Search Publications
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…
Massive Elliptical Galaxies at High Redshift: NICMOS Imaging of z~1 Radio Galaxies
Dickinson, Mark; Dey, Arjun; Zirm, Andrew W.
We present deep, ~1.6 µm, continuum images of 11 high-redshift (0.811<z<1.875) 3CR radio galaxies observed with NICMOS on board the Hubble Space Telescope. Our NICMOS images probe the rest-frame optical light where stars are expected to dominate the galaxy luminosity. The rest-frame ultraviolet light of eight of these galaxies demonstr…
Temporal Variation of Angular Momentum in the Solar Convection Zone
Howe, R.; Komm, R.; Hill, F. +1 more
We derive the angular momentum as a function of radius and time with the help of the rotation rates resulting from inversions of helioseismic data obtained from the Global Oscillation Network Group (GONG) and the Michelson Doppler Imager (MDI) and the density distribution from a model of the Sun. The base of the convection zone can be identified a…
Chandra Observations of Expanding Shells in the Dwarf Starburst Galaxy NGC 3077
Martin, Crystal L.; Ott, Jürgen; Walter, Fabian
Deep Chandra observations (53 ks, ACIS-S3) of NGC 3077, a starburst dwarf galaxy in the M81 triplet, resolve the X-ray emission from several supershells. The emission is brightest in the cavities defined by expanding shells detected previously in Hα emission. Thermal emission models fitted to the data imply temperatures ranging from ~1.3 to 4.9×10…