analysis of the data indicated that, before each flare, the degree of intermitte…
Evolution of Conjugate Footpoints inside Flare Ribbons during a Great Two-Ribbon Flare on 2001 April 10
Shimojo, Masumi; Yokoyama, Takaaki; Kurokawa, Hiroki +2 more
We report a detailed examination of the fine structure inside flare ribbons and the temporal evolution of such structure during an X2.3 solar flare, which occurred on 2001 April 10. We examined fine structures, such as systems of conjugate footpoints, inside flare ribbons by using the Hα images obtained with the Sartorius telescope at Kwasan Obser…
An XMM-Newton and Chandra Investigation of the Nuclear Accretion in the Sombrero Galaxy (NGC 4594)
Pellegrini, S.; Baldi, A.; Fabbiano, G. +1 more
We present an analysis of the XMM-Newton and Chandra ACIS-S observations of the LINER nucleus of the Sombrero galaxy, and we discuss possible explanations for its very sub-Eddington luminosity by complementing the X-ray results with high angular resolution observations in other bands. The X-ray investigation shows a hard (Γ=1.89) and moderately ab…
A Multiwavelength Study of the High-Field Magnetic White Dwarf EUVE J0317-85.5 (=RE J0317-853)
Vennes, Stéphane; Christian, D. J.; Wickramasinghe, D. T. +3 more
We present optical and ultraviolet photometry and spectroscopy and optical circular spectropolarimetry of the ultramassive, rapidly rotating, high-field magnetic white dwarf EUVE J0317-85.5. From the combined data sets, we establish an ephemeris for the photometric, spectroscopic, and polarimetric variations with a spin period of 725.7277 s, the f…
New Light on the Stellar Populations in I Zw 18: Deep Near-Infrared Imaging
Hunt, Leslie K.; Thuan, Trinh X.; Izotov, Yuri I.
We present deep JHK images of I Zw 18, the most metal deficient blue compact dwarf galaxy known, and analyze them in conjunction with archival Hubble Space Telescope/Wide Field Planetary Camera 2 optical images. To investigate the stellar populations, we have divided the main body of I Zw 18 into eight regions and fitted the optical, near-infrared…
Molecular Outflows in the Young Open Cluster IC 348
Stanke, Thomas; Eislöffel, Jochen; McCaughrean, Mark J. +1 more
We present a wide-field survey of the young open cluster IC 348 for molecular H2 outflows. Outflow activity is only found at its southwestern limit, where a new subcluster of embedded sources is in an early phase of its formation. If the IC 348 cluster had been built up by such subclusters forming at different times, this could explain …
Sympathetic Coronal Mass Ejections
Moon, Y. -J.; Wang, Haimin; Choe, G. S. +1 more
We address the question whether there exist sympathetic coronal mass ejections (CMEs), which take place almost simultaneously in different locations with a certain physical connection. For this study, the following three investigations are performed. First, we have examined the waiting-time distribution of the CMEs that were observed by the SOHO L…
X-Ray Observations of the Compact Central Object in Supernova Remnant G347.3-0.5
Gaensler, B. M.; Hughes, J. P.; Galloway, D. K. +4 more
We present Chandra, XMM-Newton, and Rossi X-Ray Timing Explorer observations of 1WGA J1713.4-3949, a compact source at the center of the Galactic supernova remnant (SNR) G347.3-0.5. The X-ray spectrum of the source is well fitted by the sum of a blackbody component with a temperature of ~0.4 keV plus a power-law component with a photon index of ~4…